Contractor's Saw - Can't Maintain 90-Degree Cut

[Leo Butler]

I recently started working on squaring up some stock for a small benchtop as part of a moxon vise I'm building. I cleaned up a face and squared an edge to it using hand planes (on several boards), then ripped the second edge on my old Rockwell 34-348 model 10 contractor's saw. I had just recently squared the blade to the miter gauge slot and then calibrated the 90-degree stop, being careful to use c-clamps to keep the trunnions and mounts tight together. But upon checking the first couple of boards, the edges weren't square any longer. I have since loosened up the stop, and every time I change the blade height I do a test cut and tweak the angle until it's 90 degrees then lock it down and do my final cut.

Obviously this needs to be dealt with. I have no problem tearing into the saw and checking things out come the holidays, but I wanted to ask if there's something specific that I should be looking at that could cause this issue.

Also, I had just recently made peace with my desire to upgrade to a new/newer table saw (I've had this one for 25 years) and as I'm more interested in making things than rebuilding my saw, I'm revisiting my decision. Should I expect to be able to get this saw to an acceptable level of precision for (reasonably) fine woodworking? It's the only saw I've ever owned so my expectations aren't necessarily well calibrated with reality.

Thanks,

- Leo

[glenn bradley]

There will be other opinions on this. I made a lot of nice stuff with a contractor saw BUT, I always found other ways to do anything other than a 90 degree cut. You can get decent table mounted trunnions to align at 90 but, by the nature of the design, nearly all contractor saws show misalignment during bevel cuts. I even went through the process of getting my saw to align at 45 degrees only to have it hit and miss once returned to 90 and then beveled again. The trunnions and carriage just aren't stout enough to resist the weight of the motor in that position.

It sounds like your saw is not maintaining 90 degrees when just lower and raising the blade. Is that correct?

P.s. The 90 degree and 45 degree stops are fine for framing a house but, not really much guarantee for the accuracy you seem to be looking for. I always double check my angles.

[Leo Butler]

It sounds like your saw is not maintaining 90 degrees when just lower and raising the blade. Is that correct?

Hi Glenn,

That's right. I have a zero-clearance insert that I seldom remove and all I had done was to raise and lower the blade a few times before deciding to check on the right angleness of the cuts again.

P.s. The 90 degree and 45 degree stops are fine for framing a house but, not really much guarantee for the accuracy you seem to be looking for. I always double check my angles.

I actually don't do many angle cuts on the saw, other than those that use a miter sled. I'd build a jig if I needed a non-90 degree cut reliably, based upon previous experiences that are likely similar to yours. If the blade did nothing other than raise up and down I'd be fine with that, as long as it stayed true otherwise.

[glenn bradley]

OK, so that's actually good . . . My first instinct given what you are seeing would be to look for something that has gone loose or broken. Sounds like you don't haul the saw about for jobsite stuff so probably not a cracked casting or broken mount (fingers crossed). That leads me to look for something that has worked loose slowly over the years (or just worn out) and is finally exhibiting the misbehavior to the level that it is noticeable.

It appears the tilt and height adjustments lock via the wheel knob for each so there's no extra lever to check. The tilt screw on this sort of saw generally has a ball or pivot mount where the screw, or rod, pierces the saw body sheet metal. That is, between the side wheel and the saw's interior. This area can "beer can" fail due to years of stress so I would look there for any cracks, loose screws or failed rivets.

If that area is good we go to the point that the screw meets the trunnion. I understand that you do not bevel often but, we are looking for anything in the structural path that keeps the blade traveling up and down without deviating so bear with me.

The tilt mechanism terminates in a worm gear. Inspect the area that this gear engages the front trunnion (toothed swing arm thingy) for wear, slop or any shifting under stress (provided by you; grab it and try to move it and), watch for movement where there shouldn't be any. Let us know how you do and we can take the next steps.

The machine has given you a good long period of service. It is not really unreasonable to look into replacing it if extensive repairs are needed. This decision has no right or wrong. If worn out or damaged you may want to repair it for sentimental reasons but, (no offense intense whatsoever) I would hesitate to put too much money or effort into that particular saw if you have been considering a new one.

[Jeff Monson]

Leo, this may be of no help, but I installed these on my contractors saw in the days that I owned one. They helped a ton for adjustment and keeping the trunnion deflection to a minimun.

https://www.amazon.com/Precision-Ali...56653074&psc=1

[Thomas McCurnin]

The PALS system helps stabilize the saw when adjusting the trunnions but does nothing to prevent the trunnions from getting out of alignment.

I went through 2 contractors saws in 10 years (Sears, Delta) before getting a cabinet saw. While repairing your saw is possible, I think it’s time for a replacement.

[Leo Butler]

It appears the tilt and height adjustments lock via the wheel knob for each so there's no extra lever to check. The tilt screw on this sort of saw generally has a ball or pivot mount where the screw, or rod, pierces the saw body sheet metal. That is, between the side wheel and the saw's interior. This area can "beer can" fail due to years of stress so I would look there for any cracks, loose screws or failed rivets.

The sheet metal where the angle adjustment wheel is mounted is perfect. I've seen pictures of exactly what you're describing and my saw has not even a hint of that.

If that area is good we go to the point that the screw meets the trunnion. I understand that you do not bevel often but, we are looking for anything in the structural path that keeps the blade traveling up and down without deviating so bear with me.

The tilt mechanism terminates in a worm gear. Inspect the area that this gear engages the front trunnion (toothed swing arm thingy) for wear, slop or any shifting under stress (provided by you; grab it and try to move it and), watch for movement where there shouldn't be any. Let us know how you do and we can take the next steps.

DING DING DING! Yeah, there's the problem. When I grab the two tubes that join the trunnions near the front trunnion and try to move it left/right, IT MOVES. The teeth that engage the worm gear have far too much clearance. I'm going to find some of the table saw tune-up guides to look into this, but as far as you know, is this correctable without part replacement?

The machine has given you a good long period of service. It is not really unreasonable to look into replacing it if extensive repairs are needed. This decision has no right or wrong. If worn out or damaged you may want to repair it for sentimental reasons but, (no offense intense whatsoever) I would hesitate to put too much money or effort into that particular saw if you have been considering a new one.

Yeah, I'm torn. I can afford a new saw but there's a lot of time to invest in getting it, setting it up and dialing it in, dealing with any issues, etc. and that's more of a time sink than I really want to contemplate, ya know?

[Leo Butler]

Leo, this may be of no help, but I installed these on my contractors saw in the days that I owned one. They helped a ton for adjustment and keeping the trunnion deflection to a minimun.

Thanks, Jeff. I read about those in an older post but the link was stale. Glad to see Peachtree still sells them. If I can work out the accuracy issue, I'll get a set.

Looks like you only put them on the rear trunnion. So adjustment must still be the same, meaning on the front trunnion you loosen one bolt more than the fourth one so that it's a pivot point, then use the PALS to dial in the alignment. Sound about right?

[Leo Butler]

DING DING DING! Yeah, there's the problem. When I grab the two tubes that join the trunnions near the front trunnion and try to move it left/right, IT MOVES. The teeth that engage the worm gear have far too much clearance. I'm going to find some of the table saw tune-up guides to look into this, but as far as you know, is this correctable without part replacement?

I just went out and spent some quality time looking at the mechanism, and it appears to me there's no adjustment for the backlash on this saw. There's maybe 20-25 degrees of play in the trunnion tilt wheel due to the engagement (or lack thereof) of the trunnion teeth and the worm gear.

I found a nice tune-up article from an old Shop Notes article and they talk about backlash adjustment in the trunnion assemblies, and show a nice picture of how it's done. My saw doesn't have the mechanism they show, just a stop collar on the shaft. I don't see any way to change the amount of engagement of the teeth/gear.

What I've done is to adjust out the 90 degree stop such that I'm getting a square cut. I tightened the hand wheel while holding it so the 90 degree stop is definitely engaged, and I've done this several times, raised/lowered the blade height, and it seems to be cutting a consistent square edge. I think I wasn't holding the hand wheel like that previously, so the blade could have been backing off a bit.

So I think I'm good for now, and I'm going to keep my eye on Craigslist for a new (to me) saw that has the features I desire.

[Lee Schierer]

Saws that rely on stop collars to control tilt angles are unreliable. Saw dust gets on the shafts and can get compacted against the stop creating errors. Many years ago when they first came out, I purchased a Beall Tilt Box. I use it any time I move my saw off 90 and again when I return it to 90. Since I started doing this with my contractor saw, I've had no alignment issues making cuts. For $42.50 they are well worth the investment.

[Leo Butler]

Saws that rely on stop collars to control tilt angles are unreliable. Saw dust gets on the shafts and can get compacted against the stop creating errors. Many years ago when they first came out, I purchased a Beall Tilt Box. I use it any time I move my saw off 90 and again when I return it to 90. Since I started doing this with my contractor saw, I've had no alignment issues making cuts. For $42.50 they are well worth the investment.

Lee, I discovered today that my Forrest Woodworker II has a dished shape on the steel face. I was attempting to use a triangular setup gauge to check the blade angle (against the steel, not against the carbide) and there's a significant gap in the middle part of the blade vs. the straight edge. I think this would render theBeall gauge unreliable as well.

In any case, with the backlash problem my only recourse to keeping the blade vertical is the stop. I have the back of the saw mostly sealed up as well as the tilt slot in the front, so my dust collection works well enough to prevent dust build-up. Plus I'm not planning on moving the blade angle ever again on the saw. As long as my workaround keeps working, I'll be okay until I track down my next saw.

[Orlando Gonzalez]

I feel your pain and I know this is not going to help solve your issue. I once had a Ridgid contractor saw that wouldn't stay aligned even with the PALS system.. Got fed up with it, took it apart, threw it in the back of the SUV, took it to the dump, and promptly deposited it into one of the bins. Got a Craftsman hybrid and when that tanked got a Grizzly G0833P (now the G0899P) both with the cabinet mounted trunions. If I would have had 220v power then I would have gotten a full sized cabinet saw. If you can, get a full sized cabinet saw. Their parts are more robust than the hybrid ones and they stay aligned.

[Lee Schierer]

Lee, I discovered today that my Forrest Woodworker II has a dished shape on the steel face. I was attempting to use a triangular setup gauge to check the blade angle (against the steel, not against the carbide) and there's a significant gap in the middle part of the blade vs. the straight edge. I think this would render the Beall gauge unreliable as well.

For $70 from Rockler you can get one of these (LU82M) that will perform every bit as good as your Forrest blade, the a Beall Gauge will work.
62799-01-1000.jpg

[Frank Pratt]

The Freud Premier Fusion is also an excellent combination blade that will equal the Forrest in cut quality but at a much lower cost.

[Curt Harms]

Lee, I discovered today that my Forrest Woodworker II has a dished shape on the steel face. I was attempting to use a triangular setup gauge to check the blade angle (against the steel, not against the carbide) and there's a significant gap in the middle part of the blade vs. the straight edge. I think this would render theBeall gauge unreliable as well.

I believe I'd check Forrest's vaunted customer service. Table saw blades shouldn't be dished. Re a new saw either a 'hybrid' or cabinet saw would be a worthwhile upgrade. If you go hybrid, I'd make sure the trunnions mount to the cabinet, not the table. Cabinet mounted mechanisms are IMO easier to adjust and I think beefier and more likely to maintain alignment.