Trunnion won't stay aligned - contractor saw

[Marti Kassman]

I've aligned it 3x and after a couple cuts the rear of the blade moves toward the left miter slot about 1/32". I'm afraid to tighten the 4 bolts anymore or they may snap off. Could something else be causing the misalignment?

[glenn bradley]

Creeping with contractor saws has been traced to a cracked trunnion casting in my past. I would get it aligned, make a few cuts, scratch my head and re-align and have it go out again, A crack in the trunnion leg would open, I would align for that and it would open some more. Finally opened enough for me to notice. I'll hope it is not that for you. You can replace the washer and lock washer on each bolt to be sure they haven't been deformed or lost their spring. If you can confirm the rear is what is moving, PALs would lock the rear in place. This will not help if the wandering is on a front bolt.

[Marti Kassman]

Thanks. I'll make a pair and see if it helps

[Lee Schierer]

Knowing which saw you have would help.

On my Craftsman saw, I struggled to get the alignment set where I wanted it. I figured out that when I tightened the bolts, the lock washers were pulling the trunnions right back where they started from. I cured the problem by rotating the lock washers so the teeth were not in the grooves they had made in the cast iron.

[Peter Kuhlman]

I had an older “Crapsman” contractor saw and had the same issues. Used the Pals and it helped somewhat. The problem got much worse if I did any type of bevel cuts as the weight of the motor hanging off the back of the thin trunnions would alter the blade to fence alignment. Finally after taking an extremely painful kickback to the chest I got rid of the saw. No way to fix the weak flexible trunnions.
As Lee says, knowing what brand and model of saw you have would allow specific ideas and responses to your question.

[Thomas McCurnin]

I had the same issue with my Sears and Delta contractor's saws. I finally gave up, they won. I bought a cabinet saw.

[lowell holmes]

My 1970 Delta Contractor 2000 Saw has been bullet proof. I converted it to 240 volt by changing the switch to 240 volt and changing the jumpers in the motor. I installed a 240 volt double pole switch in a house hold switch box and use a 240 volt extension cord.

[Mike Cutler]

My Jet Contractor saw used to give me fits also. It had four bolts to lock the mechanism in place.
The two in the rear were easy to get at. I installed the pals there. The one at the front right of the saw, as accessed from the rear, was not easy to get to. The front left bolt, as accessed from the rear, was impossible to get at. Hopefully your saw has easier access.
I finally gave up and removed the entire table and mechanism from the enclosure. I then set it up on a makeshift bench, two saw horses, to be able to access all four of the bolts. I finally got it aligned, all the bolts tightened, and backed up that front left with two pieces of 3/8" tool stock to lock it in place forever.
It's probably been twenty years since I did that, and everything is still set where I left it.
I think I also changed the fastners and washers, but i don't remember exactly why. Most likely for the reason that Lee pointed out.
It's time consuming to do it this way, but it works.

[Marti Kassman]

I made a couple PALS with 1/4" angle iron, studs half 8mm and half 5/16, we'll see how long they stay locked.

It's a 40 year old Taiwan saw but was built quite heavy duty.

I cut out some sheet metal on the front to access the bolts, to avoid crawling inside with 2 long extensions on the ratchet.

[john bateman]

Even if you get it aligned well at 0 degrees bevel, you may find it is incorrect when the blade is tilted.