About six months ago I purchased a contractors tablesaw (General International). At the time I was very impressed with the out of the box adjustment of the miter gauge, fence, etc. and made a few ripping cuts without any problems. I build a crosscut sled and made a number of nice cross cuts of 1 1/2 inche stair treads. Perhaps a few more cuts.
Now, more recently I bought a new plywood blade and went to trim down some 3/4″ birch plywood. This cut burned the edge pretty badly. So I adjusted the fence to eliminate the burn. I thought this odd since I did not have a problem months before. I thought that was the end of the problem.
I then went to cut some 1 1/2″ stock and had a slight burn again!
So I started to check things out. First I checked to see if teh fence was parallel to my miter slot. All was well. I then raised the blade all the way up, moved the fence over to almost touch the blade. With a feeler gauge I checked to see if a blade tooth close to the front had the same clearance from the fence as a tooth in the back. All looked good.
Then I lowered the blade so that only a 1/2 inch or so was showing above the table. I then moved the fence in and check the teeth as before with a feeler gauge. The tooth at the back of the blade was considerably closer to the fence than the front most tooth!
HOW THE HECK CAN THAT BE! Blade square to the fence when raised, and off when lowered. Ok, perhaps more importantly, how the heck do I fix it?
I hope I have explained the problem clearly and hopefully someone has seen this problem before.
Replies
Hi,
I'll give this a shot purely as a mechanic. I don't see any mention of the blade's position with respect to the miter slot or the table surface. I think you need to not worry about what could have happened (you may actually figure this out in the process). Start with the basics (and get the actual steps from someone smarter than me, from Tolpin's Table Saw Magic or another article on adjustment). Using a dial indicator may be best, but you can get away with a thin nail mounted in an arm of some sort as a scratch gauge.
I may not have these in order...
Remove the blade and check the arbor for runout.
If OK, install the blade, move the fence out of the way and check the blade for runout. If it is bent or mounted improperly you will get false readings.
Align the motor and trunion assembly to the slot. The arbor must be perpendicular to the slot for the blade to be parallel to the slot. Do this with the blade high enough to get the most distance between the front and the back of the blade. Once parallel, repeat the check with the blade in the lower position. You may find you have some twist going on as the blade is lowered. You could have something as simple as shavings obstructing one side of a pivoting mechanism, in a track or slot, or between a limiter and a set screw, restricting the motion of one side and causing twist.
Check the face of the fence to make sure it is not twisted.
Adjust the fence parallel to the slot.
Adjust the fence face perpendicular to the table surface. Check in several places to confirm no twist.
I am sure something's missing, but that might be a start.
Lawrie
Lawrie,
Thanks, most of the things you mentioned I have checked. Fence parallal to the miter slot (and hence parallel to teh blade when fully raised), fence perpendicular to the table, and blade square to teh table. As for runout; when the blade is fully raised I have used low tech tricks to test the same tooth at the front and then when it is rotated t the rear.
The key word in your post I beleive is twist. This problem has mystified me since the raising and lowering mechanism run is a plane, it is not a three dimensional adjustment and thus SHOULD not be able to be parallel to the miter slot at one elevation and not at another. Now the key word in my last sentence is SHOULD. LOL!
I think I will start over and start by seeing that the blade is mounted cleanly (no dust behind the blade near the arbor). Secondly,clean the gogs in the arbor adjustment (I think you call the gear like teeth cogs).
Thanks again. For at least sharing a bit in my mystery and frustration.
What plywood blade are you using? Is it carbide?
Also you might contact Forestgirl on the board. She has a link to a file for instructions on how to adjust the trunnion of a contractor saw. The two rods can get out of coplanar and would likely cause your problem.
Delta has instruction on their website but you have to dig for it. This is a major weakness of a contractor vs. cabinet saw design. Not that you can't do good work with your saw, but you have to check and adjust much more often.
Edited 5/21/2005 9:31 am ET by adastra
adastra, What blade? Well, it does not really matter. It is a F80 Freud blade, but the problem has occured with my carbide DeWalt 50 thooth blade as well. So the problem is likely not the blade and likely not dirt or dust around the mounting arbor either (although I will clean the snot out of it now).
I am leaning on fine sawdust being the problem. I did cut some MDF, and the dust from the plywood is also very fine. Last night I took a quick look under the table and there is diffently some packed in dust.
Blade? Well I just thought if he was using one of those high speed steel blades that are center ground that its very hard to get a cut without burning. They dull quickly and there isn't much clearance from tip to plate.Thats all.
For that alignment, here, the BLADE PLATE as close as possible to the teeth is used, but not AT any tooth, and the blade is raised as high as possible, to get the most verification distance from entry of cut to end of cut.
That's because teeth design make referencing to them more difficult than just refering to the blade's face, and also because individual teeth might vary, even minutely, as far as offset, be it from manufacturing, grinding, use, or abuse.
-mbl-
mbl, sorry I am having trouble with your first sentence.
"For that alignment, here, the BLADE PLATE as close as possible to the teeth is used, but not AT any tooth, and the blade is raised as high as possible, to get the most verification distance from entry of cut to end of cut."
What is "that alignment"
you say "here, the Blade Plate as close as possible" ?????should that be "the blade plate SHOULD be as close as possible
thanks for trying.
Sorry to be unclear.It means for alignment the teeth are not used, the body of plate of the blade, just short of where the teeth grow.You mention you are using the teeth of the blade to verify alignment, that's why the comment was made.Some blade makers sell a blade-disk (no teeth) to align, so the teeth are not on the way.Also, the thicker the plate of the blade the better, meaning thin-kerf blades for alignment are second choice.-mbl-
mbl,
Thanks again. I have considered teh tooth issue. So I check the plate, I check different teeth, I check the same tooth front and back etc..
The problem is I am not looking for 1 1000th, but ten. Same tooth, different tooth, blade body, don't make much difference when ALL TELL YOU THE SAME THING and you are looking for 10/1000ths.
Thanks everybody.
10/1000th = 1/100th the kerf of the F80 is .126 I have a sinking feeling that 1/100th of an inch out of alignment is not the problem. I'm going out on a limb here and suggest that technique is more likely the culprit.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
I think so too F.G. It burns more on deeper cuts, and with a ply wood blade. Sounds like normal stuff to me. Both of those senarios cause more burning under all conditions.
Mikeplease excuse my spelling.
Well, it may be good to hear that 1/100 of an inch in heel may not be a problem. I did read that more that 12/1000ths or 1.2/100ths is a problem. So maybe all is well.
As for your technique comment. Seeing that you did not offer any details, that sounds more like a juvenile slam than a helpful tip. They do say that growing old is a requirement, but growing up is an option. At any rate, if your technique-nothingness-comment refers to fed rate that could be the problem. Some other poster mentioned the increased tendence to burn with a higher tooth count. So . . .
If your comment refers to running tight to the fence rather than wobbling and pinching the blade, I could say "I don't think so" and risk all sorts of replies, helpful and otherwise.
If your comment refers to alignment technique, I had an airplane mechanic bring his measuring equipment over and confirmed my low tech measured deviation of 10/1000ths.
So, I either do have an alignment problem or a technique problem. Ok, now that we have established that . . . LOL! And since I did not have any preceived problems cutting 2 by stock or 3/4 inch ply with my combination (50 tooth) blade and only started burning with the plywood blade, I am leaning on feed rate/tooth count as the issue.
If any one is interested any more. I certainly am getting bored.
All, my comment was definitely not a slam. Simply visiting another possibility since there had already been a ton of discussion about alignment and such. Sorry if it came across that way, not intended. Also sorry you're bored. These kinds of problem certainly can be frustrating. Feed rate/tooth count might be the problem I guess. Good luck.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Thanks Forestgirl. As for being bore, it is not the board. I believe we learn things on these type of boards even when people misunderstand a question and so anwser a completely different "question". Can be frustrating when you are trying to solve a prblem, but often educational.
Bored? Well, maybe the wrong word. I am just ready to move on and get working again. I have been away for a few days, so don't think this issue has derailed me for a week.
I guess there is only one question. Is a 1/100 inch heel a problem? If not forget it, and focus on the feed rate.
Sorry to hear no obvious problem has shown up here. Re: Adastra's comment about the carriage being out of parallel, it'd be incredibly weird if that was the problem here, given how new the saw is (and that it's a General!). That problem generally occurs when someone jams the motor into an outfeed table when tilting to 45*, or the saw is dropped or something like that. In my experience, the symptom is that the blade can be set parallel when at 90* but way the heck off when tilted to 45*
Given General's reputation, I think I'd call them and run through the situation.
I have one bone to pick with you over your tune-up procedure. It appears that you are referencing the fence to the miter slot, then the fence to the blade and then the blade to the miter slot. This is pretty bassackwards to me. IMHO, you should first check the blade:miter slot alignment, then the fence to the miter slot. This is your most reliable measurement, as it covers a much longer distance that fence:blade and will show very small discrepancies.
Before you check the blade:miter slot, confirm that the blade is 90* to the table.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the "I Rocked With ToolDoc Club" .... :>)
WOW, forestgirl, either I am a much better writer than I think or you are very preceptive! Yes, I did first confirm (not check or align) that the fence was parallel to the miter slot. This is naturally very very easy to do and since the saw had been working fine before it seem like a simple way to confirm that the fence was not wacked out. And since the blade had been parallel to the fence when the fence was parallel to the miter slot, it was also an easy way to secondly see if the blade had changed postion. Follow the logic.
Had I been setting the saw up out of the box, I would have "aligned" the blade to teh miter slot first.
As it is, I did first confirm that the fence was still parallel t the miter slot, and then confirm that the fence was parallel to the blade when fully raised. All was parallel. When lowered, the problem appeared.
Then I did a second check, using the miter gauge and a dowel rod clamped to the miter gauge to do a low tech runout check. Again, all was well when the blade was raised and screwed up when lowered.
The results of both reviews of the problem were the same.
I don't mind you picking a bone wiht me as I don't claim to know all that much about these things, although in this case I am not sure your bone held water and qualifiies as a bone. LOL!
Thanks again. I will start one more time with a cleaning. And then probably make some phone calls.
It all did come out in wash, admittedly, but checking the fence-to-blade alignment can be misleading because it can appear parallel when it isn't. Hence skipping that test altogether (see Mike's post).
I do the same as you when a problem suddenly crops up, first checking the fence alignment. But when it becomes obvious there's something weird going on, I start at the very beginning of the whole alignment process and check everything in sequence. Just my routine.
I sure hope this turns out to be an easy fix. Contractor saws can be a pain when they get freaky. I'll have to think about a bone holding water,L!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
I have heard of this problem before. It seems to not be uncommon with contractor saws. First of all when you say "the blade raised all the way up" do you mean all the way untill the wheel stops turning? Even the best cabinet saw skew when you top out the adjustment. What happens is after the stop on the trunion hits the table the slack in the raising mechanism binds and lifts the trunion. So, when checking your settings raise the blade all the way, then lower it about a half turn. If you really want to get anal lower it a whole turn then raise it a half turn to eliminate backlash. (You should always raise the blade to its heigth" Even if you are not raising the blade all the way it would not suprise me if there was a variance between the high and low settings of the blade. General makes a good saw, but it is still a contractors saw.
Now, more importaint than all that is that you could probably get better alignment from diffeternt adjustment methods. You could never get reliable measurements between the fence and blade, especially with feeler gagues. Instead align the blade with the right miter slot. Make a simple jig using your miter gauge, scrap wood and a screw. check this picture of a jig using a dial indicator. http://users.zoominternet.net/~frazer/Wood/algn_jig_blade.jpg
Instead of a dial indicator you can use an panhead screw or a nail in the end of a scrap piece of wood clamped to the miter gauge. Then use the feelers to measure the difference between the same tooth of the blade at the front and back of the miter slot and adjust the trunion untill there is no measureable difference. If that description is unclear look for a book on machine maitinance, or search on this site for a better description. Once this is done it is easy to your fence parallel to the miter slot. I dont use any tools other than my fingers, simply sliding the fence over untill it is even with the edge of the slot, then I can feel with my fingers if it is even at the front and back. I think that any on can feel a 1/100" with their finger tips. check all these measurements before every project to make sure it hasn't changed. After you have had the saw a while you will get a feel for how well it holds its adjustment.
Also is the blade of good quality? ($50 or more). If the blade isn't straight then your measurements will vary based on how the blade is oriented.
Bla Bla Blaa.
Hope this helps,
Mike
mike,
Thanks.
Yes, all the way up but not hard up. And I think you misunderstand the problem. The blade appears very close to square when completely up. It is off when it is lowered.
People can be critical of a low tech approach, BUT FOR GOODNESS SAKES FOLKS!, if I have burning SOMETHING IS WRONG and if a low tech approach CONFIRMS the problem test after test after test; then the low tech approach confirms the problem; whether a higher tech techique is ultimately necessary to make the alignment. One thing at a time.
As for your jig approach, as already posted . . . already done it.
Yes, high quality blade. Freud, F80.
Funny... After re-reading the post I realised that we may be missing the obvious things regaurding the burning. The higher the tooth count the more likely you will have burning, more teeth equals more friction. This is seldom a problem with sheet goods, but if used for ripping or thick croscutting they will definately burn. Regaurdless of what so many claim a 1.5 HP motor slows down a lot when cutting hardwoods over 1 inch. I think that if the burning is worse on 1 1/2" thick stair treads (hardwood I assume) it is as likely to be due to the slower blade speed and feed rates as the out of squareness. I really don't see how dust build up could cause burning, and I doubt it would cause miss-allignment.
I assure you that I am not bashing the low techness of you methods. I am only sugesting the you use the same measureing methods differently..... Or something like that. :-) There is no good way to measure the blade allignment to the fence. So give the miter slot method a try. I realize that this will not solve the out of square problem as the blade is raised. BTW does the blade more out of square relative to the fence or the table top? When I've seen this is was relative to the table top. So that instead of cutting at 90 degrees it would cut at 91 degrees. this would not cause any more or less burning. If the blade is toeing in (or not remaining parallel to the miter slot) as you raise it this would cause burning. Unfortunately there is likely no remedy for these problems. It could be caused by the two trunions not being in allignment, I've heard that it is very, very difficult to allign them. However it is more likely that it is caused by the trunions flexing under the weight of the motor and itself. If most of your cutting is under an inch then I would shoot for good allignment there.
Hope this helps,
Mikeplease excuse my spelling.
Hey Mike,
Thanks so much for the reply. And although it appears that you did not get all the details of my original post correct. (Example, you mentioned my problem burning stair treads. I had no such problem there. And you mention my problem of being out of square when the blade is raised, but the actual problem is being out of square when lowered.) LOL!!! Oh, the problems wiht message boards. Or the problem with the English language.
As for the use of a fence to measure heel, I GET IT. Again, it was a GROSS, EASY, first check. And as much as everyone has hammered and hammered on it, I got the same 10/1000th of an inch deviation that way as I did with the block of wood and screw in teh miter slot, and the same as my mechanic friend. Not that stopped looking based on that measurement alone. However, had it shown that the blade was square, it might have gone off in a different direction. Anyway, Nuff said, . . I would hope. LOL! Certainly, we all understand the potential problems using the fence.
But your point about the tooth count and more frition sounds nuts on! Makes alot of sense. And since I did not have the burning wiht my 50 count blade . . .
Thanks everybody!
All,
I guess I picked up the stair tread thing on another thread. I understood the out of square at the top comment. I am just looking at it from the other way. We generally set the blade when raised all the way. So that is the reference.... as you lower the blade it deviates. In Forrest girls defence In the 2 years or so I've been here she has never slamed anyone.
Also the blade cuts more effeciently as it is raised. The higher the blade the fewer teeth in the cut therefore less stress on the motor and less heat. The trade off is that you are more likely to get tearout, mostly on crosscuts. But burning is seldom a problem on cross cuts.
Mikeplease excuse my spelling.
All in the ear of the beholder I suppose. Or perhaps I was having a bad day. All is well!
The blade is square when fully raised. It is off when lowered, and I do hear the blade cutting wood as it is pushed past the back edge of the blade. I don't like it, but we will see if I will try any adjustment. As you can tell I have been spending more time talking with people on this board about it than spending time in the shop! LOL!
take a dial indicator check and see if the blade is warped. If not then check the arbor flange for burrs, no burrs set your dial ind. up and take a arbor flange run out.
start from the end and work your way back. Best way to troubleshoot :>)
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Blade(s) flat, arbor could not be more beautiful!
> Also is the blade of good quality? ($50 or more). If the blade isn't straight then your measurements will vary based on how the blade is oriented.
All blades have a certain amount of warp and wobble to them.
Start by unplugging the cord or locking out the power. Raise the blade just short of all the way up. Set the dial indicator to run on the side of the blade out near the teeth. Gently turn the arbor by hand -- not touching the blade -- and watch the needle move.
There'll be at least a couple places where it stops going one way and starts going back again. Near one of these turning points, you'll find the largest area of constant needle position. Draw a circle around it on the blade with a sharpie, and use the circle for your measurements, turning the arbor to get it where you need it.
-- J.S.
Check to make sure your table is flat and that the trunnions are tight to the underside of the table.
A BAD BLADE? Try a different blade and see what happens???
Same with two different blades.
Thanks.
Check to see if the trunions halfs are tight together. A looseness between the two halfs could allow for a lateral shift when changing blade height. Check out John White's book " Care and Repair of Shop Machines", pages 77-78 for info. on clamping trunions together for alignment purposes. Also check out cool jig to align miter slot/ fence parallel to blade. A $6.99 HF dial indicator and a couple of scraps. This is the one we use to teach table saw alignment. John, I have done it again, plugged your book. With Fathers Day right around the corner, wouldn't you rather have a book, than another tie? Only about $20.00 and worth $$$$$$$$$$$$$ more! This is the book that I refer to first on machine problems.
Hate to bring up an old thread, I've got the same problem as original post. Getting ready to break free the nuts on the tie rods
How many times has this saw been moved? If it has been, were you the only one to move it? If you had no problems before, did the burning start after someone else moved it?
My saw is brand new freshly assembled on a mobile base in my garage.
I'm on my second one....................http://home.wavecable.com/~m9er
G.I. told me that I was trying to get too much precision from a Contractor saw and that should just align it at 1.5 inches of blade height and toe out the fence to eliminate the burn
That might work for rip cuts, but what about cross cuts......
Edited 3/8/2006 9:02 pm ET by m9er
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