Hello, <!—-><!—->
I’ve posted this question on Woodcentral and am cross-posting here in hopes of generating more ideas.<!—->
I’m looking for a fix for poor surface quality on my Powermatic model 15 planer. <!—->
The photo below shows the problem on the planed surface. The bruises or dents are hemicylindrical in shape. Scooped out, in other words. The dents are .004″ to .006″ deep, measured with a dial indicator. <!—->
It’s not tearout; the dents can be steamed out. Also it is not caused by chips sticking to the outfeed rollers. That sometimes happens; the resulting indent has a different shape. <!—->
Cherry and maple samples show similar denting. Mahogany shows much less denting. <!—->
A 1/32″ depth of cut greatly reduces denting, but doesn’t eliminate it. Photos below show dents at 1/16″ and 1/32″. This is on the same cherry board using both faces. <!—->
I purchased the planer new in June 2004. At the time it was hooked up to a 1 hp dust collector. I attributed the bruising to inadequate dust collection. However when I upgraded the dust collection to a 2 h.p. cyclone the problem persisted. Powermatic sent me a new set of knives and gibs which had no effect on the problem. As they’ve ignored my last two emails I presume they’re out of ideas. <!—->
I’ve tried several other things to correct the problem. I set the chip breaker and outfeed roller to specification. I tried moistening the wood surface. No effect. I tried different planer speeds, 16 and 20 fpm. No effect. There’s a red plastic guard next to the cutterhead. I varied the distance from the guard to the cutter head with no effect on surface bruising. <!—->
Has anyone seen a similar condition on planed stock, or have suggestions for a fix? <!—->
Ed<!—->
Replies
Ed,
That sure looks to me like the chips aren't being evacuated from the planer. Maybe you need a bigger port/duct/hose? I'm not familiar with powermatic #15, how big is the exit port from the hood? I've got an old Parks 12" machine with a 6" duct going to the collector, sometimes it still gets clogged with shavings.
Regards,
Ray
Hi Ray -
Thanks for the quick response. The planer has a 4" dust port. I may have to bump that up.
Ed
Ed -- I have the same planer and on occasion have the same problem. In spite of your initial thought about the chips on the outfeed roller not being the problem, I believe that is causing the dimples. I just finished planing about 100 BF of cypress from 8/4 to 5/4 and had the problem whenever the dust collector got full (or blocked) or when the chip shroud got clogged up. Cleaning the shroud eliminated the problem every time. Same thing when I've planed cherry or walnut. In your case it might be the chip breaker clearance being too open or just not enough vacuum to keep the ships moving out. My suggestion is to assume the dimples are being caused by chips being embossed into the planed surface and look for the cause before looking for a more exotic reason. If you have the owner's manual for the machine, or can talk with the company tech support, see what the spec is for the chip breaker. Incidentally, the 15-inch Powermatic is the exact same machine (except for switch and cosmetics) as the Jet and a bunch of others, so any one of the brands could supply you with the roller/chip breaker specs. If all else fails, remove the shroud and use the planer open -- without the shroud -- to see what happens. (You'll need to do this out in the open, naturally, because you'll create a snowstorm of wood chips!) Good luck.
I agree with the earlier post. the chips are getting pulled back around and getting between the blade and the smashed into the surface which was just planed.
If you don't enlarge the duct work, make sure that all other gates are closed, and that the filters are clean. You may even need a bigger blower.
Ed,
I agree with Jim, remove the shroud and see if this changes the results. I routinely roll my planer outside and run without the shroud when planing wide stock I have a 5" line to the planer's 4" port and it is really inadequate but I haven't't got around to building a new shroud with a 5" port, which, in my opinion, is what it requires.
Doug
I'll add my two bit pea brain observations to the queue....
that indentation at the 3.5" mark is definititely a chip impression.
and I ain't not expert by any stretch of the imagination, but some of the other indentations look like burnishing caused be debris caught between the rollers and the table.
Now while some folks might say "the dust collector ain't workin good enuf". I'd suggest that maybe it's workin too well, ie not allowing the bigger pieces to fall away, but rather sucking them back up into the spaces between the bottom rollers and the bed. The rollers roll em up into that gap, a jam-fit , and hold em there, yer wood gets forced over them by the upper feed rollers. .
I dunno, just some wild conjecture on my part, I have seen bits of knots caught up in my rollers do almost exactly the same thing. But then again, I normally don't use dust collection on the planer.
Maybe my observations don't help you a bit, but could be easily tested by turning off the dust collector...
Eric in Calgary
Ed,
Absolutely definitely those marks result from chips going where they are not required, and then sticking to the out feed roller and or the bed rollers and the out table possibly.
I am not familiar with your machine but there normally is a chip deflector/hood which directs the direction of the chip "spray"- is this in the correct position?.
The machines of yore,that were not used in conjunction with chip collectors, only suffered your problem when the beds, bed rollers and feed rollers became contaminated with stuff like resin which is sticky, or the operator was chewing huge cuts at max feed speeds.
Have you made sure that all is clean and not sticky?
I have a vintage British machine which has no provision for chip collection- I only get that problem if the bed rollers and particularly the outfeed roller are no longer clean-soft and resinous woods are the cause , so regular cleaning is in order.Your machine should still give a reasonable finish without the use of a chip collector.
Good luck.
Edited 5/6/2005 4:44 am ET by mookaroid
So, come on , what have you done? I am willing to bet that the problem goes if you do not use the dust collector, give all rollers a good cleaning using emery tape or similar take an average cut and make sure that that red plastic 'guard" is not doing the wrong thing. You got some suggestions so let us know what happens.
The danged thing is not supposed to damage your work so the cause must be found and eliminated!
Thanks for the nudge, and sorry for the delay. I’ve been spraying finish the past few days and had to defer testing until yesterday. I didn’t want to comment on anyone’s suggestions until I had a chance to test them. I tried several suggestions for eliminating the surface problems. In brief, nothing worked. The long version follows. <!----><!---->
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Several folks thought the marks were caused by chips getting under the outfeed roller and getting their shape embossed in the stock surface. There is one instance of this visible in the surface.jpg image above the 3.25” mark on the ruler. The other marks appear quite different; edges are feathered out. If anyone is still unconvinced, I’ll take a closeup of an embossed dent.<!---->
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Another suggestion was to clean all the planer internal workings. The planer exhibited this strange denting phenomenon right out of the box. At present the machine is clean, rollers clean, and bed waxed. <!---->
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Some suggested trying a cut without the dust shrouds in place. Others thought the chip deflector should be (a.) removed or (b.) adjusted snug to the cutting circle. For those unfamiliar with the chip deflector, see attachment for an image of the chip deflector in position (with two bolts removed). It’s the light orange object toward the back of the image.<!---->
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Depth of cut for all tests was 1/16”. I set the feed rate for 16 fpm, i.e. the slower speed. I used properly jointed cherry, maple and quartersawn oak stock for test pieces. Roller heights and chip breaker height are set properly. Blades are new and sharp. This is the third set of blades on this machine with no effect on results.<!---->
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I removed the dust shrouds. With the shrouds off (and obviously the dust collection inoperative) I tested with (a.) the chip deflector removed and (b.) with the chip deflector installed and adjusted to 1/64” above the blades. No improvement noted in either case. Also, in either case, no embossing of chips under the outfeed roller was observed. Previously I’ve tested with the chip deflector in less extreme positions, with no effect on surface quality noted.<!---->
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With the dusts shrouds re-attached and the dust collector operating I tested with the chip deflector (a.) removed and (b.) installed and tight to the blade. No improvement noted in either case and again no problems with chips under the outfeed rollers. When the chip deflector is close to the blades, air flow over the deflector makes a very loud howling noise. <!---->
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With dust shrouds in place, dust collector on, and chip deflector removed I sent a few wide boards through the planer. I noticed less but still unacceptable denting where the annual rings are roughly parallel to the planed surface, and more where the rings are perpendicular to the planed surface, i.e. quartersawn. I didn’t see any other pattern to the dents. Feeding two boards side-by-side, each 7” wide caused no clogging. No chips escape from either the infeed or outfeed openings. I think the dust collection is more than adequate for the job.<!---->
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Conclusions: Since the chip deflector has no observed effect on surface quality, I’m going to leave it off. The machine is much quieter without it. For now I’ll make final passes at 1/32” as that does create fewer dents. And, I’ll look into a larger 5” or 6” dust port but don’t expect it will help.<!---->
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My thanks to all who took the time to read and respond to my question. I’ve cross-posted this note on Woodcentral.<!---->
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Ed <!---->
Nice shot of your new planer. I see it has the newer dust shroud that's angled to the side like the Jet. Your detailed description of the problem and your attempts to diagnosis it leave me scratching my head. Tell me this -- do you see any chips on the surface of the planed boards as they exit the machine? On my Powermatic, the only time I see chips on the boards coming out of the machine is also when there are embossed marks. Could it be that not all of the chips are getting thrown out or sucked out as they are supposed to, but that some are staying in the chamber and falling down on the boards as they go under the final roller? Have you tried blowing out any chips left from earlier passes that might be left inside? That's the only thing I can think of. Does the machine do a decent job of planing otherwise?I've found that embossing occurs more often when I'm taking bigger bites, but I see that you've already tried changing that variable. Even when I'm reducing rough lumber down to finish size I don't turn the elevation crank more than one turn which, on my machine, is a bit less than 1/16. Also, sometimes chips will collect in corners or other places inside and work their way out a little at a time -- which is why I asked if you've tried to blow out any chips that may not have come out normally.My son, who is a finish carpenter, has one of these machines also and so far both of our experiences match. Makes me wonder if there might be a problem specific to yours (?).
Do you see any chips on the surface of the planed boards as they exit the machine?
No.
Does the machine do a decent job of planing otherwise?
Yes, the surface is excellent except for the dings. No scallops, no tearout if grain direction is considered, negligible snipe.<!----><!---->
I've found that embossing occurs more often when I'm taking bigger bites, but I see that you've already tried changing that variable. Even when I'm reducing rough lumber down to finish size I don't turn the elevation crank more than one turn which, on my machine, is a bit less than 1/16.
Yes, that’s my typical procedure as well.
Also, sometimes chips will collect in corners or other places inside and work their way out a little at a time -- which is why I asked if you've tried to blow out any chips that may not have come out normally.
The dust collector works very well. There are no chips inside the machine. Ever.
My son, who is a finish carpenter, has one of these machines also and so far both of our experiences match. Makes me wonder if there might be a problem specific to yours (?).
Aha. Two machines that work well. Yes, that seems to indicate the problem is specific to my machine. Thanks for the additional thoughts. I really appreciate your feedback.
Ed
Well, I'd sure like to know what the h... is causing your dings...
Ed,
Sory for not throwing my 2-bits in, but I'm new to this site. I, too own a model 15 and find it works really well (but, read on...). I've experienced the same problem, but only when the chips weren't being extracted quickly enough and got caught up in the out-feed roller.
As regards the one difficulty I've had with the machine, Powermatic came through - even despite the fact the machine is over 10 years old. Now, how's that for service?! The problem was with the low-speed gear being stripped. They sent me a new transmission, which I'm about 1/2 was through installing. (It's a complex job for a klutz like me).
Good luck with your problem. I'd call Powermatic again and see where that gets you.
Crocusboy
Hi Ed,
Just a knee jerk response ,as I am about to go to work.
I thought Powermatic were part of the venerable framework of Good American Stuff- I think they should be made to solve this problem. Get hold of somebody important there....
The Powermatic 15-inch planers are made in Taiwan alongside of all the 15-inch planers of all brands, almost identical except for color and where they mount the switches, etc. Eight or ten years ago Powermatic added a line of tools for the small shop which were imported, mostly from Taiwan. As far as I know they still make their bigger stuff in McMinnville, TN.
Hey, Ed,
I don't know the Powermatic 15, but most of those indentations look to me as if anti-kickback pawls are denting the surface. That would lead me to check the feed system--start with the anti-kickback fingers to see if they're sticking, then check to see if the table rollers are free, smooth rolling, concentric, and cetera. Then I would also take a hard look at the feed and out-feed rollers for tension, concentricity, etc. If the board moves backwards slightly, the anti-kickback system digs in to prevent kickback. Just a different idea. I think you have exhaustively investigated the chip exhaust system.
Bob
Edited 5/8/2005 5:17 pm ET by Bob
Bob -
I'll check into the anti-kickback pawls. Hadn't considered that. Thanks for the suggestion.
Ed
After reading Bob's post about the anti-kickback fingers, I went back and looked at your pictures in the first post and I think he may be on to something because those fingers have a kind of serrated tip which shows in some of the pictures. Could be sticking or even assembled basckwards or maybe too far above the plane of travel so that they catch on the boards as they pass under them?
Bob suggested the anti-kickback pawls may be marking the wood. I think any marks from the pawls would be planed off but I ran a test anyway. With the machine off I pushed a test piece into the planer while raising the cutterhead slightly so the wood cleared it. I tried to pull the wood back out. The pawls engaged and held the wood in place. Then, from the outfeed side I gave the wood a few whacks with a mallet to simulate a kickback. I raised the head, retrieved the wood and took a photo. My conclusion is that if the pawls are marking the wood I would see a pattern of three dings. I haven't seen such a pattern.
Hello Ed,
There is no doubt that those marks are made by chips being "re-processed"by the cutters and the outfeed roller. This can happen when a very heavy cut is taken-dust extraction or not.
I would also like to see what your chips look like- are they actual curls or are they more like little lumps of broken wood? I ask this because proper chips are lighter than what I have just (poorly) described,and less likely to be cleared properly.
The nature of the chip is determined by, amongst other things, the amount the knife projects beyond the chipBreaker bar in the cutter head- could you let us see a close up of this?
Also, I think you should put the chipDeflector back and position it so that you get the longest "spray" of chips. The job of the deflector is two-fold: to direct the flow of chips and to enhance it i.e. speed it up, so leaving it off may be making things worse.
This problem is solvable- I still think that the supplier should also be pressurised.
Edited 5/9/2005 5:56 am ET by mookaroid
Raising knives doesn’t solve problem <!----><!---->
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In brief, based on suggestions received on Woodcentra.com I raised the knives from the factory setting of 1/16” above the cutterhead to 1/8” or double the factory setting. I ran a test piece of soft tiger maple, 2.25” wide, through the machine at 1/32” depth of cut and 1/16” depth of cut. The dents are still there.
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I measured the knife height above the cutterhead. It’s .065” or approx1/16”. This is about the absolute minimum knife height according to an article I read on Woodweb.com. The knife gauge is designed to set the knives at this value. I spoke with a Powermatic customer service fellow and he confirmed that 1/16” is correct. <!---->
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I also asked about the microbevel on the knives. He confirmed that the microbevel is standard. This agrees with info I’ve received from other Powermatic planer owners. Following up on Lee G.’s suggestion I tried to measure the microbevel fulcrum height to see if it was higher than the knife edge. Using a dial indicator with a round tip I rotated the cutterhead to see if I could detect a bump at the fulcrum. I didn’t see one. However, the microbevel is very small - only 3/64” wide. Perhaps my technique or instrument is not adequate to the task. <!---->
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I decided to raise the knives to a more commonly used 1/8” height. I added shims to the knife height gauge feet and reset the knives. With .031” shims plus a thickness of doublestick tape on the feet, the new knife height was .111” or approx 1/8”. This is double the factory setting. I had to adjust the outfeed roller and the chip breaker heights to handle this changed dimension. The infeed roller isn’t adjustable but it worked nonetheless. I ran a test piece of soft tiger maple, 2.25” wide, through the machine at 1/32” depth of cut and 1/16” depth of cut. The dents are still there. Because the new knife height makes the thickness scale unusable, I’m going to change them back to the factory settings tomorrow.<!---->
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I’m still considering improvements to the ducting, and will research different knife bevel angles but will have to defer any more experiments until more pressing tasks are attended to. If anyone has any further thoughts I’d be happy to hear them. I’ve cross-posted this note on Woodcentral and Knots.
The photo of fluffy shavings was requested by mookaroid.
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Thanks to all who contributed.<!---->
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Ed<!---->
Ed,
I have posted in a previous message here, that I get this with Cherry, on a 15" Grizzly, but not as bad as yours.
I did some tests last night, by moving my dust collector right up to the planer, as I have quite a bit of cherry to process.
I used an anemometer, to measure the air velocity at the pipe (using a test rig)before connecting to the planer hood and played a bit with the blast gate. I used average velocity to calculate CFM, which is not precise, but it's good enough.
Most of my cuts were close to 1/8" to 3/32"
My findings are, that the problem starts at around 820 CFM from the collector. At around 650 CFM it gets real bad. At around 1050 CFM there is no sign whatsoever.
My conclusion is that these machines are dust collector "hungry", not sure exactly what you are using, but if you have a cyclone, try and bypass for a test and see what happens.
Jellyrug -
Thanks for the info. Could you supply more info on your anemometer? I'd like to get some numbers for my dust collector. It's a 2 hp Oneida cyclone with ducting designed and supplied by Oneida. I think it works well but have no objective way to verify that. I've attached a shot of the dc and planer below.
I routinely see dents on cherry, even with light cuts. However, on mahogany I see few dents on heavy cuts and they are scarce with light cuts. So the dents are somehow related to chip formation.
Ed
Ed,
We use anemometers at work, so I borrowed one, unfortunately they are expensive, around $500, you can see one same as I used here.
Your setup looks good.
If you talk to Oneida, they will have charts and if you give them the pipe size, number of bends with sizes and the size of your hood entry (4"), they will be able to tell you exactly how much you can expect at the planer. That cyclone is neat, but it drops the CFM quite a bit. You are losing air due to static pressure loss in the cyclone, the bends, the flex tube and the hood entry.
I believe the Cherry chips hits the chip breaker at the board edges, where there is a gap between deflector and bed. They then deflect into the wrong direction, where some get re-processed.
Try and move your planer right next to the collector and hook up the flex hose directly to the cyclone, to test the difference. You will probably get around 25% more air flow, as a rough guess.
Jellyrug,
Yow, $500! No wonder I don't see these in the Rockler catalog:)
I'll be modifying my ducting at some point and will report back on the effect.
Ed
Any way you could rig a temporary straight-line optimal direct-duct setup, just to see if increasing the CFM helps?
Clay
Hi Ed,
I believe Jellrug has isolated the cause of your problem- if you can get hold of an anemometer you can tackle it methodically.
Then all you have to do is invent a device to give variable suction settings, patent it , sell the rights and make lots of money-then you can go buy a serious spiral cutter planer like SCM Invincible or Wadkin!
Keep us posted.
Mookaroid and Miami,
It will be a while (months) before I will have time for reducting but I will be doing so and will report back. All the ductwork is sealed, caulked, taped and screwed together. I spent several days assembling it and expect it will take a day or two to undo and redo the joints. Meanwhile, I have a lead on an anemometer and may have some cfm figures in a few days.
As an aside I really like the email notification for thread updates that this site provides.
Ed
Ed,
That effort is what I was wondering if you could (for the moment) sidestep. Rather than disconnect all the joints of the glued/screwed/blued/tattooed current ductwork, can you just disconnect the current ducts at the planer and the DC (leaving all the current ducts/cyclone/etc intact), move the planer over by the DC, stick in a yard or so of ductwork for a test, and try that first?
I just hate to see you break down all that ductwork before you determine whether more CFM will even help the problem ...
Good luck,
Clay
Ed -- not only do I have the same planer as you do, but I also have the Oneida cyclone and metal ducting system (although it's the earlier 1 1/2 HP model). However, as mentioned in another post, when I'm planing or jointing and creating a high volume of chips, I also insert a trash-can separator next to the machines to capture most of the chips before they go to the cyclone. (Oneida didn't think this was a good idea, but it sure saves a lot of trips to empty the more difficult to access and unhook Oneida drum.) Even with this extra drop in the ducts, there's enough vacuum to keep the flow of chips going from the planer into the trash can separator without any chip buildup in the machine or on the outfeed roller and, hence, on the planed surfaces. In other words, it ain't likely the lack of air flow causing your problem. With all the trouble you're having, and all of the comments and suggestions you're getting here on Knots, I believe you have to have some kind of unique problem with your machine. It would seem that the best course would be to bear down on company tech support to get at the bottom of it rather than going to heroic efforts -- like getting an anemometer. Especially since it's a new machine!
Jim,
Just curious, have you planed Cherry with a bit of curl in it, at around 8% moisture content, 4/4, a board around 3" wide, taking close to 1/8" cut?
So far, this is the only time I get this problem, I believe the chips are different and they hit the chip breaker at the sides of the board, then end up where you don't want them. The somewhat narrow board, also causes a big air-flow area, between chip breaker and bed, resulting in reduced dust collection effect.
As mentioned earlier, when I bump up to above 1000CFM, the chips are again removed effectively. Problem solved
I looked at his collector curve, and can calculate this, but I'm guessing he pulls in the region of 750CFM on the planer. From my testing, I believe the problem will come and go, depending on the the type of wood and cut.
A 4" port is really only designed for around 450 CFM, a bit small for these machines.
Thanks for hangin’ in, guys.
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Re a quick way to hook up the planer directly to the cyclone, there is no quick way. The duct at the cyclone needs to be slid off the port which means the main trunk has to be slid away by an inch or so. That movement is not possible because of branch lines that are up between the floor joists. Complete disassembly is not needed but I’ll have to break several joints. Sorry there isn’t a quick resolution here. heheh blued screwed and tattooed I think I omitted the tattooed part …
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Re cfm I think the reason for high cfm as recommended by Bill Pentz is to capture fine dust such as escapes from a scms. High cfm is not needed to evacuate planer chips. My former dc, a portable 1 hp unit, captures chips fine. There are no surface dents when the 1 hp unit is hooked up to my old Ryobi 10” lunchbox planer with a shopmade 3” dust port, but using the same 1 hp dc and same board, same depth of cut through the PM 15” machine I get dents. Jim’s setup works as do many others. Mine doesn’t, and a few other guys have reported the same problem. There’s almost certainly something unique to my machine, but what on earth could it be? (Just a rhetorical question.).
I've sent some 14" stock through the machine and got the dents.
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I do notice that a light cut on mahogany is virtually dent-free, all else being equal, so it does have something to do with chip formation IMHO.
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Re going after PM this is still an option as I have a couple months left on my warranty. They have offered (verbally) to replace the unit. It took a 60’ crane and 2 riggers to get the planer into my shop. Removing it and replacing it with a new unit that may or may not work is fairly low on my list of desirable outcomes.
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Ed
Ed,
I really feel for you. Sounds like you went through a lot of trouble to get that planer in your shop. Out of couriosity, why did you need a crane?
I just spent 10 minutes typing absurd trouble shooting ideas. But they were all ridiculous so I deleted them. I'm stumped. Perhaps it is dust collection, I just can't imagine how with that big Oneda.
Mikeplease excuse my spelling.
<<Just curious, have you planed Cherry with a bit of curl in it, at around 8% moisture content, 4/4, a board around 3" wide, taking close to 1/8" cut?>>No, I never plane more than 1/16 at a pass. Too hard on everything for my taste. I have planed narrow curly cherry (made an heirloom cherry and figured-maple chest for some clients a few years ago), but wood that has been seasoned in my shop never gets much below 10% MC as I live in Florida where humidity competes with the temperature needle for degree of deflection. The most trouble I have with this mystery chip denting problem comes when I fail to empty the chip collector in time. As soon as it gets to the top of my "auxilliary" trash can separator the chips will start embossing the outfeed board and I can see the chips building up inside the transparent vinyl collector hose. Also, using the trash can separator probably drops the pressure from the Oneida way below the numbers you guys are talking about -- plus, when I use the planer outdoors with the shroud removed, and no DC attached, I still don't get chip dings. A couple of years ago I planed without a shroud all manner of cherry for a flight of stairs with one landing. I must've swept up and filled up a trash can with chips eight or nine times and never had a surface ding. Last week I planed four 8/4 by eight-inch wide boards -- 8 footers -- down to 5/4 for a pair of doors. It was cypress, a fairly soft, sticky wood about like pine, and no dings. Go figure. That's why I think Ed might have a machine problem.
Seems like this is not uncommon though, a number of us have experienced it. I agree with you, to suck 1000 CFM through a 4" port is a bit unusual.
I hope Ed keeps us posted once he gets his problem resolved, because in general these planers are not complex, only a few moving parts and they work well.
LOL, I see Grizzly's manual suggests fixing the problem with Duct Tape.
Seriously, quote:
Symptom: Chip build up on outfeed roller
Probable Cause: Chips working their way back under the chip deflector
Corrective Action: Lay duct tape over the mounting bolts along the outside edge, to seal any possible gaps
That's their official response? Would fly paper work equally well (I used up all my duct tape on the DC joints)?
I guess that's planer chip damage on your face in the member profile?
No,
Those marks on my face are actually burn marks. There was a thread about the incident, which you can see here.
That explains a lot. I used to use merlot, but then I saw "Sideways".
When I set my planer up with my present system, I had the same problem, and determined that I was not getting enough CFM mainly because that there is too much restriction from the covers on the machine.What I did to fix the problem was to drill 3 - 2 1/4" holes in my dust hood which allows plenty of airflow into the system. Mine is a 24". You may only need two holes.Another thing worth trying is to add a face bevel. If your knives are in the head at 30 degrees hook, or cutting angle like mine, I grind a 20 degree face bevel to drop down to 10 degrees which is ideal for cherry and most other hardwoods. Of course you will need to change the top bevel down by the same amount to end up with 35* sharpness angle.
12 - 14 knife marks per inch is the recommended cut for cherry.I hope this helps, Keith
Thanks to Keith for suggesting these two new things to try. I can temporarily loosen the dust shroud bolts and slide a wedge under the shroud to allow more air into the machine.
Changing the grind is an intruiging option. Someone on Woodcentral mentioned this but I confess I didn't understand what he was suggesting. Currently the knives have a factory ground 40* bevel and a small microbevel. You suggest to back bevel the knives by 20 degrees and lower the bevel angle by 15*. I presume this will produce more of a scraping action and reduce tearout. Chip formation might be different and so chip evacuation might be different. I'll file this in my 'if all else fails' folder along with changing the ductwork. The time to look in that folder is fast approaching.
Ed
It looks like Keith beat me to the punch. It looks like the problem is, in fact, the grind on the knives. They may be "snagging" chips and dragging them across the board surface on the next revoution. Snagging is when the chips get folded over the edge of the knife as it spins. Imagine holding up a sheet of newspaper and hitting it from the side with a broomstick. The paper doesn't tear through, it just folds up around the stick, and gets carried along for the rest of the swing. The same thing is happening with the knives in your planer. chips are getting folded over the edge, and dragged across the board. A different grind angle, combined with proper airflow, will probably take care of the problem.
Tony
Thanks Tony -
Today I raised the dust shroud about an inch on the infeed side (removed two of the shroud bolts and jammed a couple pieces of 4/4/ under the shroud to keep it propped up). I took care to stay out of the line of fire in case something unexpected happened with the shroud partially compromised. Instead of the usual 4/4 I ran some 8/4 maple and poplar thru the machine so there was a good gap between the head and the bed to let in more air. No difference in dents detected with the shroud propped open or in the normal closed position.
The poplar stock, about 4" wide, showed a heavy concentration of dents along the left side of the board. I fed the board into the planer on the extreme left, in the middle, and on the extreme right. If the dents were related to extraction issues, I think the pattern would change when the board was fed into a different area. The dent pattern remained the same. An 8/4 piece of maple tested at the same time showed more uniform random denting when fed in the same way as the poplar. I conclude that the dent pattern is related to wood characteristics more than extraction issues.
I'll send a set of knives out to have them reground. It will take a while to get them back, installed and tested but I'll let you all know the outcome.
Ed
Ed,
What I really find irksome is that PowerMatic is not weighing in here to help with what is an obvious problem. I admire your willingness to try every suggestion to get to the bottom of this. I think by now I would have placed an ad in the paper for a barely used planer. I am very interested in the results of regrinding the blades both in terms of this problem, which I don't think it will solve, and the quality of the cut on hardwood.
Doug
Edited 5/17/2005 11:44 am ET by Doug
I have the same planer but the jet version. I would go through the setup procedure and ensure that all your heights are setup correctly. the chip breaker should be 0.02" lower than the circle of the cut so that the wood piece lifts the chip breaker as it goes through. This will insure that the chips do not get to the outfeed roller. The procedure is in the manual and should be followed precisely. I would not operate the planer without the chip breaker. i do not beleive the hypothesis that the dust collection is the problem, although if you do not use a chip collector you should remove the chute.
Cherry is very suseptible to tearout. You need to be real careful of grain direction to feed direction or you will get this kind of tearout with most any wood.
TDF
Edited 5/8/2005 6:17 pm ET by Tom Ferreira
Tom -
I used to think that the machine needed to be set up precisely. I no longer do.
It was delivered with different height settings than specified in the manual. As I was seeing these dents, I checked the settings and found them to be off. So I set everything to the numbers in the manual. The dents still occured. So I called Powermatic and spoke with a tech there. He gave me a third set of numbers which I duly used to adjust the machine. The dents still occured. Go figure.
The chip breaker is in place. The chip deflector has been removed. There's a photo of it a few posts up.
The dents aren't tearout, they're dents. They can be steamed out with a hot iron.
Ed
Ed,
I have experienced the same problems with my Grizzly 15" planer. I actually thought that it was tear-out, but after hearing of your situation I believe that mine is similar. Your photos are identical to the results I was getting with sharp blades. I was able to run the same board through my 8" jointer and get a perfect surface, then send it through the planer and it looked like yours.
I too have tried everything to correct the problem to no avail. I will need to see if I can steam out the dents though.
Good luck, please let me know if you find the culprit, as it appears your problem is the same as mine.
Steve
Edited 5/8/2005 9:44 pm ET by Steve
Steve, thanks for testifying. Let us know if your dents can be steamed out. I've also received a private email from someone who has the same problem. So there's three of us, at least. :)
There's quite a party going on over on Woodcentral on this topic. Check it out if you have a spare moment. One idea from there, which sounds promising and I will look into tomorrow, is to raise the knives slightly.
Ed:
Thanks, I'll check out the Woodcentral discussion when I get a chance. I won't have an opportunity to attempt to verify that the indentations can be steamed out until this weekend, but I'll let you know what I find.
Jellyrug:
It sounds like there are several of us in the same boat with this. However, I am not yet willing to accept that this is an issue with the cherry alone because I can run the same board through my jointer and get excellent results. I have also tried other woods with similar results.
All:
I did have one idea (that I will try when I have time) to narrow down the list of possible culprits: Plane a board a few times until you know you consistently get the same poor results (light cut), then raise the output feed roller so that it will not contact the board at all. Obviously the board will not come all the way out of the machine, you will need to grab it and hand feed until it's out of the machine (pull the board through from the back side of the machine). Provided care is taken and it is a light cut, it would seem that this could be done safely (after all jointed boards are hand fed). This may get a rise out of the safety police.....
If you have the same dents, the outfeed roller has been eliminated as the source, if they are gone you have found the problem.
What do you think?
Steve
Edited 5/9/2005 10:10 pm ET by Steve
Steve,
The elongated or striated marks result from chips being reprocessed by the knives- they are in the majority in those pics from Ed. The random varied shape marks are embossed by the out roller- if I get achance I will replicate both tomorrow to prove this and post pics.
I only get Ed's problem if I am taking very deep cuts at the higher of the two feed rates my machine has, and the out toller has become dirty, especially with soft resinous woods like pine. I don't have dust extraction on this machine.
Woods like cherry and Makore do tend to encourage the problem- but it is not acceptable. Whenever I have had these marks I have scraped and sanded them away.
Steve -
I've attached a previously posted photo and circled a dent embossed into the surface by the outfeed roller. Note there are no striations and the sides are steep.
Ed
Steve,
I also use the Grizz 15" planer still relatively new and on my first set of knives.
I have the same experience and have checked the machine thoroughly, everything is in specification. I have a 1800 CFM collector connected to this machine and run it via a 6" dedicated line with all other blast gates closed, no difference.
Amongst all the lumber I have planed so far, I only get this with Cherry though, my Walnut, Maple and others are perfect, to the extent that I don't even have to sand.
If I plane a wide board of Cherry, wider than 8" the problem goes away completely.
I have accepted the limitations of the machine and believe it has something to do with the way Cherry behaves in forming the chips.
Ed,
Well sorry to hear your having trouble. As I said, I have the same planer and have not had this problem so I suspect it can be solved. Good luck with it and I will be interested to hear your solution when you find it.
Cheers
TDF
ok, like everyone else, i think i know what the issue is......
the cutterhead is out of true (not round), and it is causing the BACK of one of the knives to hit the wood as it exits the cutting area, bruising / tearing / burnishing the wood.
bruce hoadley, in his book, "understanding wood", shows a picture of this. i think you've got a bad cutterhead - one out of tolerance made the "good" bin. it happens. i would have a tough conversation with the manufacturer or you you purchased it from, and make them check it.
Thanks,Tom. I think an out-of-round situation would create a repeating pattern of marks but the dents I'm seeing are not in any discernible pattern. I have samples with dents that show uniform and very closely spaced (less than 1/32" apart) knife marks. Tough to get a photo of these tiny marks so I won't be able to post an example, unfortunately.
Ed
Ed, your blades are getting dull and will not take the heavy passes you are doing. Take a reduced cut and change your knives soon. Aloha, Mike
Mike,
I wish you were right! The condition has persisted through three sets of new knives. Lighter cuts create fewer dents but they're still there.
Ed
Ed, I sent my message before I had read the rest of the thread. I will say that they look like tears which I have experienced on my own 20 year old Powermatic 18 with either dull knives or when my pressure bar was out of adjustment. It seems like dull knives are not your issue here. Have you checked the concentricity of the knives with a dial indicator? I dont feel that your dust collection has much to do with it all. I dont even know if these newer machines have one. Avail yourself of the help available from your dealer/manufacturer. I would insist on some help in this case or return the machine. Good luck and keep the thread posted on what happens. Aloha, Mike
Mike -
The dents are dents, not tears. They can be steamed out. The planer doesn't have a pressure bar.
Knives are set within .001" +/-. Surface quality is excellent except for the dents. There's a photo in the thread of normal fluffy shavings.
I hired a rigger to move the planer into my basement shop because, for me, it was the best tradeoff between cost and safety. Photo shows my bandsaw, which has just been lifted over the house roof, being lowered into the basement via the outside stairway or bulkhead.
Thanks for trying to wrap your brain around this puzzle!
Ed
Ed and others,
I did try to steam out what I believed to be dents in my boards, and they came right out, so I am in fact in the same boat as you.
Attached is a pic showing a cherry board that has been fed through my 15" Grizzly planer with similar results to yours. It's not a great pic, but all I have at this point.
I haven't given up yet either, but new ideas are scarce at this point. We really need a controlled test with multiple planers, same settings, same wood, same collection. Unfortunately I only have one planer.
I'm going to hook up my air compressor and send a jet of air across the face of the board just in front of the cutter, pointing slightly toward the infeed roller. I'm guessing or hoping that if chips are coming down and being re-cut that this will prevent it. Obviously this would not be a long term fix if it works. It's worth a shot, like I said, kinda running out of ideas.
Steve
Steve,
Thanks for the follow-up. Yep , those are the now-famous dents on your board. Let us know how the air test works. I looked on my machine but couldn't figure out a way to get the air anywhere near the cutter.
Re: directing the air stream, the dents are known in the industry as 'chip recycle'. If I understand it correctly, newly formed chips go around the cutterhead and bash the newly planed surface. Could you try directing an airstream at the cutterhead from the outfeed side? The idea is any chips being 'recycled' would be blown off. Sound wacky?
I should be able to report back with some numbers on cfm in a few days.
Ed
I get the same results with my planer and I then sand out the marks. This is a characteristic of cherry planing-a light/medium density wood subjected to a cutting angle that produces this result. A different attack angle on your planer would change the outcome but I just use my sanding machine after planing. Sorry if I appear to be unsympathetic, I am but have a need to use my planer for all sorts of wood and dont have the time to set it up just for cherry. Maple comes out real smooth with the same machine. Aloha, Mike
As Mike indicated, I also get the "recycled" imprints on softer woods such as cherry and poplar but not on the harder woods. But I have not experienced the the problems Ed is experiencing. Based on other posts about maximizing the CFM's, I'm going to to install a a 7" junction right at the inlet to the cyclone and take it directly to the planer. Even though the dust shroud outlet is only 4", the venturi affect should enhance the chip extraction. If this helps the problem then I will probably look at fabricating a shroud with a larger outlet diameter. I could just run the boards through the stationary drum sander but I would rather eliminate the need.
Doug
Boys,
I said it before, but at the risk of being repetitious, I'll say it again. I get this same problem with my little 12" Parks, only when the dust collector is full, and suction is reduced. Now, I'm not familiar with your machines, but I think you need to get more air going over the cutterhead, and get those shavings out of there. Those shavings are in there rattling around instead of being evacuated as soon as they are made.
Good luck,
Ray
I have the same happening, but when that happens there is chips blowing back out on the infeed table side of the planer. I blow the table off & also give it shot of air into the upper part around the cutter head. It seems to stop the problem for a while. I'm starting to improve my DC system. we'll see what happens. Not a big problem yet, would like to correct it.
JJB
THINKING ABOUT GOING TO SPIRAL CUTTER HEAD.
Ed -- I lightened up your pic for a bit more detail.Leon Jester
Thank you, Leon.
Wanted that bandsaw bad didn't you. I haven't done that yet, I've wanted things so bad sometimes it just eats at me until my feable mind figures out a way to make it happen. Wish I had your bandsaw, but not that bad yet.
JJB
I decided to see what Hoadley (Understanding Wood by R. Bruce Hoadley, Taunton Press 2000, p. 168) had to say about Ed’s problem. He shows a small picture ( fig 9.19 not included here) that looks similar to the ones that Ed showed originally. The related text says (any typos are mine):
“Another common defect that results from faulty surface planning is chip marks. This problem is machine related, not due to inherent flaws in the wood. It occurs when chips are not being cleared from the cutter head because of insufficient air flow or static electricity. Instead, the chips are caught by the knives and then dragged through the region of chip formation, where the cause compression on the surface that has already been produced.”
Given the focus on airflow, perhaps Ed really needs to get the couch-potato electricity up and moving about. ;>)
I don’t know whether a direct grounding strap to the machine might help. But it might be interesting for readers with good/bad results with cherry on their planers to weigh in with the weather or climate conditions in their area (e.g. Good surface/muggy weather).
Also, I searched this site for “planer” and “static electricity,” and message 17750.11 mentions misting wood before planing, and even using fabric softener to avoid surface defects.
Hello again,
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I bought a cheap Anemometer and measured dust collector airspeed values at my planer and, just for fun, a few other sites.
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First, the numbers:
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At the planer 4” dust port, 8,400 feet per minute (fpm) and calculated 733 cubic feet per minute (cfm).
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At the planer 5” hose which connects to the 5” to 4” reducer, 6,200 fpm, 845 cfm.
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Second, just for fun, some other readings:
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The ducting to my jointer is the same distance from the cyclone as the planer, shares most of the ducting with the planer, and has a slightly straighter run. At the end of the 5” flex at the jointer I’m reading 7300 fpm, 995 cfm. It’s amazing what a slightly straighter run does for readings! Compare the planer at 845 cfm. I’m encouraged that if I rearrange ducts to get a more direct route from dc to planer and put a 5” or 6” port on the planer I should easily be able to exceed 1,000 cfm.
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How about some numbers for my former dc, a 1 h.p. Reliant? It is equipped with empty and reasonably clean <!----><!----><!---->Oneida<!----><!----> upgrade bags. I used to operate it with a 10’ length of cheap 4” flex hose connecting it to whatever machine I was operating. There’s a 90 degree pvc elbow connecting the fan outlet to the flex. Measured at the end of the flex hose, 4700 fpm, 410 cfm. Measured at the fan intake (hose removed), 8000 fpm, 698 cfm. That flex hose and elbow sure chew up the power, eh?
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Third the measurement procedure and some comments:
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The anemometer conveniently is supplied with a lanyard. Firstly, I put the lanyard around my neck so in case the instrument got sucked into the ducting it wouldn’t go too far. I measured the air speed at the rim or edge of the fittings where I found the lowest values. Airspeed went up if I measured in the middle of the duct opening, but I believe this is at least partly due to the anemometer body restricting airflow and increasing velocity, i.e. the venturi effect.
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The anemometer is accurate +/- 3% according to the maker. I don’t think the numbers I’m reading are absolutely accurate but believe they are reasonable ballpark figures which are in line with expectations for my dc, a 2 h.p. cyclone. The anemometer is rated for a maximum velocity of 7,800 fpm. I read this in the instructions after I clocked the 8,400 fpm reading on the planer. So just an fyi if you’re thinking about getting an anemometer; this model is about maxed out on a 2 h.p. dc. From what I’ve read one can get accurate static pressure readings by using a manometer. For readings inside a duct it’s the only practical way to proceed. Bill Pentz has much info on this on his site. I went for instant gratification with the anemometer.
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Fourth, responding to a recent post from Bob, thank you VERY much for the reference to Hoadley. Them’s the dents alright. Currently the shop is 50% relative humidity. It varies from 40% to 60% throughout the year. Haven’t noticed any static electricity. Nonetheless I’ve tried moistening the stock but it had no effect on the dents.
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Fifth, following up with Jellyrug, first of all congratulations on so accurately estimating my planer cfm at 750 cfm. My calculated value based on velocity is 733 cfm. Also, thanks for mentioning your anemometer. It encouraged me to do similar testing.
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Sixth, some tentative conclusions. From reports posted here and on Woodcentral, some people get the dents only if their dc clogs or overflows, some get dents when operating on a dc but the dents do not appear if dust shrouds are removed, some get no dents with marginal dust collection, some have no dc and get no denting, some (including me) get dents under all conditions. My conclusion, with apologies to Mr. Hoadley who I hold in high esteem, is that dust collection; cfm etc has nothing to do with dents. If you disagree, please reconcile the empirical evidence above. I may have to apply 1100 cfm to my blasted planer to eliminate dents, as Jellyrug suggests, but I think this is overcoming the problem by massive force and not by identifying and correcting the root cause. Sort of like when you’re rolling your shop vac across the floor and it hangs up on a tiny wood chip under a wheel. Yes, a mighty shove will get it going again but the problem is not that you were pushing too weakly; the problem was the tiny wood chip. In the case of the planer dents, I don’t believe the ‘tiny wood chip’ has been discovered.
This is cross-posted on Woodcentral.
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My thanks to all,
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Ed
Ed,
Very interesting.
At first I laughed at the Grizzly manual, but after thinking about it, it's not such a bad idea. I don't have time, as I'm really trying to finish a rush job here, otherwise I would give it a try.
They suggest duct tape, taped over the chip deflector (the red plastic one), so that the duct tape actually only just touches the knives. Means you close that 1/8" - 1/4" gap between the knives and the chip deflector. May sound like a space rocket, but it will prevent those little chips from being re-processed.
Anyway, if you suck another 200 CFM through that baby, you will be home safe, even although it's over the top.
Thanks, Jellyrug. Good luck with your current work.
I elongated the adjustment slots on my chip deflector so it was within 1/64th inch of the knives, and no effect on dents noticed. Next time I have the shroud off I'll adjust the chip deflector so it touches the knives.
Ed
Is the dust collector getting close to full? If it is, it won't have the same suction. Also, if there's a cloth bad on the DC system and you have been using it while it's damp, the cloth may be getting clogged. Mine wasn't pulling as well as usual and I grabbed the bag when it was off and the cloth was suddenly a lot thicker than normal. I shook it and the fine dust fell off, clearing the way for the air to escape. If your shroud has a second port for running the ducting to another machine, there may be a buildup that sheds some of the larger chips, or if the second port is open, there's a lack of vacuum.
Also, how long since the knives were sharpened/honed?
"I cut this piece four times and it's still too short."
Edited 1/12/2006 12:50 am by highfigh
Hi Ed.
I have a 15'' Grizzly planer, It will do the same thing on pine if i try to take too deep a cut . I think it is caused by wood chips on the outfeed roller. the chips are not getting away fast enough. I planed some walnut for a friend a while back it did the same thing, but the wood had about 16% moisture content. that might have had something to do with it.
Have a nice day Lee
Hello to all,
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By coincidence I’ve been working on my final report on my planer problem. Since crocusboy has restarted the thread, I’ll post the report now.
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Back in May 2005 I posted on this board about poor surface quality on my Powermatic 15 planer and asked for suggestions for a fix.
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Many suggestions and opinions were put forth as to the cause of the problem and possible fixes. I’ve summarized the suggestions at the bottom of this post so you don't have to read through the entire thread again. The problem was identified as ‘chip recycle’. Back in May I tried most of the suggested fixes without success. There were 3 suggestions that I needed time to test: back-bevel the knives, increase dust extraction (cfm, cubic feet per minute), and remove the factory micro-bevel.
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My experiments are complete and as promised I’m posting my findings. In summary, the planer now produces acceptable surfaces.
Because it was the cheapest option, I first tried 10 degree back-beveled knives. I counted chip recycle dents on a piece of wood planed with factory grind knives and the same piece of wood planed with back-beveled knives. The back-bevel knives had more dents than the factory grind, 15% more in one test. Also, the back-bevel grind had no micro-bevel on the bevel side. I’m confident the micro-bevel is not causing the chip recycle.
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Finding no joy with the modified knife grind, I revised my dust collector ductwork to increase cfm at the planer. The original path from cyclone to planer was over 20’ long, ending at the 4” stock dust port. With an anemometer I measured 733 cfm* at the 4” port. Almost all reports I’ve received indicate that 733 cfm is more than adequate to clear chips and avoid chip recycle. Nonetheless I wanted to try a higher cfm.
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I turned the planer around and modified the ductwork to reduce duct length to about 10’ and routed a 6” duct to the planer. I had a 6” port fabricated locally ($160) to replace the stock 4” port. The planer now has 1,100* cfm at the dust port.
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Results are acceptable but not ideal. At 1/16” depth of cut the chip recycle dents are much reduced from earlier tests but still present and unacceptable. At 1/32” depth of cut the chip recycle dents are almost completely gone. Earlier tests at 1/32” showed fewer dents than at 1/16”, but still unacceptable. Many boards of different species show no dents but I do occasionally see one or two dents on a board. Also, if I send a board through against the grain I still get heavy chip recycle dents (but very little tearout) on common hardwoods.
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It occurred to me that there might be insufficient airflow through the planer to support 1,100 cfm so I cracked open the dust shield on top of the machine to provide more air. No difference in surface quality was detected.
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Below I’m summarizing the suggestions from earlier posts so you don’t have to read through the entire thread to refresh your memory. Please read through the summary before posting any further suggestions.
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All my testing was at 1/16” depth of cut and 16 feet per minute. Surface quality has always been excellent (no tearout, virtually undetectable planer ripple) except for the dents. Common North American kiln-dried hardwoods were used for all tests.
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The suggestions to date, and outcomes:
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1. Send the planer back and get a new one. Powermatic did offer me a new machine. As I needed a crane to get the planer into my shop I’ve opted to try repair rather than replacement.
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2. Insufficient cfm, insufficient chip extraction. The original setup had almost double the recommended cfm (733 vs 400) with poor results. The revised setup has almost triple the recommended cfm and yields acceptable results.
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2a. Insufficient makeup air. I tried wide boards, narrow boards, thick boards, thin boards, and cracked open the dust shield on top of the machine to overcome any lack of makeup air. No improvement noted.
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3. Too much cfm. I tried planing with no dust extraction (and the dust hood off). No improvement noted.
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4. Dents are caused by chips on the outfeed roller. Dents caused by chips on the outfeed roller look different than the chip recycle dents. There are photos of the two types of dents in the thread.
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5. Machine out of adjustment. The problem was present from day 1 with factory settings and persisted through several adjustments to the settings.
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6. Knives dull. Three different sets of knives were tried, plus a back-bevel set. No improvement noted. Surface quality has always been excellent except for the dents.
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7. Chip deflector problem. I tried various settings of the chip deflector including complete removal and found no improvement. The only thing the chip deflector seems to do is make noise.
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8. Anti-kickback pawls are damaging the surface. I looked into this and decided it was not the cause. More details in earlier posts.
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9. Knives are too low. The knives are set to 1/16” above the cutterhead. I doubled this to 1/8” and observed no improvement.
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10. Needs pressure bar adjustment. No pressure bar on this model.
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11. Static electricity. I checked the entire machine. Everything is grounded and I’ve never observed any ‘static cling’ on the machine or stock.
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11a. Humidity too high or too low. Shop humidity ranges from 60% in summer to 30% in winter. No difference in surface quality noted.
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12. Different knife grind needed. Tried this, no improvement noted.
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13. Remove the microbevel on the knives. Tried this in conjunction with the back bevel test. No improvement noted.
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* Because of my crude measuring method this is not an absolutely accurate number but it is in line with expectations for the cyclone which is rated at 1,200 cfm.
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My goodness, you have spent way, way more time and effort on this than could ever be justified. If the planer was having that much problem you should have thrown it away about 18 "observations" ago, unless you're being paid as a research scientist for Powermatic.
Mark -
Having asked for and received help from this group, I felt obligated to look into their ideas and report back.
Ed
I have a similar problem - although much less severe - with my jointer. Actually I realized that its only if I use one side of the blades (the end closest to the pulley) if I have the fence set to the right about an inch or even less then the problem is gone. Although I have not actually had the time to check my guess is that one of the knives is tilted slightly and a little higher than the rest. Assuming that that is in fact the cause perhaps for some reason one of your planer's knives is a little proud of the rest?
Wannabee -
You are correct that chip recycle can be caused by a heavy cut although from my testing I'm convinced that there are other causes as well. If you reduce your feed rate your chip recycle problem should go away.
For my tests knife height was very good, +/- .001" as measured with a dial indicator. In earlier posts there are images which show excellent surface quality (except for the dents).
Ed
Nice work. Thanks for sharing what you found!My goal is for my work to outlast me. Expect my joinery to get simpler as time goes by.
It's late in the thread, but I'll share what I discovered with my 15" Powermatic. The chip impression most often occurred when the boards were 11" to 15" wide, and was usually accompanied by a clogged discharge chute ..... not the root cause, but it forced me to shut down and clean out the path.
If you unplug and open the machine up, place a narrow board in the pathway and observe all the open space for the dust collector to draw air into the cutting area, and note the pathway that air will have to take on it's way through, picking up all the chips and going out the exhaust chute. Now place a wider board in the pathway, similar observation .... and finally look at a maximum width board. Quite a difference. With the wider boards, the airflow path is disrupted, actually reversed in some areas, resulting in recirculation of the chips beneath the outfeed roller, with some, more than likely actually recycling past the cutterhead. Wouldn't it be interesting to watch a video of this sequence. I described this to the Powermatic people, before they closed the McMinnville, TN plant, but they offered no suggestions ..... after all they had just sold out to Jet, and they were history! The angled 4" port on a friends machine simply compounded the problem, but fortunately, mine was one of the last straight ones!
In the end, it comes down to maintaining the airflow (velocity), WHILE UNDER OPERATION, and this will entail providing spring-loaded alternate air intake gates properly located in advance of the cutterhead, possibly in the sides of the machine head. I built a plywood replacement hood with some "relief ports" which slightly improved the situation when I remembered to open them before starting the wide boards through (I plane a large amount of 12 - 15" wide cherry and walnut), but it did not cure the problem. I'm hunting for a 24" machine now, and will keep the Artisan 15" for smaller and thinner work, with the stock hood. My dust collector is nothing more than a large (Sears) shop-vac, pulling through a home-made metal can/cyclone collector, fashioned using old shop vac accessories, so I can't be too critical of the machine!
Good luck with your continuing saga .... however, It's my belief the space inside that machine head is too limited to provide enough air, headed in the right direction and at the necessary velocity to carry the chips out. It's the price one pays for the ecomony of size and cost they offer over the industrial machines .... which Powermatic did a great job of, before being sucked into the Asian product market.
John, back in Texas
One other possibility to consider: I just finished planning thousands (literally) of linear feet of poplar & beech to build a 24 x 32 building -- no plywood except for the subfloor. Boards ran from 2x4 to 2x12. Many 16 feet long & most went through the planer a minimum of 5 times (next time I'll buy lumber for my building projects!). I had tremendous problems with chips getting backed up in the planer (Delta 15 in). The backups permanently reshaped the outfeed roller. My dust collector is about 1150 cfm & nothing I tried would help with the problem. As a result, I rolled the planer to the door of the garage & just let the chips eject onto the ground. The cause of the problem became obvious very quickly......6, 8, 10, 12 inch long chips coming off the boards don't fit very well through a 5 inch dust port when they hit it broadside.If you can, I suggest you run some boards that have caused you problems through your planer and see what size chips are coming off. Some of my wood was a bit green and they were the worst ones at creating long chips, but even the wood that was thoroughly air dried would cause problems, depending on depth-of-cut, grain orientations, etc. (hmmmm, is it time for a new planer w/ those carbide inserts?)
Good Observation! There is quite a gap at the throat, and with damp lumber, I'd expect some of that. My cherry and walnut is 18 to 25 years air-dried indoors, and I've had no evidence in the chip collector of elongated shavings. Ed's impressions were short, as we all get when the outlet clogs and it blows back out the infeed side. That's just a case of too much volume for the 4" port to pass .... and I slow the feed rate to the lower speed .... which doesn't help sometimes, due to the airflow pattern inside the machine. As I said, we expect these $1000 machines to perform like those $2500 models I/we can't justify, and they aren't up to the task!
John in Texas
Tailsorpins,
I'm not sure we have the same model planer. Mine's shown at this link:
http://www.wmhtoolgroup.com/index.cfm?area=shop&action=detail&iid=12382
Makeup air is certainly important. While I haven't measured cfm under operation, I've tried various thicknesses and widths of wood and have opened the dust shield on top of the unit to assure sufficient makeup air, with no improvement in surface quality.
Like you I wish there was a way to get a slow-motion video of the chip flow to see what's going on.
Ed
Yep. We have the same machine, except my chip chute is straight out the back, and more recent ones were angled to one side. Have you ever laid a straight edge over the three rollers and discovered they aren't even in line .... the center one is higher. When they punched the holes for them in the tapered support bars, it stretches the metal on the top/thinner side resulting in them being crowned. I've considered removing the outer one and getting by with just two, but never have.... I just lined up the two inside ones and act like the outside one is not even there. My son pointed out that there's a new model showing up on the internet sales houses that has solid, cast iron infeed and outfeed tables .... each appearing to be at least 12 to 16" long. Now that's an upgrade I'd like to have!
For now, I just run the slowest feed rate, 1/3 revolution advance on the cut, and live with it! Had to replace the double sided knives finally .... wish I could afford a set of carbide .... but that's just dreamland for now!
How do you like the depth-creep that seems to occur if you don't lock down the table? I cut off half of the crank handle, wired in a lead counterbalance, and it still did it! I finally fashioned a depth lock from an old hasp, that engages the space between the handle spokes, and cured that. Don't even have to lock down the table now .... suspect that puts a lot of pressure on the chain, but it works. I'll post a picture of that modification if you're interested ..... Time to get back into the shop.
Later,
John in Texas
John -
Yes, I notice the same thing on the I/O rollers - the middle one is high; 1/64" and 1/32" respectively in my case. Getting the I/O tables on 'straight' was the most difficult part of setting up the machine.
I haven't seen the creeping depth wheel business you mention and I have dozens if not hundreds of hours of time logged on my planer and another like yours with the straight chute. Glad you eventually found a workaround. Typically I leave the post locks loose until the last few passes when they are tightened to eliminate snipe.
Ed
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