Hello,
I recently added a Freud 1/8″ blade to my almost brand new Delta TS350. The blade seems to be wobbling as it slows down. Actually, even though I haven’t had the time to check, I believe that it was also the cae with the stock blade (that one was a thinner kerf) but I had barely used it.
Anyway, I obviously need to spend more time testing this but here what happens: as the blade spins down (there is not brake on that table saw), as it goes slower, I start hearing what I can describe as a wobbling noise. It goes like chack…chack…chak…chak…chack…..chack…..chack…..chack……..chack………chack………chack….. (slower and slower).
I just made a (will have to be remade as I butchered it a bit) zero clearance insert for that blade from a scrap piece of cherry. The blade cut s kerf through it but looking at the kerf after the blade has stopped reveals something very weird (and I will try to take a photo of it when I can): the kerf appears straight and to have the right width, however, at the top left of the slot (when facing the saw) and the bottom right, there are 2 indentations made by the teeth of the blade that are slightly wider than the rest of the kerf and easily visible. Just at the top left and bottom right.
It seems that at full speed the blade is straight but it goes out of whack as it spins down.
What could be causing something like this (I do not have a very accurate way of measuring blade parallelism yet but did it with a starrett combination square and it seemed fine)?
Replies
Most likely you are seeing an optical illusion, it can look real weird under some florescent lights. The speed of the blade along with the pulsing of the light can make a strobe light effect. Blades do wobble, especially thin kerfs at full cut but not so that you could see it on the blade spinning. It does become obvious on the face of your cut. The extra cut in your insert could be from raising and lowering the blade as well as the abrasive action from the saw dust. If after making the insert, you raised the blade through it to make the slot, the blade will tick it a little. More so if the insert has side to side play. If the blade is 90° when you check it with a square, and you can't wiggle it, you probably don't have a problem.
Beat it to fit / Paint it to match
I have raised and lowered the blade through the insert only once after installing the insert, up to cut the kerf, down after I was done with the few cuts I needed to make. I do hear a much different sound when the blade is spinning down, that chack, chack chack, even though the kerf in the insert has been cut. While I would love to be satisfied with your answer, the extra cuts in the insert do not look normal to me and I don't think they come from lowering the blade. They are clean cuts, done while the blade was spinning (even if that was slower).I cannot see or hear a wobble at normal speed of operation and the cuts seem clean, although I haven't used it much yet.However, at a very slow speed, a wobble is really easy to see.
Edited 7/11/2006 3:02 pm ET by LeChuck
I went home for lunch and tried again. You might be right on the wobble. Pehaps it is a lighting effect. However I still hear the rubbing noise when the blade slows down or I spin it by hand. One thing that is sure though, is that I didn't make the insert very well and it looks like I introduced a slight cup in the middle while hand-planing it, and so it puts the blade at a very slight angle with the insert. I guess that explains why the space between the side of the kerf and the body of the blade is slighlty larger on the right side that on the left side (tilt of blade to insert is to the left). Not sure that explains the extra cuts made by the teeth at each end, but I guess I need to try again with a better insert first. If only they weren't so tricky to make for that TS...
You are probably seeing a harmonic wobble. As the blade slows down, it hits a certain speed where it will flutter quite dramatically for a fraction of a second because the vibration of the belt and pulleys matches the natural vibration frequency of the saw blade. As the blade slows down more, the vibration of the drive will no longer match the natural frequency of the blade and the flutter will stop. It is harmless and not worth worrying about since it won't occur when the blade is running at full speed.
The vibrating blade will hit the sides of the zero clearance insert and this is what is causing the blade tooth sized nicks at either end of the kerf in the plate.
The clacking sound is probably the sound of the starter switch in the motor engaging as the motor winds down. There will be one loud click as the switch engages followed by a series of smaller clicks as the engaged switch spins with the motor. This is also normal and harmless.
John White, Shop Manager, Fine Woodworking Magazine
john,Thank you for this explanation. It is quite convincing and reassuring. I don't need one more thing to worry about as I'm setting up the whole shop! It does look like things are fine at normal speed.The sound I hear is not from the motor, but simply the teeth of the blade rasping again the sides of the kerf as it slows down and making those extra cuts. The one thing I don't like with this is that it sounds like it makes it almost impossible to use a zero clearance insert. What I'm thinking is that after a number of starts and stops at various blade heights, the low speed wobble will end up enlarging the kerf enough that the zero clearance advantage will be gone...Although, one thing I can add is that just spinning the blade by hand (so at a relatively slow speed) is enough to make it wobble (and yet it is bolted on tight). I cannot see it by eye, but I definitely hear the teeth brush against the inside of the kerf (not all the teeth and just from time to time).
Edited 7/11/2006 5:51 pm ET by LeChuck
A few thousandths of an inch wobble is normal on a saw of this type, it is only a contractor's saw after all. You are worrying too much about the tool at this point, start cutting wood and building furniture-that's the whole point to having a shop. If you discover that you are having problems with the accuracy and quality of your saw cuts as you make furniture then start to look for the causes.
There are a dozen reasons why a saw won't cut well and it is almost always because the saw isn't tuned up properly or the blade is dull or the wrong type for the work being attempted, a wobble in the blade, unless it is extreme, is rarely the cause of poor cuts.
Don't take the concept of a zero clearance table insert too literally or too seriously. Unless you are crosscutting exceptionally splintery wood or thin veneers there is no real need for an airtight fit of the blade to the kerf in the insert. If you are in the situation where a very good fit is needed, then install an fresh uncut insert.
John
Thanks for the advice John.
You are welcome, I was hoping I didn't insult you or your saw.
Have fun with your new shop,
John
haha, no, and I'm sure I can speak for the saw as well :)I do know that the end result is what matters, but I am of the obsessive kind who like to go and find an explanation for everything. I always have an endless supply of questions and things that I need to figure out :)
My old Jet saw had a wobble like this. I replaced the V-belt with another V-belt, no big difference. Then I slapped a link belt on it. Major improvement! Much less vibration in general, I really love it.
(this will start a kerfluffle, guaranteed)forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
FG,
By kerfluffle do you mean a deluge of divergent dissertations diametrically disparate in dissimilarities descending upon the denizens of the debate?Regard it as just as desirable to build a chicken house as to build a cathedral. Frank Lloyd Wright
Yep, all of those d's and den some. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Is it an ATB style blade by any chance. These always look like they are going back and forth as they slow down.
Les
Yes, it's a Freud LU84R011 combination blade.
From the original couple of posts he made, it's not that it simply looks like it wobbles; it is scraping the zero-clearance throat insert also, so it is wobbling. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Well, yes ForestGirl, thanks for understanding that :)But John was probably right that I shouldn't worry about it unless I see some negative effects of it in the end result. Not in my character to not worry about it, but I'll try not to think about it too much :)
"...but I'll try not to think about it too much :)" Ahhhhhh, discipline of the mind. I like that. ;-)forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Well, there is definitely something wrong either with my blade or with the setup of the blade/tablesaw, or with the way I am using it (I am a beginner with this so that is a strong possibility).I just tried to rip a smallish piece of 3/4 plywood, about 20" long per 13" wide into 2 half strips. On the right side of the blade (the piece between the blade and fence), the cut is all burned on about 70% of the kerf lenght, as well as bowed. I have just trimmed the second strip to the same size, cutting off about 1/4" from it and what was a straight edge is now a clean but burned and bowed edge. When the edge is put on a straight surface, the bow is more than 1/32" high.So what could be the reason for that? A blade wobble? A misaligned blade? (I don't have a preceise way of doing that but it seems parallel to the miter slot and to the fence, or vice versa), or am I going too fast, too slow? Blade too high or too low? (for the first cut the teeth were about 1/8 higher than the wood, and I raised it higher for the second cut with no change).I edited this message to insist on one fact that I think is important: the cut is burned and bowed on the right side of the blade, but perfect on the left side with no burning and no bow.And a new edit: actually, the bow is matched by the shape on the other side of the kerf, it was just harder to see when put on the edge. The edges are complementary. However, as I said, the burn is only on one side.Thanks for any idea...Edited 7/15/2006 7:51 pm ET by LeChuck
Edited 7/15/2006 8:01 pm ET by LeChuck
What type blade (rip-CC-combo) and how many teeth? Is the blade dull? What type ply-wood and does it have any moisture content as some new? Did you force it through or let the saw dictate the feed? Did you maintain the same constant pressure with the stock against the fence? Was the kerf closing beyond the blade? Have you checked that the blade is 90* to the table? Have you checked that the fence is square to the blade?
An added thought, ripping is done with the grain. Cross-cutting across it of course. But... ply-wood has alternating grain. Are you ripping or cross-cutting? I have found a 60 tooth laminate blade works best for me with grains running both directions.
Just a few things that could cause burn. Ain't life simple! ha.. ha...
Good luck...
SARGE.. g-47
Edited 7/16/2006 1:01 am ET by SARGEgrinder47
It's Freud combination blade with 50 teeth that is brand new. The saw is brand new as well. The blade is at 90 degrees and the fence is parallel, or as much as I could measure with my combination squares. As for the rest, I'm not sure, and that's why I'm asking what type of issue could cause it to burn and bow that way. I can't tell if I forced it or not. I didn't seem to. I was also using the standard splitter and guard.It's not only the burn that is a problem, but the bow...and the fact that there was not burn on the other side of the blade.The plywood is something that seems to be already finished on one side, and has fairly thick plies. Given to me by someone else, and it's safe to say that it's been around for a while with no moisture issue (S.E. Arizona here....). It was actually about 5/8 thick. But once again, the left side of the cut was not burned. I guess I should try at the different feed rate, but it seemed all normal to me.
Another thing I noticed is that the bow shows up where the wood is burned. Meaning that for a few inches at the start of the cut and at the end of the cut, there is no bow and little burn. however the bow follows the burn on about 70-80% of the edge.
Try changing your feed rate to match how the saw responds to the stock. And if you have any more old ply-wood available that is not from the same source as what you are using, run it through with the same set-up after you get the bow with the current batch. That should tell you if you got some stock that has tension in it. If you have any real wood shorts, try one of them also with the same set-up.
I suspect it's just the ply-wood. But if you are getting the bow on all stock, you most likely have excessive run-out or a defective arbor or shaft and the problem lies within the saw, IMO. I would also lay the blade on a flat piece of glass to make sure you don't have a defective or warped blade. I realize it's new, but stuff happens.
In the im-mortal words of the the famous Pink Panther detective.. "I suspect no one.. an I suspect everyone". As in any trouble-shooting, you will have to eliminate one potential problem at a time starting with the most obvious to cause the problem.
Good luck...
SARGE.. g-47
Good advice, thanks. I will try to find some more stuff to cut today. I'm trying to make a router fence. I'll also take it out and check for flatness. If it's warped, I'm sure Sears will exchange it. Where did I put that receipt....
I wouldn't't over-look checking the flatness of the inner and outer blade washers and last but not least, check the over-all length of the fence to be sure it's not warped. You never know these days as those Tai's and Chinese just might be getting their straight edges on a "buy one get one free" from god only knows where.
Precision and quality of machining are not as much a priority in some portions of the globe as "get er done" cheap and the complaint department will attempt to take the zig out of the zag after the sale. It's there job to confuse you into thinking you're the only one that has ever had that problem. ha.. ha.. ha..ha..ha...
Good luck and always keep the lane clear when using it...
SARGE.. g-47
Edited 7/16/2006 12:00 pm ET by SARGEgrinder47
Oh I know about quality and quality control, or lack of it. Same thing with everything else from cameras, lenses, to TVs etc...etc...The TS350 seems like a good saw and certainly looked like the best deal in that range. I wish I could have bought a $1000 with more tune-up facility but that couldn't happen. On the other hand, I got to setup and use my DJ15 jointer yesterday night for the first time. What a nice, solid piece of machinery and relatively easy to setup...
I would not worry about having less than a $1000 table saw, LC. My saw cost $125 at a yard sale. I made a few improvements on my own. There is only a few jobs that I couldn't tackle and they involved lignum vitae, black walnut or locust 8/4 or over. Took those up the street to a neighbor who has a 5 HP Powermatic.
Your TS will cut 85% of what you can cut on a larger cabinet saw if the operator learns to stay within the capabilities of the saw and make a few improvements on your own. I personally don't feel you need a $60,000 Mercedes to get from point A to point B in a non-commercial setting. You can do that in a Chevy with less creature comforts an a canny ability to know how and what makes it tick.
If I have a chance, I might post a picture of my "Junk-Saw" latter. Right now, I gotta get ready to go racin' in my Chevy. :>)
Regards...
SARGE.. g-47
Edited 7/16/2006 12:41 pm ET by SARGEgrinder47
Here's a pic of my my second class ride. I affectionately call it "Junk Saw" as what it started as was picked up in a yard sale as junk and I touched it up here and made a change or two there. Like I said, it isn't a Mercedes but it's a good daily driver and it will dependably get ya there. :>)
Regards...
SARGE.. g-47
The fence and miter gauge look pretty good.
Well, the table saw is not my friend. I didn't get to do much woodworking for the past few weeks but got back into the workshop this weekend. I jointed, flattened, dimensioned, prepared a walnut board in order to make a box and then proceeded to rip it to width on the table saw. It was just 3/8" thick. And just like before, the TS burned it. I'm not sure what to do at this point since it burns every piece of wood I cut with it. I did get the blade out to check it a few weeks ago and it was flat. The TS had no problem cutting this piece, easy job, no resistance. I ran the piece along the fence prior to cutting with the TS off, to make sure that my beginning and end pencil makrs would end up exactly in the same spot along the blade.After the cut, almost the whole edge on the right side of the blade (the keeper side) is darkly burned, and each dark part has a bow to it that creates a gap, and I don't think ripping oversize then planing out the burns and bows by hand would be a good solution.Any ideas?The left side piece, the off-cut, has no burn at all, only on the right side piece. I kept the board straight and against the fence (T-square), I used a guard and splitter, and the board did not twist, really it was an easy cut. I guess I'm oing to try and hand-plane the edge flat now and hope I don't lose too much width.
Edited 8/13/2006 2:08 pm ET by LeChuck
Le,
Sounds like the trailing edge of the blade is closer to the fence than the leading edge. In other words the fence is not parallel to the blade.
Ripping with a blade more suited to crosscutting (not enough set in the teeth) will cause burning as well, due to excessive friction in the cut. Usually though,you'll see this on both sides of the cut to some degree.
Regards,
Ray Pine
That's the weirdest thing to me. The left side of the piece is absolutely clean. It is a bit crooked to match the right side, but it's not burned. If there was only a burn, it would be easy to clean with a few hand plane passes, but the biggest problem is the bow that it creates on the edge.
I too will vote for the blade and fence not being in parallel. In an ideal situation you want the fence to trail off just a bit to the right from front to back in relationship to the blade. By a little bit I'm talking thousandths of an inch. This keeps the work from the back edge of the blade.
I haven't read the other posts so I'm assuming you have the proper blade etc. in your saw for rip cuts.
Alright, just to keep people updated :)I did realign the fence very slight so there would be more space at the back using a 0.015 gauge. I still burned some wood during the rip but this time I went much faster than usual and the burning only happened when I had to slow down to reach for the push stick. There was not enough wood on the left side to keep pushing with that hand. So it appears that it is mostly a matter of technique and feeding speed. Just posting this for other beginners. It was apiece of butternut this time and it's very clear in the result that all burning stopped when feed speed was enough.I prefer to have to perfect my technique than worry about bad hardware :)Thanks for all th feedback.
Check your blade to see if it is parallel to the miter gage slots. It may have slipped out of alignment. Then check your fence to make sure it is aligned with the slots. Another thing that could cause this is using the wrong blade. Once as a beginner, I left a hollow ground plywood blade on the saw. I went into the shop to quickly rip a short piece of 3/4 inch poplar and really got into trouble. The blade heated, warped and burned the wood. To my surprise, when the blade cooled, it returned to its original flatness. The moral of this story : Never try to rip solid stock with a hollow ground plywood blade.
Thanks. The burn problem is solved. There's defintely something fishy with the alignment, even though all my measurements tell me that the blade is parallel to the miter slot. No, I don't have a dial to test nor the means to buy all kinds of testing equipment. Today I tried to cut some miters with the blade at 45 degrees, but the result is a miter that is only at 45 degrees at the end of the cut but not at the beginning (the length of the mitered surface changes). Right now I haven't figured out what type of misalignment in the blade can cause that. I guess probably that the blade is very slightly off in a counter-clockwise way but I wish this darn table saw had any precise and practical way of. It's the one piece of equipment in the shop that performs as cheaply as its price, everything else working very well. If only it provided a good way to fix those issues but it doesn't.rambling....rambling....rambling....
"...cut some miters with the blade at 45 degrees, but the result is a miter that is only at 45 degrees at the end of the cut but not at the beginning...." It is very, very common for a contractor saw to be out of alignment when the blade is tilted all the way to 45°. Something to do with the weight of the motor hanging on the works. Even saws that are set up and operating perfectly at 90° and cutting good at, say, 22° or whatever, can be "off" at 45°. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Forestgilr, thanks for your reply. So how the heck do you straighten a blade for 45 that won't be straight even if it's straight at 90 degrees...This is just plain irritating. It has taken me weeks to find the time to be in the workshop. I had tons of stuff to do on the cars each weekend and now I'm just trying to make a couple boxes for the kids, spent time choosing the right wood (a board of butternut, easy to work with), milling it, dimensioning it, even the resawing went without a hitch, the old planer did its job, routing gooves took a few minutes, sharpening card scrapers and scraping the board went fine, and then the darn table saw botches an easy task that should actually be the quickest part of the job. Got a couple extra inches left on the board but the next miters done to it better be perfect...I already have that nice Craftsman saw with the Biesemeyer fence and the easy trunnion adjustment on my wish list and since I don't have a rich uncle...maybe after a few months of savings...
Le,
Couple suggestions for you.
If you can make the miter cut by standing the stock on edge, and using the blade at 90* and presenting the stock to the blade at 45* it may be easier. You can use the crosscut guage set to 45*, or make a dedicated miter guage that is V shaped and has a strip to ride in one or both of the sawtable grooves. The advantage of this is that if the V is exactly 90* (a plywood factory corner for instance), you can still present it at a little off of 45* and by using both legs of the V to cut the mating miters, they will still add up to 90*, and will fit. Unless the corner you are wrapping the molding around isn't 90*...
Cutting miters or making crosscuts of any kind, on the table saw can be problematic because you are moving the stock across the table. This can introduce a tendency for the stock to creep in the cut unless you can clamp it to the guage, or hold the other end to a stop block. The movement will be so slight that you cannot feel it happening, but will show up as a burn from the trailing side of the blade, on either the miter or the offcut, and less than straight cut.
If the stock is too wide to stand on edge, then you have to tilt the blade. If it is not practical to adjust the blade to cut true, you may just have to make the cut a little bit long, and (gasp) adjust the fit with a (shudder) hand plane. I've heard there are people who can do this with some degree of repeatability. Just a little fun here, see my post in another thread about machine and hand technology, and how that relates to economy and scale. Sometimes it's easier to clean up in 5 minutes with a plane what it would take an hour to adjust on the saw, then you'd have to spend another hour to re-adjust the saw to 90* when you're through.
Good luck,
Ray Pine
Ray, thanks for your explanations. The first method would not be practical for this project since I am making a box with mitered corners and it's over 5 inches high. I do plan on making a crosscut sled one of these days. I had an aluminum one but I wasn't satisfied with it so I decided to sell it and make my own.I will probably setup the saw for 90 degrees again, leave it there, and find another solution for miters. Maybe I will do dovetails on this box instead, but the wood has a nice figure and a good 3-corner match would be great for that box.Cleaning up the miters with the block plane would be a good thing but for this project I'm afraid it would end up as sloppy work.David.
To adjust the blade alignment on a contractors saw, loosen the bolts that connect the trunions to the table. On my saw there are two for the front trunion and two for the back. Don't loosen them much . Just enough to shift the carriage until the blade lines up. Sometimes this takes two or three tries as it may shift as you tighten the bolts.
I'll try to adjust the trunnions when I have a couple hours to spend after I put it back to 90 degrees to make sure it's perfectly aligned. but based on my experience setting up the 90/45 stops on the same saw, I probably will make it worse than it was before. No matter how much tim I spent trying to set those hard-to reach spots, and no matter how hard I tightened, I could never get the stops to stay in the same place.
Do you know of any retired shop teachers close by? If you can find one, he may be glad to help. It helps to feel useful again to help someone in need.
Retired shop teacher.
Try 31260 under Jigs etc, that may identify the error.
It's a good tip, thanks.
Hello,I don't want to keep bringing this thread back to the top and force everyone to read it again, but I'm just posting an update to my sage with table saw alignment, and the latest problem: cutting 45 degree miters. I think I discovered today why my miters aren't straight. It seems that it would not be a problem with the table-saw after all, or less than I thought, but an issue that generates in the planer. I just acquaired a fractonal dial caliper, and this nifty tool told me that my boards don't have the same thickness on both edges when they come out of the planer. There is just a bit over 1/64th thickness difference. This is consistent over the whole length of the board. Now that doesn't sound like a huge diffence but it might be amplified and of course lead to the miters not being straight, since the miter surface will be "longer" on one end. So now I'm off to figure out how to make that planer cut straight....(I checked several boards that went throught the planer and the higher thickness is always on the same side, and since the boards are usually flipped end for end, it stays on the same side of the planer).
Sorry, the subject is Radial Arm saws but the fix is just as good for table saws.
Hey lechuck...some sawyers laugh in the face of absolute parallelism and insist that the fence be actually a tad wider at the back than the front.And cutting boards, no matter how thin, you are by the very act of cutting realeasing the inner tensions which exist WITHIN the board. Quite commonly Oak, ash, elm, cherry can close in around yer saw blade. Ie the kerf you cut with yer TS blade, just disappears at the end of the board. on a longer board, it sometimes releases so much inner tension that when you get to the end of the board, it just splits it for the last cuppla inches. And the release of tension can go either way, closing in the kerf or expanding it.Just cause you got a perfectly aligned sawing machine don't mean that the trees God made are gonna respect your concept of geometry.After all, that is why he invented hand planes.Eric
in Cowtown
Eric, please read the whole thread before answering. Ripping is not the problem, and the burning is gone. The problem is now a saw that can't properly (straight) crosscut a 5" wide piece of wood (especially when doing miters). It's not a problem of hand planes at this point. Before I took the board to the table saw it had been jointed, resawn, planed to thickness, and even hand-scraped, was the exact thickness all over. bottom line is the table saw can't handle what should have been a 5 minute operation, just cross-cutting the board into 5 pieces with a few miter cuts. And it's 7/16", no big deal.
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