Thread: ST-254 style Table Saw Blade slop in blade lowering and raising mechanism

Thats a lot of play. Or backlash. As it is only on the down adjustment, to set the bade height go lower than your setting and adjust in the upward direction.
It looks like there are two circlips holding the worm drive / sleeve in place and preventing it from moving back and forth. Check that these are both still there. That amount of backlash looks like something is moving that shouldn't.

It's pretty hard to see how it all fits together from that exploded view. Is the hole in the Lock Nail Bush (#95) centred or eccentric? If it's eccentric that would be my best guess as the part that allows the meshing of the worm gear to be adjusted. There is usually a bit of slop (backlash) in these mechanisms, but yours does seem particularly bad. On my contractor saw after lowering the blade I turn the handle clockwise until I can feel the rise engaging, then lock the blade position in place. I have adjusted the saw to minimise backlash and can't say that I've ever found it a problem. You can get a schematic that allows magnification here - https://images.machineryhouse.co.nz/...w%20Manual.pdf - that may help.

I see now that the schematic I've linked to is slightly different to the one you've pictured.

Originally Posted by aldav

It's pretty hard to see how it all fits together from that exploded view.

Too true!

Here's a pic from the (wrong side) from the Axminster manual. The parts numbered in this picture are

1- The worm gear wheel
2- The geared shaft
3- Bolts to attach Adjusting Frame to chassis piece. The Worm Wheel shaft (part 122) is attached to this chassis piece as well.

doorSide.jpg

There doesn't seem to be much slack in the holes the bolts go through to allow the geared shaft fixed in the adjusting frame to be lifted higher so it meshes more tightly with the worm gear wheel. This would seem a likely place to take out some slop.

I guess another possibility is the piece 116 which locates the worm wheel shaft to the chassis piece might have some slop in the holes allowing some adjustment there as well.

If this is related to Leda saw mentioned elsewhere, what has their response be?

not expecting much from them.

It certainly looks different in the flesh. The only possibilities I can see for adjustment there are:
1. At the top on the geared wheel (circled in red) - if there is an eccentric bush between the mounting points that the geared wheel runs on.
2. At the worm gear mounting (oval shape in red) - if the fixtures that the worm gear mounts on at either end has some kind of eccentric adjustment.
I would think that option 2 is less likely to be the case.

If neither of those points provide a solution I'm stumped.

Edit: Another look. Part #116 in your drawing that the geared wheel is mounted on looks like it is mounted by a bolt that is off centre to the wheel (the bolt circled in the pic. I posted). If this is correct undoing that bolt should allow the adjustment you're looking for.

The only point of adjustment for mating the worm drive is via movement at the elongated holes where the bolts at point 3 fix the brackets together.

I loosened these off and clamped the worm wheel and adjusting rod tightly together before tightening the securing bolts but there is still backlash between the teeth.

worm.jpg

Dropbox - VID_20220314_092948.mp4 - Simplify your life

Blade drop has been halved to about 6mm.

You've got me.

Originally Posted by aldav

You've got me.

I reckon the problem is the thread on the Adjusting rod is Acme and it's driving the Worm Wheel that is Whitworth(?) thread.