Table saw blade changes front-back angle when tilting.

[George Gyulatyan]

Creekers, need help figuring out this one.

I am making a new crosscut sled. I made two plunge cuts one at 90-deg another at 45-deg to figure out where I am going to route for zero-clearance insert I intend to make for this thing. After making the cuts, I could tell that the front and the rear of the two cuts are at slightly different angles. Measured with calipers, there is a 0.01" difference between the two cuts.

Any idea how I can correct this? Or should I bother? And more importantly how can I align the fence? Should I just not bother with the blade and align the fence to the miter slot (both slots are covered by the sled, so will need to align to the rip fence I suppose).

[Bill Orbine]

What is your table saw?

[George Gyulatyan]

Jet JPS-10TS ProShop

[David Kumm]

Usually the table is not flat relative to the arbor assembly and blade. High or low front to back or with a twist. I use a master machinist level to determine if the table is reading the same at all corners and in all directions and then work from there. Dave

[Lee Schierer]

Maybe I don't understand the question, but normally you align the blade to the miter slot and the fence to the same miter slot. There are procedures for aligning the blade when the blade moves out of alignment when tilting. I am not familiar how to do that on a Jet saw.

[glenn bradley]

This is corrected during initial alignment. For cabinet mounted trunnions this is pretty simple (shim front or rear to correct relational planes). For table mounted trunnions you have to really, really want it but, it is achievable.

Granted, a lot of folks align their saw at 90* and call it good. This is fine as long as you don't mind burning and don't want to do any accurate bevel work. Once the blade is aligned at 90*, tilt the blade to 45* (or some sizable angle) and re-check.

If the rear of the blade is closer than the front per your measuring device, lower the rear of the table (or raise the front). The opposite is done for the opposite error obviously. this alignment is so often skipped. Let me see if I can find a guide that illustrates what I am doing a poor job of saying ;-)

Hmm, I've checked 5 different online methods and all of them fall short of setting up the blade alignment at a bevel. I'll keep trying . . .

[George Gyulatyan]

Yeh. Unfortunately in this case the trunnion is mounted to the table, which is gonna make it a major PITA to get this aligned. I do have a project coming up where I am gonna need accurate miter cuts or things are gonna look terrible. Parts are also going to be about 11" wide so alignment errors will be exaggerated.

I think I'll give Jet a call Monday.

Thanks for pointing me in the right direction.

[Bruce Wrenn]

American Woodworker ran an article "Super Tune Your Table Saw" many moons ago, which covered this procedure.

[Jerry Bruette]

Bill Huber had a thread about this problem with a very good explanation of the solution.

I made a bevel sled to avoid the problem on my Craftsman contractor saw. Blade stays at 90, piece is held at 45 while cutting.

[Metod Alif]

Glenn,
I think that shimming the table is a good way to solve the problem. In short: The axis of blade rotation needs to be parallel to the miter slot (I am just repeating what is said a while ago about the same problem).
For this, the actual location of the axis is not important - it does lead to the adjustment steps:
Bring the table so that the miter slot(s) are parallel to the blade. Then make a test cut with the tilted blade. If satisfied, stop. If not, start shimming. Make sure that the blade is still parallel with the slots after each shimming. A repeat or two, and it should be OK.
Best wishes,
Metod

[glenn bradley]

Well, it is not totally thorough but, here is an old post of mine (http://www.sawmillcreek.org/showthread.php?111878-Blade-to-Miter-Slot-Alignment-Cab-Mount-Trunnions) where I went through the process. Unfortunately this is for cabinet mounted trunnions but, the concept is there.

[john bateman]

I have a different saw, but the trunnions are mounted to the underside of the table. I had about the same amount of heel as you are getting.
I had to insert shims of about .03" between the table and trunnion mounts at the infeed side to get rid of the error. In my case the rear of the blade was further away from the rip fence than the front of the blade was, by about .012".

Doing this was a total PITA as each attempt to correct it causes the 90 degree alignment to change also. But there was no other way to make the saw cut bevels without burning or pulling the stock away from the rip fence.

[Chris Merriam]

The Sawstop manual runs you through this adjustment, and it states that you will throw off the 90 when you do it. So chase your tail until good enough or you lose patience. I think I repeated the 90+45 setup like 4 times.

[Roger Davis]

Jerry,

Can you post a picture of your bevel sled as I am having the same alignment issue with my Unisaw.

Also, how do you clamp the piece to be bevel cut to the sled and do you cut the pieces to length at 90 degrees and then bevel cut each end with the sled?

Roger in Texas

[Jerry Bruette]

Roger

Here are some pictures of my bevel jig, in all it's ugliness. It clamps to my crosscut sled which rides true to the blade in the miter slots.

Yes I cut the work pieces to length at 90 then bevel them. I have to place a spacer at the bottom of the work piece, that's equal to the thickness of the jig's bottom, while clamping the piece to the jig.

First picture shows piece clamped to jig, second shows how jig is clamped to sled, third shows jig with no piece clamped.

341437341438341439

[Roger Davis]

Jerry,

Thank you for thr bevel sled pictures. I will build something similar to attach to my crosscut sled.

Roger in Texas

[lowell holmes]

I remember having to adjust the trunnion on my Delta Contractor saw. It was not that big of a deal. Just make that an afternoon's project. Have a proper mallet ready to use. A 1x1 stick that has a proper length for the problem is handy as well.

[Jon Nuckles]

The Sawstop manual runs you through this adjustment, and it states that you will throw off the 90 when you do it. So chase your tail until good enough or you lose patience. I think I repeated the 90+45 setup like 4 times.

For the OP and others without a Sawstop, be aware that the Sawstop has adjustment ability to correct for this problem without shimming. In other words, don't bother looking for a Sawstop manual to guide you to a correction procedure that will work on your saw.

[George Gyulatyan]

Thank you all for the great responses! I looked at the Jet manual and it suggests I turn the whole saw upside down to get to adjust the trunnions!

I like the bevel sled idea. I think that's what I'll go with, although I will still need to make some long beveled rip cuts... will test on some plywood to see how that goes, before I ruin the veneered panels :D

For completeness sake, here are the pictures of the measurements:
341570 341571

Thanks again,

George