I intend to purchase a pair of Freud rip blades to mount in tandem and cut tenons. Do I get the “full kerf” models to minimize deflection or do I get the “thin kerf” ones to reduce load on the saw?
My saw is a 1 1/2 HP Unisaw (1950 vintage). Because of the small motor, I’m leaning toward the “thin kerf”. Any advice/comments would be appreciated.
Regards,
Mack
“Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe”
Replies
Hello MackMAn using two blades in tantem can be quite dangerous. The offset form one blade can cause the other to wobble. Teeth may touch and shatter throwing metal into your face. Wear face protection.
He is talking of a spacer the same width as his tenon between the blades to leave the tenon after the cut, not two blades to make the groove.
What would you use as a spacer to hold the blades apart? If it is safe, I may try making some tenons using this set up in the coming months.
Edited 10/13/2008 11:28 pm ET by Tinkerer3
I use discs of mdf. ( one or another thickness) It has been many years since I cut them. I believe I drilled the arbor hole then mounted on my metal working lathe and turned the OD coaxial to the ID. Disc thickness is not tenon thickness because the carbides overhang the saw blade plate. Hope that makes sense. It will once you set it up.Thin kerf or not. Does not mater. I bought two identical model DeWalt Rip blades from Home Depot. The black ones with yellow lettering for what that is worth. Works great. Can use paper shims or the metal shim discs from a dado set to fine tune tenon width.Put the rail or what ever to be tenoned in a substantial tenoning jig with a positive stop the rail can seat against along a section of its length and a stout hold down so there is no way the blades can grab the work.In other words don't hold the work on the jig with your hands; clamp it on.When you cut your zero clearance throat plate be sure it is well held down before you raise the blades up into it to cut the slots.
Edited 10/14/2008 12:12 am by roc
Baltic Birch plywood will work. If you were going to make them often you could have some machined from steel, aluminum, or a reinforced plastic like Micarta.
It is dangerous none the less. he is a silly silly man. I pray for his safety and wish him no ill will.
"--he's a silly, silly man--"
Thanks for your prayers but please use them for our troops, fire fighters, police and others in harms way. The method I have seen MANY TIMES in magazines, books and even a video or two features a wooden back up to the tenon so that there is absolutely NO CHANCE of the piece of wood coming back at me.
In order for the piece of wood to break off in the first place it would have to be very unsound which I would not use as a structural piece to begin with. The tenons would never be less than 1/4" thick and being only an inch or so long would be plenty strong to stand the strain. I had a set of spacers made years ago with this in mind; they're machined steel. I have a set of shims from my dado set to fine tune.
I really don't see what makes this so silly in your estimation. The only thing about it that I find silly is me taking the time to respond to a person who obviously (to me anyway) has a very narrow concept of methods of work AND when calling me "a silly, silly man" could not even have the courtesy to do it directly. But do, in any case, have a very fine evening. I mean you no ill will either!
Regards,
Mack
"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
Edited 10/14/2008 10:31 pm ET by Mackwood
I find it hilarious that a person who begs favors of imaginary friends, fairies etc. finds you silly. Perhaps he can offer up a virgin or at the very least a bit of roasted flesh.
Your method seems eminently safe and practical to me. I use a stacked cutter on my shaper to do tenons if I have a lot to do. If I did not have a shaper I would use the same method you are.
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Men will never be free until the last king is strangled with the entrails of the last priest.~ Denis Diderot
Mack,
Seems to me that either there is an excess of paranoia or friend Sandman has got the wrong end of the stick.But if paranoia persists then I would suggest that if spacers are made in anything other than a metal of some sort then plywood is a reliable choice. In any event I would not be afraid of a disc clamped between two saw blades just up and bursting- just doesn't happen.
But someone said that there was a rim speed in hundreds of mph....Let us look at a (big) spacer of diameter, say, 8 inches and assume an arbor speed of 3000 rpm.My calculation of the peripheral speed of this disc is 71.4 miles per hour . Not too frightening by any means, but if paranoia still persists then it can be further stoked by the the thought of carbide teeth flying around....(;)
I mentioned previously that I am not keen on this method of cutting tenons but exploding spacer discs is not one of my reasons for this sentiment.Philip Marcou
but you would probably use more like three inch diameter to make room for the tenon instead of eight inches which would result in about twenty six and a half mph. I ride my bicycle faster than that.
Edited 10/18/2008 11:38 pm ET by Tinkerer3
That is correct, and that is why I used a (big) example of 8 inches, knowing that a typical wooden spacer would have a diameter of around 4 inches.Philip Marcou
Nah this isn't silly.In fact the first place I learned about it was in a book by Bob Moran called The Right Technique ISBN 0-7621-0228-4 published by American Woodworker/Reader's Digest. Thats got to make it alright doesn't it ? : )He shows at least three ways to do any one operation. He shows in this book a decent tenoning jig. I made it and use it. Does not allow for angled tenons but could modify the design.In fact I just noticed; he lists a blade spacer kit from Delta for doing this: part #34-171
Honorable sandman 605 ,
Somehow I get the feeling we may already know you , perhaps ?
You have made it clear you don't agree with the method the OP was asking about , I too would not and do not use the two blades to create tenons . Well how would you suggest the OP does it ?
regards dusty
Mr Dusty thank you for your kind words. It's very simple you see. The original poster cuts one half of the tenon on the table saw, then flips the piece around to cut the other half. Done.
I find it very strange that people who are so hell bent at standing on the podium and shouting the word "craftsmanship" are the same people who look for ways to skip corners and/or increase productivity by trying unproven and dangerous methods. How much time will this "trick" really save? By the time this poster figures out the jigs necessary for his little trick to work, he would be half way done cutting all of his tenons. If time is of the essence for this man, then I gather a CNC machine should be purchased so that productivity of his "hand crafted" furniture can be maximized. I also suggest he should call his furniture "Amish Made" so that city folk get a warm fuzzy feeling when they look at his work.
Edited 10/19/2008 10:52 am ET by sandman605
Edited 10/19/2008 10:54 am ET by sandman605
My, that was a nasty little missive. Mackwood has been posting here since 2003, perhaps you could read back through some of his posts and tell us where he has been at the podium shouting about anything.
Not everyone here is a Luddite, mankind has a long history of innovation and improvement in the quest for accuracy and efficiency. The horseless carriage was decried as impractical and dangerous at one point. Perhaps that is why you are up on your high horse.
Not all fine furniture is handcrafted but I take it you spend your life cutting all of your joints with hand tools. I would suggest that by your reasoning those hand tools are dangerous and that you are "skipping corners" by using them. You should be gnawing down the tree, surfacing the wood with your fingernails and lashing your joints with vines.
Pretty ballsy suggesting that the OP lie about the provenance of his work. A reflection of your character perhaps?
You obviously did not spend much of your six days on the forum reading.
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Men will never be free until the last king is strangled with the entrails of the last priest.~ Denis Diderot
Hi d ,
I think we know sandman , perhaps by another screen name , his style is so familiar . He almost stuck his chin out there and challenged all to take a swing at him . Maybe I'm mistaken but I got a feeling he has been here and done this before .
dusty
" knowledge without experience is simply information "
Mark twain
Hi Dusty,
I could be wrong but I don't get the feeling he's one of our regular curmudgeons. Philip is right, sandfleas posts are devoid of content and logic.
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Men will never be free until the last king is strangled with the entrails of the last priest.~ Denis Diderot
sandman"The original poster cuts one half of the tenon on the table saw, then flips the piece around to cut the other half. Done"Actually, no. That is NOT the craftsman-like way to do it.One cuts one cheek of the tenon on the table saw, then moves the tenon jig an appropriate distance for the blade to cut the other cheek, all the while keeping the same reference side of the piece against the jig so that accuracy is maintained. Otherwise, all that can be accomplished is a tenon centered on the piece referenced from two different faces with thickness of the tenon itself a guessing-game.But you knew that, didn't you. You were just too angry to get it out right, as evidenced by your need to edit your attack several times. Anger can do that. And arrogance.But if the OP's method is a "trick,' I guess I should be taken out and flogged for the technical overkill I use for this sort of thing. Heaven's, I use a horizontal slot mortiser and an end mill. All I have to do, after the machine is set up is move a long handle around and the several-thousand dollar machine and all the engineering that went into it (in Europe, that place where fine craftsmanship is unknown) "automatically" produces the (perfectly-formed) tenon.And I guess that my use of a stack of 3 FTG circular saw blades with spacers in my shaper to simultaneously cut spline slots in the corners of picture frames is WAY too much for you to tolerate. After all, what ever happened to hand cutting the slots, one at a time as I first did to develop the technique. Hell, if it was good enough for grandpop, what business do any of us have improving the technology?I suppose that you approve all the "research and development" that went into the design of table saws and circular blades UP UNTIL YOU BECAME AWARE OF THE TECHNOLOGY. But NOTHING beyond that point. The technology police have spoken!No one else is allowed to continue the left-brain process and further develop and refine. Any who do are subject to ridicule and accusations of lack of craftsmanship. All development must come to a stop at your level of understanding.Remarkable.Rich
Now I understand why this forum has the reputation it does. It is nothing more than a bunch of grumpy old men with sawdust stuffed in their panties. I am NOT going to argue over the proper way to cut tenons as it would be like signing Opera to a deaf mute. However, I will leave you with this; Any craftsman that compromises safety over productivity is silly, plain silly.
You gentlemen can battle between yourselves over the quickest way to cut tenons Speedy Gonzales fast. Just don't come crawling to me for forgiveness when your table saw insert smashes into your fluffy beards like a shotgun blast. I wish you no ill will.
Let me get this straight.... you are saying that using Rich's horizontal mortiser to make tenons will somehow cause his tablesaw insert to fly up and hit him? Using dual blades on the tablesaw with a workpiece clamped in a tenoning jig will magically suck up the insert and fling it past the jig and the workpiece? The shaper with dual cutters that I use for multiple tenons will cause the table saw insert to hit me?
You can't make a good argument for your position because the facts and physics don't support you. You sir are a nut.
From your first post on this thread it was obvious that either you did not read or did not comprehend what the OP was proposing.
I am not surprised that you came from a forum where thinking is not allowed and there is only THE ONE TRUE WAY and all other thoughts are heresy.
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Men will never be free until the last king is strangled with the entrails of the last priest.~ Denis Diderot
No Dr Green, my response was to the original poster who wanted to use two blades at once in his table saw which I do not recommend merely for safety. I only responded to Rich because he was mean and nasty to me. However, you are much nastier and I demand you go to the privy and wash out your filthy potty mouth with soap!!! Rinse and repeat until you clean you soul you hateful man.
I was told about this forum merely through other forums which I will not divulge. Many posters at the other forums feel that the GOMw/SITP (grumpy old men with sawdust in their panties) are pre-Madonnas that criticizes and belittle other posters who don't share their same viewpoints. Now I see what they were talking about as seeing IS believing.
I HAVE scrolled through the various posting, especially the ones that bad mouth this very magazine with sheer awe and contempt!!! How pathetic is is to be a GOMw/SITP and complain about the content of Fine Woodworking all the while using this free service for your own self proclamation and profit. Sounds to me to be quite HYPOCRITICAL. Somehow I have the feeling some of you posters actually work for competitor publications. Who are You? Show your ugly face or fluffy beard!
My ugly mug and fluffy beard are there for all to see by merely clicking on my name at the top of the post. Where is yours?
You seem to have a bit of beard envy or perhaps fetish, are your huevos not producing enough testosterone to grow your own? Is this also the reason for your predilection for wearing panties? Are you engaging in what used to be called "self abuse" while thinking about beards, panties and sawdust?
Are you going to explain what is so inherently unsafe about running two blades spaced apart on an arbor in the tablesaw?
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Men will never be free until the last king is strangled with the entrails of the last priest.~ Denis Diderot
Dear Sandy,
"(grumpy old men with sawdust in their panties) are pre-Madonnas that criticizes and belittle other posters who don't share their same viewpoints. "
What is a "pre-Madonna"?
Someone who has not yet seen the "Like a Virgin" video?
Someone antithetical to a "post-Raphaelite"?
Carry on. A difference of opinion that degrades into criticising and belittling is high entertainment for some of us. Knickers in a twist, sawdust-laden or not, loads of fun.
Welcome to the forum, I think you'll fit right in, really.
grumpy old Ray
And now you leave no doubt whatsoever about your pedantic and silly position with an ad hominem attack against, not just one person, but, wow, the entire forum membership! I was wondering when you would throw your little tantrum. Funny how often this happens when someone with nothing really to contribute gets confronted about rigid and nonsensical assertions.The PROPER WAY to cut tenons. Proper way? Man, you sure do like listening to your own opinions!"Just don't come crawling to me for forgiveness"Not to worry.
he is a legend in his own mind
Hi sandman605,
It's me again; Mack. I suggest that you seek another forum; one where the posters are all as enlightened and advanced as yourself. There is surely no point in someone with your skills and intelligence hanging around with all of us idiots!!
We'll just keep wallowing and muddling along in our misery and you can feel very good about yourself in that you at least tried to straighten us out.
Mack"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
Why, Charles, where've you been? Not that we missed you, just wondering who else's arse you've had your head stuck up. You know, sooner or later you're going to run out of your predictably inventive usernames. I've got a few in mind, should you so require.
I don't think that is Charles.There is just no content to that blather, either.No, definitely not Oilstone.....Philip Marcou
Well, then, if it is not Charles, I apologize. Nonetheless, the tone seems awfully familiar
Hi pzaxtl ,
I think you are more right then wrong .
dusty
I had that same feeling at a couple of points during this thread. I guess we'll never know for sure.
Regards,
Mack"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
I've noticed a few grumpy old men on this forum over the years and now we can add another to the list.
sandman , Just for clarification , could you give example of these tricks and dangerous and un proven methods that some of us may want to use .
When you say un proven do you mean never been tried or perfected yet , as in brand new ?
dusty
Hi there Sandman 605,
You have a nasty habit of saying negative things about people but not "to their face". I would suggest that you go back to my original post and read it---slowly. There was no claim of anything what-so-ever; only a simple (so I thought at the time) question.
If you want to accuse me of things or argue with me why don't you address me. I don't claim to be any sort of craftsman; I don't make things to sell; MY GOD I DON'T EVEN HAVE A WEBSITE!!! I just do what I do for my own enjoyment. If that bothers you, so be it, but don't make up a story about what I am or what I do and tell it to someone else. You have absolutely no bloody clue about me so if you want to make stuff up, use yourself as the cast of characters!!
I still harbor no ill will towards you but man it is getting pretty tempting!! LOL
Regards,
Mack"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
I am a retired carpenter and cabinet maker. I have used the two sawblade approach with a shopbuilt tenon jig since 1961. In most shops this was standard practice .I do not recall ever seeing or hearing of an accident or other mishaps using this method.
Regardless of stock width,the tenon is exactly the width you want. Any slight variance in the stock thickness will make the tenon thicker than you want with your method. I have on occasion made one cut ,reversed the stock and made the second cut.I do this when I only have one or two tenons to cut and it is not worth the effort to install two blades and a spacer.
Stock width can vary in thickness,even if planed on the same machine at the same time. Slight changes because of blade wear,wood density, very slight differences from table to cutters,etc can contribute to stock thickness differences. That's why cabinet scrapers and sandpaper were invented.
I checked your profile to see if you are in the trades, no information given. I imagine from your last post that you are an elitist, and your 23 posts are probably the most important posts ever written on this forum.Get a life pal, there are many ways to accomplish a job.Whether one blade and tenon jig,two blades ,or marking gauge and backsaw,they all work, and none are dangerous with a bit of care.
I'm looking forward to your 24th post.
mike
Mike,
Thanks for your clear description of the double blade and tenon jig approach, from the view of a tradesman. Dang, I still can't see how it can be any more dangerous than most any other wood machining procedure, neither can I wait to see how Sandman does it safely-if at all.
Here's another dangerous and unsafe method, which I have been using for a number of years. I have a heavy radial arm saw which I use to cut and define shoulder length, then I complete the tenon on that sliding table shaper with that heavy plate saw. I prefer a single saw blade as the tenon will always be central, and I do get my thicknesser to machine to close tolerance: I am the only operator so that sort of problem is basically non-existent.I also feel that it is easier to centralise a tenon by single blade and flip method because you can sneak up on it using a test piece-whereas with the double blade method you only get one chance-and still suffer from a problem if thickness machining has been inconsistent. This approach allows me to make any slight adjustment to tenon thickness easily and quickly as the shaper has a fine height adjustment. I have found that different wood species give different results when trying to cut tenons with blades separated by a spacer. The other reason for my preference is that I prefer to cut mortises first, then cut tenons to fit, since tenons are simpler to adjust than mortises, and I cut all mortises with a hollow square mortiser.
Undoubtedly it is a question of plus and minus for both methods, influenced by equipment available , but far preferable to cutting them by hand. One must admit that the novelty of hand cutting tenons soon wears off when there are even a few to make, since even a simple frame will have a minimum of four tenons to do.Philip Marcou
Phillip, your method of cutting tenons is very good. Your reasoning makes sense, especially if your shop is not a production shop. I agree that different species cut with a double blade and spacer sometimes gives me results that require a bit more work. I have found that the harder the stock, the truer the tenon.
Now that I'm retired, I'll cut a few tenons by hand, just to make sure I still can.
mike
"trying unproven...methods"All tried-and-true techniques were once unproven methods. Imagine if we were trying to work wood with a sharp rock...Chris @ http://www.flairwoodwork.spaces.live.com
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
I've done that with a somewhat newer 1 1/2 hp Unisaw, and full-kerf blades. You're probably cutting tenons which are only an inch long or less (otherwise your mortise gets troublesome), so the blades aren't cutting very deep, and don't require giant horsepower. If you've run a dado head on your saw at that depth, it was removing move material than the two saw blades will.
I found it a good thing to make a zero-clearance insert for the saw, with two slots in it for the two blades.
I am not pro that concept so prefer not to comment other than to ask that you keep us informed on progress and results.
Mack:
Here's what I do -- a lot -- and it works well.
I have a Freud stacked dado set. I use the two outer blades from the set to cut tennons. My saw is only 1.5 hp as well (fn1), and this is not a problem. Tennons are usually pretty small, short cuts, and the saw never breaks a sweat cutting 'em.
I made spacers from various materials to give me different thicknesses. MDF pywood for 1/2", tempered masonite for 1/4", and sheet metal for thinner shims. I made the spacers on a drill press by clamping the stock to the table, drilling for the arbor hole, and then using a hole saw to cut the circumference. Keeping the stock clamped until both the center hole and circumference are cut keeps everything concentric. My spacers are 3" in diameter.
For wide tennons, like 3/4", my saw arbor is not long enough to allow me to use the outer washer between the nut and blade. This has not been a problem. FWIW, I've never had any problem with blade wobble, either in normal operations (for which I usually use thin kerf blades) or dadoing. The *only* time I get anything like this is if the blade overheats and deforms due to trying to cut a piece of wood that has internal stress causing it to pinch the blade. This never happens when cutting tennons, since the offcuts are so small they can't really pinch the blade with any force at all.
I store the spacers on a dowel fastened to a wooden block on which I have posted a table of what spacer/shim combinations are used make tenons exactly sized for my mortise chisels and typical dado setups. The initial tweaking to get the perfect combinations is a bit of a hassel, but once you've done it, and made note of it for future reference, setup is really quick -- just like setting up for a dado. Note that, to get, e.g., a 1/2" tennon, you can't just use a 1/2" spacer -- the set of the blade mandates using a spacer somewhat larger than 1/2", since the cut is a bit wider than the thickness of the saw plate near the arbor. This means that your spacer setups are only accurate for one particular set of blades.
I have the 8" dado set, and I've never had a problem using it on this saw, up to the full depth of cut. I use a removable insert throat plate, and usually just use the plate that I've set up for dados that's closest to the outside width of the blade setup. Keep both hands on the jig handles at all times, and push slowly and smoothly through the cut.
I cut the cheeks first on the TS using a dado jig, and then cut the shoulders at the RAS using a stop. Or, when I'm luck enough to have My Lovely Assistant with me in the shop, one of us will run the cheeks, the other will cut the shoulders. It's really very quick.
Using this method, it's more trouble than it's worth to worry about getting the tennon exactly centered. You can usually eyeball it to within a few thou', but I never worry about it much more than eyball. I carefully mark the face/fence side of each piece, and use that as a reference when cutting corresponding mortises. I generally make sure to reference all my cuts from the face side -- less chance for misalignment of mating surfaces due to centering errors or minor differences in stock thicknesses.
I have found this an efficient and safe operation. The only time when I've ever had any issues (and it's minor) is on the rare occasion when I need to cut the shoulders first. Then, the cheek waste tends to get kicked out by the blade. No biggie, 'cause they are small and light, and don't really kick out all that hard, but you want to be aware of it and take an appropriate position while sawing.
Large, or especially deep, tennons I cut with a router setup (if not cut by hand) using a tennon fence made for each project. But that's a different story.
Mike Hennessy
Pittsburgh, PA
fn1. I actually like the fact that my saw is what many would consider "underpowered". Sure, I need to take a slow cut if I'm cutting, say 2" white oak. But I don't do that all that often and 1" stuff is no problem at all. On the plus side, I find that this saw tends to simply stall if, for example, a cut closes and pinches the blade. Personally, I prefer a stalled saw to a nasty kickback.
Mike,
I know what you mean about the "supposedly" underpowered saw. My first real TS was a 1946 vintage Delta TILTING TABLE saw. It's got two belts on the side (originally had only one) that are almost 4' in length. The motor was only rated at 3/4 hp when new but it's about the size of a round waste basket. The thing cuts very nicely on smaller pieces but runs into problems handling sheet stock, especially with the table tilted.
Point is; it cuts great but when something hangs up or pinches, the belts slip. I've never had a serious kickback with it and I have to believe I've given it a few opportunities!
When I got the "new" saw (1950 Unisaw), I was actually quite paranoid for a while. I made lots of gadgets to hold stuff against the fence, bought a "Merlin" splitter and was EXTREMELY CAUTIOUS for quite a while. I still use all the gadgets and the splitter for ripping but I now realize that this saw is only slightly more prone to kickback than my old one.
I'm never in a hurry so I can't imagine "upgrading" to a 3 hp or even 5 hp motor. If I need to cut very thick or dense wood, I use a blade with less teeth and just slow down a bit.
Regards,
Mack "Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
"fn1. I actually like the fact that my saw is what many would consider "underpowered". Sure, I need to take a slow cut if I'm cutting, say 2" white oak. But I don't do that all that often and 1" stuff is no problem at all. On the plus side, I find that this saw tends to simply stall if, for example, a cut closes and pinches the blade."
Just as an aside: Horse power numbers jumped when TCT blades took over from the ordinary hss and normal steels plates, because more power is required to make them cut efficiently. If you ever see any new non tipped blades of good quality or get hold of properly doctored ones try them and you will see how easily they cut - 11/2 horse is plenty then.
There is a strong argument for the notion that more power decreases chances of kick back, which is the opposite to what some folk may believe: there is less chance of the saw digging into the work and throwing it back. But I wouldn't argue with a saw anyway.Philip Marcou
Mike,Dado blades are designed to cut a cleaner shoulder on the side marked "out". Do you reverse the position of the blades so that the "out" faces "in" to get clean cheeks? Tenon cheeks, to be precise.Chris @ http://www.flairwoodwork.spaces.live.com
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
"Do you reverse the position of the blades?"
Nope. The cheeks are plenty clean with the blades set up as for a dado. Certainly cleaner than when I do 'em the ol' fashioned way, using sweat instead of electricity. ;-)
Frankly, I've never noticed the difference in the cut quality on one side vs. the other. I think it's more that the teeth are set overlapping more of the inside face of the blade than the outside, so they overlap the chippers better -- not that the teeth are less sharp, or whatever, on one side. I mean, non-symetrical sharpening would be more trouble than it was worth for the guy doing the sharpening -- he'd have to do a seperate setup to do a "worse" job on one edge of the blade. Can't see that happening.
Mike HennessyPittsburgh, PA
Edit: Thinking on it further, but without a set of blades in front of me to confirm it, it may be that the teeth of a dado blade are beveled in only one direction, as opposed to ATB. Still, I've never worried about it, so long as the pointy parts are facing front. ;-)
Hey, this is the inside of a joint. It ain't supposed to be all purty. Frankly, a little additional roughness may actually help the glue do it's job. But that said, I've never noticed the difference, but I don't see any harm or danger in setting them up the other way if you want -- whatever floats yer boat!
Edited 10/17/2008 7:05 am ET by MikeHennessy
Mike , Hey wait , couldn't that be several thou off , LOL !
dusty, many thousands off each day of woodworking add up to close to an 1/8" at the end of the month
Mack,
Why not just use a tenoning jig and one blade to cut the tenons? Cut some scrap wood to the same thickness as the project wood and use it to fine tune the adjustments on the tenoning jig to give you a perfect fit. It shouldn't take any longer to set this up than a two blade system with spacers and it just seems safer to me.
Jim
IMHO. I would not use anything that wasn't meant to be but on a saw arbor, period. Use blade stiffners, arbor washers, metal shims or similar items. MDF, masonite or plywood are accidents waiting to happen. The rim speed is going to be in the hundreds of MPH, too fast for me to trust anything but metal. If you think a kick back is scarry, wait till a chunk of wood comes flying out from between those blades.
But realistically, I would use my tennoning jig as mentioned in another post.
Work Safe, Count to 10 when your done for the day !!
Bruce S.
Edited 10/14/2008 8:03 pm ET by BruceS
Edited 10/14/2008 8:04 pm ET by BruceS
Bruce,I also have used an MDF spacer between two blades to cut tenons. The MDF is a donut only 3" in diameter, firmly clamped between the two blades. The rim speed on a 10" tablesaw blade is about 140 mph. The rim speed of the 3" donut is only 30% of that, or 42 mph.
MDF is plenty strong for the job. Look at that soft magnetic dado washer stuff that is sold. It is weak, but it works just fine.I like the idea of using 8" blades (dado cutters) instead of 10". It is much safer when making your ZC insert cuts, and less prone to wander off line in the cut. On my dado set, the outer blades are asymmetrical for a reason, which is to give smooth sides to the dado groove. For cutting tenons, you might want to put the left blade on the right side and vice versa, so that the clean cut surface is on the tenon, rather than on the waste.Bill
Is this for production? Will all tenons be same size or will you use different spacers between the blades? I'm wondering how many tenons you are cutting that would justify this set-up.
Greg
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Exo 35:30-35
Cincinnati
I certainly would not use this set up for a handful of tenons. I've been doing them (a different way) for many years but have recently started a trend of doing small groups of what ever I'm making; usually 8-12 pieces. If this trend continues I will end up, sooner or later, making something with several to many tenons on each piece. If and when this happens, I want to have two identical blades to experiment with and try this method.
As I've posted, I've known about this method for ---a long time and even had a set of spaces made up when I had access to a machine shop some 20 odd years ago. They are 1/4", 3/8" and 1/2" and are made of steel. Should be absolutely no problem what-so-ever to add a couple of shims from my dado set to fine tune this set up.
I don't know for absolute certain that I will ever get to it but this thread certainly has given me a bit of extra motivation if you know what I mean! HAHAHAHA
Regards,
Mack
"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
MAc,I think I have seen this setup in high production shops. There is a little more danger running tandem blades in that they have to be in parallel or you run a greater risk of kickback. I hope my post did not come across as critical to you. I was just wondering if you were trying to increase efficiency and decrease labor costs. I have access to milling machine and lathe and have ideas myself for tools and jigs to help me accomplish my projects. I do extend the best of my hope that this works well for you. When it does, post a few photos for us.RegardsGreg
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I didn't take it as critical at all. I can see where parallelism of the blades would be important. I do have a nice set of machined steel spacers which should do the trick. If and when I ever get around to actually setting up and using this method, I'll be sure to get pictures.
Regards,
Mack
"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
Either,full kerf or thin kerf. Makes no difference for cutting tenons. You still have plenty of hp.I use 5/8 dia washers for spacers and paper if needed.As far as this method being dangerous, all I can say is I used this method for about 46 years without mishap.I generally use a homemade tenon jig and two identical blades.
mike
Ditto. Methinks those who claim this is dangerous know not of what they speak. It's no more dangerous than using a tenon jig with a single blade. And it's actually easier to set up than making two cuts with one blade, since there's less tweaking to get the tennon just the right thickness.
Mike HennessyPittsburgh, PA
Why not use the Freud box joint set of blades? The blades have carbide sticking out on only one side and you stack the two blades together making sure the carbide tips don't touch.
http://www.amazon.com/Freud-SBOX8-Cutter-4-Inch-grooves/dp/B000ASGV1E/ref=sr_1_1?ie=UTF8&s=hi&qid=1224127729&sr=8-1
I'm not sure, but it sounds like these pair of blade would work for what you are talking about or am I missing something?
Thanks for the info. I will look into that set as they may "kill two birds with one stone" (please don't tell OSHA or SPCA). LOL
Regards,
Mack"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
Mack,
If you go this route, make sure you don't get a TCG (triple chip grind) rip blade. I have one, love it - it does wonderfully clean rips and quite acceptable crosscuts - but leaves some waste in the corner of non-through cuts which has to be cleaned up later. Flat-top is what you want. I'd go full kerf too.
Chris @ www.flairwoodwork.spaces.live.com
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
Actually, my take on this is that it doesn't really matter what kind of blades you use as long as they're matching in diameter. If you use the cheek cuts to take away the tops of the shoulder cuts, then what is left after the shoulders are cut is of no consequence.
Also, for those who are uncertain about the safety of the setup, this cutting sequence would allow you to extend the dual blades the minimal height - Not a major reduction in height, but it might some feel a little more secure...
Zolton
If you see a possum running around in here, kill it. It's not a pet. - Jackie Moon
Hi Mack,
I've read all the posts so far in this discussion and I have just one question: Why not use either the Freud box cutter(s) or a dado set?
The box cutters will cut either a ¼" or 3/8" wide trench/rabbet and a good dado set usually allows multiple widths.
I have both the Freud box cutters and their adjustable stacked dado set and have not needed/wanted anything else, yet.
Regards,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
I've also read all the posts (don't ask me why) and have lots of questions!!! LOL
I have a Freud stack dado set and could very well use the two "outside" cutters to do the dreaded deed! There would be plenty depth of cut even though it's an 8" set. If I ever actually get around to trying it, I'll probably do just that.
I've seen the box joint set in the ads but don't have one; if I get into a "box joint phase" I will have to invest in one.
Regards,
Mack"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
Now that the thread has diverged:
I would use a pair of full kerf blades. Personally I use the outside blades from a dado set.
For spacers I have a hand full of 5/8-inch hardened washers. They are pretty close to an 1/8-inch thick, (the ones I have mic out to 0.120). I have two sets of Veritas shims, that I use to fine tune the width between the blades, and tennon.
Do not get plain old washers, be sure they are grade 8 or higher. The regular grade 5, and lower grade common washers are stamped and the faces may not be parallel. The grade 8 and higher have parallel faces, so that you don't misload the higher strength, but more brittle bolts. The grade 8 washers are available from old fashioned hardware stores, dedicated fastener suppliers, and auto parts stores.
Ok this thread may have been beat to death but I just came across this while looking for something else if you are interested:
http://www.taunton.com/finewoodworking/SkillsAndTechniques/SkillsAndTechniquesPDF.aspx?id=2260
Note to person that posted question about big bandsaw using very narrow blade; See Macs bandsaw in this article.
roc,
You beat me to it. I was just sorting thru my magazines tonite. SWMBO told me I have to throw some away, I said fine but all of the Fine Woodworking and Fine Home Building mags stay. Anyway, the article that you linked to is on the cover of issue 95, I believe.
Had a good chuckle when I saw the picture on the cover of the author cutting tenons with...gasp!... two blades. I remember reading in following issues complaints from some of the readers saying the method was unsafe. I think that the main complaint was the jig he used and how close his fingers are to the blades though, not the double blades themselves. If you look close at the picture in your link it looks like he is missing his pinkie finger, he isn't but it looks like it. The guy is obviously a menace to society. :^)
Rob
> Yep # 95Hey about anything Mac Campbell does is worth investigating in my book. He knows his stuff. I have not read anything by him in a while; I hope he is doing well.>Complaints/jig
Hey that must be where I picked up the warning to clamp the work to the jig and not try to hold it by hand.Man it is nice to get out the old "over size" issues. The articles are really great !Tell your wife the magazines are ballast so the house doesn't blow away in a high wind. If she doesn't buy that I hear they work almost as well at keeping the garage from blowing away.We got fifty mile per hour winds here tonight and I got almost a full set of FWW so maybe we will make it.
Edited 10/22/2008 2:14 am by roc
roc,
Thanks! I even have that issue! I will definitely look it up when I get home.
Mack"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
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