Tablesaw blade alignment problem

[Greg Woloshyn]

I have a Delta contractors saw and I'm having a problem with getting the blade aligned correctly to the fence. When I'm ripping a piece as soon as it gets to the other side of the blade (end of cut) the back teeth cut into it. I used my dial indicator in the miter slot to ensure my blade was aligned to the slot which it was, and so was the fence! Both appear to be aligned within a few thousandths. The freud blade is fairly new and clean and runs true. What else am I missing?

[Paul K. Johnson]

I have a DeWalt contractor saw and the rack and pinion for the fence had weird play. If I moved the fence out then the front of the fence would be farther from the blade than the back of the fence. If I moved the fence in then the front of the fence would be closer to the blade.

I finally adjusted the blade to be parallel when moving the fence in so any time I needed to move the fence out I moved it too much and then back in to the final setting.

You might have a similar issue where the fence aligns differently depending on whether you're moving it in or moving it out.

[glenn bradley]

Paul may be on to something. You say the blade and fence both align to the miter slot. I assume you have rigged something up to slide in the miter slot while an indicator rides the fence. This same rig could be used to touch the same spot on the blade with that spot rotated forward or back. Once all that checks out, position the rig to check the fence, slide the fence a foot or so to the right and then return it within measuring distance, lock it down and re-check. Are things still good?

[Andrew Hughes]

Check to see if the fence is flat.If it curves inward at the end you might have to adjust it out more.

[Lee Schierer]

It sounds like you have a fence clamping issue. Many OEM fences don't always clamp down square on the table. I had that problem for years before I switched to a Beismeyer fence. I've had no issues since.

[Greg Woloshyn]

Thanks everyone for the help, I'll be checking the fence out tonight and see what I have. The did check the fence to make sure it is flat and square.

[Greg Woloshyn]

Well, I tried everything suggested here and still cannot solve the problem. I used my indicator to verify blade alignment to miter slot using the same spot rotated front to back (checked within .002) and the fence is also within that spec, rechecked in different spots.

I hate to move my fence outward away from the blade if it checks parallel to everything else just to try and correct the problem..

Here is a video where you can see towards the end of the cut wood chips fly up indicating the back teeth are cutting..

https://youtu.be/ZHdaphYZcmo

[lee cox]

If it checks to .002 out I don't see how this could happen. You probably need to check the blade on all the teeth. The other thing I would do is run your indicator up and down the miter slot and check the whole length of your fence. I think something has to be out more than .002 to cause your problem. I guess one other thing is you could be pushing the board crooked to cause a bind.

I have never seen a fence .002 out. I worked on my fence for a while and ended up using European Baltic birch plywood to get it to .005 out on the full length of the fence on my Unisaw. It was the best I could do. My blade is .002 or less out.

[Paul K. Johnson]

OK, I see several ways this could happen. If the board is bowed even a little then if the concave side is against the fence then the board exiting the blade will contact the rear teeth in most cases.

The blade could be warped or have some problem with the teeth.

The arbor bearings may have a problem that only show up under load.

Have you tried a different blade?

[Greg Woloshyn]

The boards are jointed square before I use them so I know they are running straight. I tried two different blades and got the same result - so it can't be the blade.

When I pull on the arbor with the blade off, the bearings feel tight and sound fine - but there is some noticeable play in the pinion gears for adjusting up and down, and left to right. Gears should have some clearance though. I'm wondering if this is causing the blade to move around in the cut.

[Doug Garson]

I notice you don't have splitter or riving knife and it doesn't look like it in your video but is it possible when you push the wood thru you aren't keeping pressure against the fence and the wood is moving slightly away from the fence? Try adding a shop made splitter to prevent this.

[Bill Space]

As Doug said, perhaps it is a technique issue.

I have been following this thread and wondered what I might do I do if I had the same problem.

Do you have a thickness planer? If not then what I am about to suggest has no value…

I have a planner so what I would do is first joint a piece of wood and come up with a straight edge, and then I would pass it through my thickness planer on edge, so that I had a piece of wood that had two parallel sides.

Since you believe the back end of the blade is cutting the wood, that means that the back end of the blade is closer to the fence than the front end of the blade.

I would pick one edge of the board and put a lot of pencil marks on it. I would then adjust the fence so that the front edge of the blade was just missing that side of the wood. In other words, the front of the blade would not cut the wood, but the wood would pass very close to the blade teeth.

I might push the wood halfway through the blade just to verify that the front of the blade was not cutting the wood.

After verifying that the front half of the blade was not cutting the wood, I would push the wood all the way through, past the blade, and take a look at the pencil marks, and see what was removed and what was not.

If it turned out that all the pencil marks were removed, then I would conclude that the fence was tilted in towards the blade at the far end.

If The pencil marks were only removed from the back of the test piece, then I might conclude that my technique was at fault.

If none of the pencil marks were removed I would repeat after moving the fence slightly closer to the blade until I had some definitive information.

Just what I would do to zero in on the problem. Ymmv 😀.

Bill

[Chris Parks]

Slightly toeing out the fence should fix this as well as being a safety measure against kickback. Where the idea of having the fence absolutely parallel ever came from beats me as it is the saw blade that guides the wood after the cut is started. I know that is an heretical idea around here but when some though is given to it that is what happens for most of what we cut.

[Greg Woloshyn]

Sure, I can try to correct it by adjusting the fence and blade out of parallel to the miter slots, but I shouldn't have to and it doesn't seem like the right fix. I've been loosing the blade mount underneath and tapping it in to get it parallel to the miter slot where it should be.

[Chris Parks]

I will repeat what I posted above and even add to that, the fence SHOULD toe out slightly and not be parallel if only for safety reasons and nothing else. No European saw has a fence that extends past the leading edge of the blade because it is not needed and is in fact dangerous. Can anyone tell me what is the big deal with a parallel full length fence is?

[Eric Schmid]

If you are confident in your alignment measurements, blade and cutting technique, something may be causing your blade to deflect in the cut. When the board is at the end of the cut the tension releases, returning the blade back to 90.

Deflection could be caused by a bad arbor bearing or warped flanges, tough wood, thin kerf blade, dull blade, etc.

What happens if you cut down the middle of a larger piece? Do you have a full kerf blade to try?

I keep my fences kicked out a little on the outfeed side. Cuts turn out just fine and no backside blade nicks.

[Doug Garson]

Another thought, European style saws, I understand have short fences where the fence ends at the front of the blade. You could try a short fence by attaching a strip to your fence that stops at the front of the blade (maybe someone with a short fence can clarify exactly where it stops or a google search can ). If it solves your problem it would indicate the fence is the issue. If not it is likely a blade or arbor issue.

[Chris Parks]

This explains it....http://www.popularwoodworking.com/woodworking-blogs/table-saw-safety-why-the-british-think-were-crazy

It is a European thing not a British thing though who knows who had it first.

[Bill Space]

I have a Delta contractors saw and I'm having a problem with getting the blade aligned correctly to the fence... What else am I missing?

Let's start over. You do not align the blade to the fence. You align the fence to the blade. Semantics? No...reality.

So you align the table miter slot to the blade, then you align the fence to the blade. (Or to the miter slot if you got that right to begin with).

If you think you align the blade to the fence...pause...take a breath...and reconsider.

Since you are apparently only experiencing this issue at the end of your rip cut it is most likely a tenique issue.

You will continue to chase your tail unless you decide to make some tests that can lead you to understand the reason for the problem.

You need to quantify the issue.

I have a delta unifence and can set it so the front end of the fence, when ripping, is at the front edge of the blade, or wherever else I might want to position the fence. But it really does not seem to matter with a well tuned saw and a riving knife. My fence extends beyond the blade for the most part. Without issues.

So is your issue technique or something else. Measure and evaluate...

You stated your fence is not bent. So how can a straight fence and good blade only cause an issue at the end of the cut?

Technique? Probably...

[Greg Woloshyn]

If you are confident in your alignment measurements, blade and cutting technique, something may be causing your blade to deflect in the cut. When the board is at the end of the cut the tension releases, returning the blade back to 90.

Deflection could be caused by a bad arbor bearing or warped flanges, tough wood, thin kerf blade, dull blade, etc.

What happens if you cut down the middle of a larger piece? Do you have a full kerf blade to try?

I keep my fences kicked out a little on the outfeed side. Cuts turn out just fine and no backside blade nicks.

This post most explains what I'm dealing with. The blade deflects and returns back to 90 after the cut but leave blade nicks on the bottom edge.

I'm not certain that it's my technique, I've been using this saw for years and never ran into this issue until recently. And I've actually been using pine to test with (since I don't want to waste my good wood).

Perhaps it could be a bad bearing in the arbor, although there doesn't appear to be.

[Floyd Mah]

Check to see that the front rail of the fence setup is straight. This is the rail that the fence clamps to. The reason I mention this is that you mentioned "contractor" saw. I started with my Delta contractor saw many years ago and began the process of upgrading it by bit by bit when I discovered that my cuts weren't what they should have been. Ultimately, it turned out that the front rail of the fence, which was a tube, deformed when bolted tightly to the cast iron. Literally, I had a bowed front rail. The fence's alignment with the saw blade varied with the width of the cut I was attempting to rip. The bowing was caused by the mounting bushings. I should have been more care to check, and adjust, the thickness of the bushings, but who would have thought that would happen?

[lowell holmes]

I would try cutting 1/32 to 1/16" over size and ripping to final width.

[Greg Woloshyn]

Had the chance this past week to tear down my saw and check out the bearings. They are smooth and tight, so I didn't pull them off the shaft. I cleaned and grease the trunnion assembly and reassembled the saw. Still having the same issue. Something I did find is that the blade cuts great using the miter gauge, it's when I use the fence it back-cuts and deflects. This test was done using a full kerf blade, with my blade aligned to the miter slot and then my fence aligned to that same miter slot.

[Brad Barnhart]

Bein' old school, & runnin' a high chance of rufflin' feathers of them fellers w/dial indicators, & all that, I'm goin' to throw in my two pennies worth & see if I pull back a bloody stub.
Let's start again. You're tellin' us your saw is chewin' wood at the end of the cut. You've checked arbor bearings, blades, miter slot run out, etc.
Ok. The one thing you didn't mention was whether or not you put a square to your fence once you've set it. Is it square with the saw table? Have you laid a level across the top of your fence? down the side of it? It's possible there may be a slight bow in your fence? What about layin' a square down your miter slots?
Are you usin' a thin kerf blade? Or a rip blade? If you're usin' a thin kerf, you may need to make adjustments to your blade. Are you over tightening the blade?
How are you standing at the saw & feeding material into the blade? Behind the saw? Beside it? I've found, as short legged as I am, I get better results & straighter, smoother cuts by standing to the back of the saw, just off to the left side. That way I'm out of the line of fire, & can keep constant pressure downward & toward the fence. You may have to make some adjustments in your technique. And I agree with checking the fence rails. make sure they are straight & square. A suggestion, try a sacrificial fence(1/4" plywood)against your present fence. Joint & plane both faces & edges of your test piece. Snap a chalk line along the cut side. Set your fence & see what the result is. If you get a full, straight cut with the sacrificial fence, you've got your answer. Square it w/a square before you make the cut. Then you'll know.

[Andrew Hughes]

I think it's the fence too.All saws have fences that are not flat and flex.Have you pushed on the end of the fence too see if it moves.
Maybe I should not try to help I can barely figure out my saws quarks.

[Brad Barnhart]

one thing to keep in mind, you're dealin' with a contractor saw. So, with that said, the fences on most of them aren't top quality, nor designed for perfection. You can make improvements to it to make it stronger, & more accurate, but they do have their limitations. But the more Ive read your post, & reread the other posts, I still think it's your fence.

[Lee Schierer]

I looked at your video again and noticed that your blade is pretty low when you are making rip cuts. As a general rule, the gullets should be above the surface of the wood when you are making the cut. In addition, the higher the blade when making rip cuts, the more downward pressure there is on the wood so there is less chance of the wood climbing up on the blade and creating a dangerous situation. It bothers me that the off cut came back toward you at the end of the cut. It shouldn't do that if your saw is properly aligned.

[Robert Engel]

I've seen warped fences........

[Greg Woloshyn]

PROBLEM SOLVED. Thought I would post an update that my problem appears to have been fixed after I took off the stock worn out belt and put on a new link belt. Wow, the saw runs so much smoother, quieter, and hardly any vibration. Maybe that was causing the blade to wobble? The belt was pretty worn out, I just didn't notice it getting progressively worse over time. Also, as someone mentioned here, technique may have been a factor. I switched to these MDF zero clearance inserts and I might have been putting too much downward pressure on the workpeice through the cut, and causing the insert to bend. Thanks to everyone for the help - glad it's fixed for now.

[Lee Schierer]

I'm glad you got it fixed. You can add a stiffener rib on the bottom side of your zero clearance insert that clears the blade and adds the required stiffness.