I’m having an issue I can’t seem to figure out. When cutting 1/2″ or 3/4″ thk. plywood panels on my TS the cut pieces are narrower in the middle of the board, creating a “hollow” for lack of a better term. Now, I do notice as I’m cutting the panel wants to pull away from the fence and it seems like I am applying pressure to keep the panel against the fence. Last night I cut both 1/2″ and 1/4″ and the 1/4″ cut perfect. Am I not applying enough pressure to keep it on the fence. I’m afraid to push any harder for fear of moving the fence. When I rip solid wood and use a feather board the cuts are fine as well. But I use a Frued rip blade then.
My fence is parallel with the blade. The blade is a $40 Freud combination blade. Seems sharp. Would a better blade make and difference?? Is there somethign I’m overlooking?
I say I fear the fence moving because that has happened twice. The saw is a Bridgewood 3hp cabinet saw. It happened this past weekend when I was using my router table I have in the extension table area of the saw. I had my router fence clamped to the TS fence and it moved while running boards along the router fence. Anything I can do to make the fence clamp better. I did run a little sandpaper over the cam that clamps against the rail.
Replies
I had a similar problem with my old craftsmen table saw, material pulling away from the fence. In my case the spliter was not aligned perfectly with the blade and causing this problem.
Robert
If your saw has a Biesemeyer type fence you can tighten the clamps grip on the rail by turning both of the adjusting screws in slightly, you'll have to check the fence to blade alignment after you've moved the screws. Make sure the blade to fence alignment is dead on parallel and is still good when the fence is moved farther out on the rails.
Having to apply excess feed pressure because of a dull blade or drag on the table top can also create control problems. Using a sharp blade and waxing the table top can improve control of sheet goods. Adequate infeed and outfeed support of the sheet is also required for accurate cuts.
If you are starting out cutting full sheets of plywood, they can be very hard to control and keep tight against the fence. The best technique is to cut down the sheet to slightly oversize pieces and then recut the easier to handle smaller pieces to final size, I always do this.
John W.
Edited 10/5/2005 1:10 pm ET by JohnWW
The fence should not be "dead on" parallel to the blade. In fact, the fence should be a few thousandths of an inch further away from the blade's trailing edge than from its leading edge (measured when you fully raise the blade). Using a splitter is a real help, but like someone here said, it should be aligned with the blade, and somewhat smaller than the kerf.
I like Biesmeyer fences (had one on my Unisaw), but much prefer a fence with an adjustable, sliding blade. The blade moves forward and back and clamps to its housing, which moves side to side on the table, setting the rip width. When hand ripping lumber or plywood,I prefer the far end of the fence blade to be in line with, or perpendicular to the center of the saw blade. When ripping lumber with my four-wheel power feeder, I set the far end of the fence blade in line with the feeder's wheel furthest away from the saw blade.
Ripping or crosscutting plywood on a cabinet saw, using its fence to guide the workpiece, is not easy. You should support the workpiece with tables on the in- and outfeed sides, as well as a table on the left side. When feeding the sheet, you should apply feed pressure diagonally across the sheet, toward the fence. Your feed rate should be smooth as you transfer feed pressure from one hand to the other. I begin with pressure toward the fence from my left hand (sometimes wearing a glove) while feeding (with diagonal pressure) with my right hand, and then with both hands as the workpiece end gets closer to the closer to the blade, finishing with diagonal pressure only from my right hand. I rarely let fledgling apprentices rip on the tablesaw, because the procedure requires lots of finesse and can be really unsafe. Vertical panel saws, or sliding table saws are MUCH safer and way more accurate.
"The fence should not be "dead on" parallel to the blade. In fact, the fence should be a few thousandths of an inch further away from the blade's trailing edge...." No longer a "law" of tablesawing, and would not make any difference in this particular problem. I don't want to hijack this thread with an argument about offsetting the fence, so I'll find the last thread that dealt with this, but I'm certain that it's not relevant to this problem.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" .... :>)
Sorry, Forestgirl, but this is pertinent to this thread, because DoubleB was talking about a problem ripping 1/2" and 3/4" thick plywood. I suggest (1) the plywood edge may not be straight, (2) the fence may be out of alignment, or (3) operator skill may be lacking.
As to fence alignment: in a perfect world, perfectly parallel fence and blade would work, but nothing in my shop, at least, is perfect.
Gary,
We'll have to disagree on this point.
I ran fairly rigorous tests trying various amounts of toe in and toe out for a table saw fence while writing an article for a magazine.
I got the best results with the saw blade and fence parallel to each other, with a couple thousandths misalignment to either side making no significant difference. Once you got beyond the couple of thousandths misalignment though, things went down hill. With toe in, I got lifting, burning, and jamming. With toe out the stock could not be kept in contact with the fence on longer cuts without applying excessive force on the stock, again creating jamming, lifting, and burning.
Parallel alignment works just fine and keeps you in the middle of the safest alignment for the fence. Intentionally toeing out risks creating a situation where the toe out might become excessive because of the minor misalignments common to most saw fences in actual use.
For another article, I ran tests on many brands of saw fences that showed they all wobbled a bit in their alignment to the blade depending on where they were along the rail, and this was under ideal conditions of assembly and tune up. In day to day shop use, these fence and saw inaccuracies, combined with an intentional toe out, could combine to create cuts where the toe out would definitely cause trouble.
John W.
You're right: I disagree with the assumptions you made based on your test results.
However, I think we all agree that the saw blade's leading edge should do ALL the cutting. With that in mind, then this is what I've learned about fence alignment after 35 years of ripping lumber and plywood. First, let's assume the fence is to the right of the blade, let's name the workpiece the resultant piece that was between the fence and the blade, and call the piece that falls off from the left of the saw blade the "offcut."
1. Certainly toe-in is out of the question - its a real bad idea, because the saw blade's trailing edge will be cutting UP into the workpiece. That's not only unsafe, but it also results in a less than straight cut through the workpiece. I don't (won't) test that to prove the results.
2. If the fence is aligned perfectly with the saw blade, then operator skill, and the straightness of the workpiece' edge in contact with the fence will determine if the workpiece contacts the saw blade's trailing edge. We're talking plywood here, and I never assume it's got a straight edge, any more than I trust it's perfectly square. After all these years, I'm quite proficient, but I can tell you that ripping a 75-lb, 4x8 sheet of hardwood core plywood is not easy - even when it's edge is straight! So let's make it easier - if you want perfection, buy a sliding table saw with at least an 8-ft slider Back to ripping.....
3. If the fence is toed-out (.002-4") then there's less chance the workpiece will make contact with the saw blade's trailing edge. The only downside to toe-out is that the offcut will likely contact the blade's trailing edge, and that piece may (likely will) need jointing. When I rip 4x8 sheets in half, after checking the long edges for straightness, I first run each of its factory edges against the fence, and then I rip each of those workpieces to width with my fresh cut edges against the fence. I can assure you: if your fence is straight, if the plywood edges are equally straight, and if you keep the workpiece edge tight against the fence..... the result will be a straight, dimensionally parallel workpiece. I should add that you should retract the fence blade to align its far end with the center of the saw blade.
If you're worried about maintaining fence alignment, then you should consider a better fence. Check it often. If it's out, then re-align it. If it flexes, buy a better fence that doesn't flex, or clamp its far end to the saw table after setting the rip width. Cheap equipment yields cheap results. I've used them all from my Dad's Craftsman, through Unisaws and Powermatics and job site Makitas, to Altendorfs and my own Felder. Upgrading has given better results, and I set up all of them with my prescribed toe out. It works.
I hope this helps.
Gary
gwwoodworking.com
Thank you John! You are hereby bookmarked. ;-)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" .... :>)
The blade isn't the problem. I'd look at the splitter, for sure, as mentioned above. You say the 1/4" cut fine, but the 1/2" was off. In addition to checking that the splitter is in-line with the blade, make sure that it's 90-degrees to the table. Stock splitters can often get out of alignment both ways.
Please take care with that 1/4" stuff -- it can "float" up and get caught on the blade. If you find that you're really having to hold it down, causing distraction from the rest of the process, you can clamp a 1/2" thick board to the fence providing a channel for the ply that keeps it from floating upward.
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" .... :>)
Could it be that as you're applying pressure against the fence you're inadvertently "rocking" the ends of the plywood away from it?
DoubleB,
If you are using a Bies knock-off, with fancy plastic face, check and see if your plastic is flat along its length....keeping it against the fense may be causing the bow...
Thanks for all the replies. I think I'll start with checking the factory splitter alignment(I've eyeballed it but I could check it more accurately I'm sure) and I do think a combination of the pushing diaganolly and not rocking the other end away from the fence may help. Also the blade may be getting dull. You now how it is when you use something for awhile...you get used to it as is and forget what it's actually supposed to cut like.
I may splurge on a new blade, always need a reason for new tools right? hahaa
The fence doesn't have the plastic face. It is extruded aluminum and I checked and it is flat along it's length.
Thanks again.
I thought I'd given up long ago on these threads on table saw usage and fence toe-in and fence toe-out, and the benefits of, or lack of benefit in the use of the European style short rip fence as opposed to the US style long fence, but here I am after many years of silence on the subject inexplicably feeling an urge to make a contribution-- more fool me I suppose, ha, ha.
In DoubleB's case I doubt very much that the fence is parallel, or close to parallel to the blade, or the other way about if preferred. The resultant cut he (she?) describes is a classic result of the fence badly toeing out at the rear of the blade, or possibly (if used) the riving knife or splitter being severely misaligned to the left as the blade is viewed from the front.
When the fence is very badly out of line, as in toeing out in this instance, the result is that the material being cut has the cut edge of the offcut aiming towards the blade plate. Once the offcut contacts the plate of the blade, and if it's a substantial offcut, it will follow the line of the plate dragging the dimensioned piece away from the fence. The end result is a curved cut as described.
If the riving knife or splitter is the culprit this can usually be spotted because the offcut part of the piece being cut bangs into the front edge of the knife causing the operator to feel a slight hesitation, or worse in the push through.
Slight toeing out of the fence from the blade shouldn't cause much of a problem, especially if the offcut is thin and easily bent. Toeing in of the fence causes the piece being dimensioned-- the bit of wood between the the fence and the blade-- to aim at the blade plate. If the toeing in is severe enough the cut edge of the piece being dimensioned can engage with the plate causing at best burning, and at worst a complete jam that might result in a kickback as the up-spinning rear half of the blade tries to lift the wood up and back towards the operator.
My advice to people setting up saws for ripping operations is to set the fence parallel to the blade, but knowing this is near enough impossible to guarantee it's preferable that the fence toes out just a thin bo'hair rather than toeing in.
Incidentally, there are plenty of discussions from five or six years ago on this topic that I did get very involved in and might be worth seeking out using phrases like 'table saw fence alignment', 'short rip fences', 'European saw rip fence', or perhaps European style riving knife and crown guard' and my old registered handle of Sgian_Dubh, although old posts from those times may now be merged with my new SgianDubh moniker.
Right. That's it. Ah'm off to ma' pit as it's after midnight here. I'll leave most of you all to fight it out in Americaland time whilst I slumber, ha, ha. Slainte.
Richard Jones Furniture
Not to raise my favorite subject, but it is relevant here. I like my table saw, but I never use it to cut full sheets. For that, I use my Festool saw with guide rail. Way more fun, better results, safer, and portable!
Matthew, I'd have to agree that breaking down sheets of man made board on a typical US style cabinet saw (or any other saw with small fixed tables) can be difficult and your method has lots of merit from a safety angle.
The Festool system seems to be well thought of amongst those that own one, and geting the parts down to manageable chunks adds to safety in saw table usage.
Of course panel dimensioning is made easier again if you happen to own a big sliding table saw with scoring blade, but not everyone's got one of those kicking around the workshop, ha, ha. Slainte.Richard Jones Furniture
Sgian,
When I joined here I remember 'Sarge' thanking you for your suggestions on the Euro rip fense. I remember because I couldn't figure out what ya'll were talking about. Anyhow, now all those old discussions appear to be gone..sigh...hint, hint.
Ah, the short rip fence debates BG. There have been plenty of those over the years that I've been involved in. I use one all the time-- it's a legal requirement here in the UK anyway to rip wood fed by hand with a short fence. There are good reasons for that requirement with one of the major ones being the increased safety the short rip fence brings to the operation.
Still, this is not a discussion on that particular topic so I'll let it pass. Slainte.Richard Jones Furniture
I have a question about a using a short fence.
As you reach the point where you are ripping the last few inches of the stock, you also have only a few inches of the board against the fence making the stock hard to control. With no fence on the outfeed side the there is nothing to steady the stock against and the far end of the board can veer left or right. It may not be that important, but I certainly don't like the wobbling that occurs with the last few inches of ripping with a short fence. It occurs to me that a short fence combined with a true riving knife might solve this problem, but I've never used a saw set up that way.
John W.
John, I suppose the best way to see how this works is to watch someone that knows how use one of those European style saws with the the short rip fence, crown guard and riving knife for ripping. I've a lot of experience doing this with saws ranging from smaller than 3 HP jobs up to about 12 HP. The wobbliness of the wood you're concerned about just isn't an issue in practice.
To be honest when I first witnessed standard US style ripping with a long rip fence and a completely exposed blade it gave me the willies, ha, ha. Slainte.Richard Jones Furniture
Richard,
Could you describe the technique of ripping with a short fence? What does keep the workpiece precisely referenced to the blade as the amount against the fence diminishes to nothing toward the end of the cut?
Rich
I thought they got away with a short fence because they had sliding tables. If they guide freehand I don't get it either.
vulcan666,
I think, not positive, the short fense goes almost to the back tooth on the blade....and in combination with the riving knife keeps all steady. However, I don't see it working very well with a straight edge to square up one edge of the stock.
Just me with a ECheepo TS.. I cut ALOT of 4 X 8 sheets.. Up to 1 1/2 inch thick.. My fence is towed out about 1/16 inch on the exit end..Fence gets it there.. Blade and that thing behind it keep the rest straight.. Well, as long as you have good support for the cutoffs!I have found that good support for the wood is as critical as ANY of the saw settings..
Rich, rather than clog this thread up with a divergent topic I'll start a new one called 'Alternative technique for rip sawing' in reply to your request for information. Slainte.Richard Jones Furniture
Richard,Thanks!
YES! But we like living on the 'EDGE'... LOL
Hi John,
The advantages of a "short" fence became obvious soon after I tried the one on my then new Felder KF700. I'd spent thirty years with typical American fences, half of them with a Biesmeyer fence. My European style fence isn't really short, measuring a meter long - it's retractable. Old dog that I am, I began using my new machine's fence with its end aligned with the back of the saw table. Then, a few years ago, I tried retracting the fence after reading a thread here by Richard Jones (Sgian) on the subject of tablesaw safety when ripping. It took some getting used to, steering sheet goods without the fence behind the blade, but I soon caught on. Now, for all hand ripping, I use a splitter and retract the fence so its end aligns with the center of the saw blade.
Try it by attaching a 40-inch piece of plywood to your Biesmeyer fence, aligning one end with the center of the saw blade. Remember that the front of the blade is doing the cutting and that all your diagonal feed pressure toward the fence should be directed in front of the blade. As the workpiece nears the end of the cut, you can apply less pressure toward the fence and focus on steering the piece straight. As with any other woodworking task, you'll need to practice..... or as Sgian suggested, find somebody to watch.Gary
gwwoodworking.com
What the hell is going on in A merica??? What with the selection of single phase voltages (all under one roof) we now witness an attack of fence wandering.
Strangely enough , despite all predictions to the contrary, I have escaped this problem, even though my Delta cabinet saw is almost 50years old and still has the original equipment ffence, which I ssimply adjust by the bbump and mmeasure method*. No burn marks, rising thin sheets , kick backs or taper cuts and I have yet to salute that saw, respectful as I am.I always allow a mm or so for the jointer .
Just thought I'd get a word in here.
* However, the measuring is a double check for correct width, rather than fence //ism, because I must have that lever do what it is supposed to do-pull the fence square across the table!
How do you check to see if the fence is parallel to the Blade?
The T-slot and the blade may not be parallel, as most people set the fence to the T-slot.
Hilmar
Himar, from you that must be a loaded question, so my answer is "with some initiative".Philip Marcou
It should read " How did you check...."
No loaded question, why did you say that?
I don't know his saw,don't know how old it is ?
Not every saw blade is parallel with the 'T-slot"
The table may be off slightly off.
If I stepped on some one's toes, sorry.
The question was meant to "double B"
Hilmar
Edited 10/9/2005 11:02 pm ET by h12721
Edited 10/9/2005 11:04 pm ET by h12721
No Hilmar, I was just funning you. There are so many ways to confirm or otherwise check that the blade is //to the slot, with or without instruments or even a steel rule.The fanatics will dig out the dial gauge, but I don't think it is that critical.
What we need to find is the smartest way of aligning blade to slot....
Philip Marcou
I always thought that if the blade (A) is aligned with the miter slot (B), and the blade and fence (C) are also aligned, then the fence is aligned with the miter slot. You can substitute (A), (B), and (C) any way you wish.
If A=B and B=C, then A=C?Probably, I'm missing something. But this is how I aligned my saw. Plus, being the obsessive that I am, I check the alignment regularly.
Edited 10/12/2005 7:12 am ET by MatthewSchenker
Is there a Question in your post?
No you did not miss a thing.
Hilmar
That is how most of the guys I know do it as well. There are more chances for error, but if you set the blade to the slot accurately then setting the fence becomes super easy.
Mike
mudman,
Matthews way is adequate till you've got problems. Personally, I check the full length of the fense against the miter slot with a straight edge that fits in the miter slot..it get me a lot closer to that Bo'hair toe out...and captures any indentations in my fense.
DoubleB & All ,
Much good information and many opinions have been given on this thread . Several of the tidbits imo are paramount and probable causes . First off every now and then the factory edge on plywood is not really flat , and some fences may be less then flat as well . The fence to blade alignment , not table slots is to me the key . Also I keep a thin coat of paste wax on my table tops , my tops are particle board , if you have laminate type table tops maybe no wax is needed . Honestly the difference feels like 2 sheets are being pushed thru instead of one , so obviously much less pressure is required to push the panels , therefore less opportunity to go astray imo .
regards dusty
UPDATE:
Well, I did some more cutting last night and more checking. The miter slot is parallel with the blade(used dial indicator) and the fence is toed out ever so slightly(less than 1/32"). I checked the splitter with a square and it is aligned with the blade as well.
I was ripping red oak with my Freud rip blade which hasn't had much use so I know it's sharp. And low and behold I DO get the "hollow" in the middle of the board!!! I tried several different methods. I was using a Benchdog feather board and on I adjusted the pressure to see if that made a diffference. Then I removed the splitter(I know I know) and even thought the low area seemed less it was definitely still there.
I thought maybe it was stress in the board so I cut some plywood, nothing wide just like 4" wide strip cut to 2". same thing. It's consistent.
So, I lifted the fence off and layed it on my bech and layed my straight edge on it and low and behold my fence has nearly the identical low spot in the middle of the length. (It's not my starightedge because when I run boards throught the jointer the straightedge does lay flat along the length of them). The fence has an extruded aluminum face. So I have two questions....one, Wouldn't a low spot on the fence cause the board being cut to have the opposite result I'm getting??? Two; What are my options now???? How do I get a low spot out of the extruded aluminum face??
I do live only a few minutes from Wilke Machinery so I will go to see them since I bought it there. I can't believe I didn't realize it before!!! When I checke the flatness of the fence I had always checked it while it was on the saw and with no light coming from the other side I couldn't see the low spot.
Actually a low spot in the fence would cause exactly the problem you describe. Think about the path that the leading edge of the ply takes. First it is on the "high" part of the fence then it rides into the hollow, then when the leading edge starts riding up the high spot (out of the hollow) the blade is probably cutting in the middle of the board. At this point the work piece is moving laterly into the blade and cutting it narrow. when the trailing edge hits the low spot the workpiece moves away from the blade widening the cut again.
On another note, weather you subscribe to the toe out practice or not, 1/32" is a lot more than what is commonly used. I used to do the toe out method and would toe out a hair, mabey 1 or 2 hundredths. Now I set it all straight and parallel, that works better for me. I haven't seen any blade or saw manufacturer recomend toeing in. If you are not sure ask CharlesM. He works for Freud and is the go to guy for all things cutting.
Glad you found a likely culprit. fix it before you have to fix a finger or worse.
Mike
DoubleB, it looks like you've found the fault, and a bent fence as you describe will cause the problem you originally posted about. A bent fence was a fault I forgot to think about in my original post and my diagnosis of the problem was obviously incorrect because it limited possible causes of the problem.
As you seem to live close to the supplier hopefully the solution is at hand, particularly if the item is still within the warranty period. A new (straight) fence should do the trick.
Now, if the fence was bent convex away from the blade that could also lead to some interesting problems, especially if you had been relying on it to guide material over a dado blade or past a router cutter. Slainte.
Richard Jones Furniture
Edited 10/12/2005 1:27 pm by SgianDubh
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