Table Saw Blade height lock knob problem

[Michael Heffernan]

I've got an issue that I need some advice on.
I have a Steel City 3Hp (Model 35630) right tilt table saw. I cannot get the blade height adjustment wheel to lock down tight. Every time I set the height and screw the lock knob, the adjustment wheel moves a little, even though I hold it in place as I torque the lock knob. And even with the lock knob tightened as much as I can get it, the height adjustment wheel can still be turned, knocking the blade height off its mark. I removed the lock knob and it is not worn at the point, so I am not sure what is going on. It's frustrating when I am trying to set an accurate blade height for dadoes and tenons.
I thought I'd try here before I give Steel City a call. Anyone have this issue with their table saw and have a solution? Appreciate any help or advice.

[glenn bradley]

The wheels on my hybrid are smaller in diameter than your saw's. Still even when locked down, I can still the wheel if I try. The wheel does not move while I am operating the saw. This is just a friction action, not a toothed locking sort of mechanism. Unless the height is moving during use once tightened down, I would say this is normal. If once tightened down the wheel can be moved easily with one finger or the blade height is actually changing on you, I would give them a call.

[Tim Wagner]

do you have a book with a breakdown on how it is assembled and how it works? maybe there might be something at the bottom of the hole keeping it from screwing all the way in. that would be my guess or posibly the shaft on the lock knob may not be long enough? or threads damaged? if the blade won't sit still while in use I also would call CS.

Tim.

[Johnny Pearce]

I also think that it maybe bottoming out. Can you remove the knob and put a washer [nylon if you can find one to fit] and see if it makes a difference?
John

[Kevin Groenke]

From a quick look at the manual for that saw
http://www.steelcitytoolworks.com/pr...630_manual.pdf
it appears that the locking mechanism is similar to that of a unisaw. The angled point of the locking knob shaft pushes a similarly angled "button" (PT# OR70720 SHAFT LOCK PIN) against the casting outside of the elevation adjustment shaft. Those buttons could be damaged/deformed/worn or the casting itself could be damaged. If I remember correctly, on Unisaws, the entire shaft has to be at least loosened (if not removed) to change/service the pins. Shining a light and peering down the shaft may clear things up a bit. Ultimately, this is simply not a particularly precise or robust locking mechanism so you may just have to learn to live with it.

[Howard Acheson]

The rule has always been to set the height of the blade by cranking it up, never down. All worm gears have play or "lash". By cranking up, gravity keeps the lash out of the adjustment and locking the height will prevent any self induced lowering of the blade.

[Doug Shepard]

The rule has always been to set the height of the blade by cranking it up, never down. ...

Yup. My PM66 will drop if I get lazy and just lower it then lock. If cranked up then locked it stays put.

[Michael Heffernan]

Thanks everyone for all your advise on correcting the lock knob problem. I haven't gotten to investigating the issue, but I'll try some of your fixes and see if anything works.