Unisaw worm gear height adjustment question

[Brandon Davis]

The saw blade on my Unisaw rests about 1/8 inch or so above the zero clearance blade insert at full down. So even when the blade is in the fully down position, it's sticking slightly above the top of the table surface.

Not good.

Can this be fixed by changing the front-to-rear position of the worm-gear?

Or should I be looking at something else?

TIA.

[Joe Kieve]

Not sure if it can be adjusted or not as I've never had that problem with my Unisaw. Have you measured the blade diameter? Maybe it's over 10".

[Brandon Davis]

Not sure if it can be adjusted or not as I've never had that problem with my Unisaw. Have you measured the blade diameter? Maybe it's over 10".

Thanks.

I have several blades (Freud's, Delta's, misc., even a Forrest). They're all the standard 10" size.

The saw was pretty obviously "tinkered with" at some point way before I got it. I'm slowly fixing the issues, and getting the blade lowered is the next one on my list.

That said, I'm not entirely sure this was a "problem" to whoever did it ...it may have been adjusted to this on "on purpose" ...it will, after all, cut thicker lumber than a standard 10" Uni'. I just don't need that "feature" lol.

[Mike Cutler]

Brandon

On most of the saws I've mucked about with, there is a bronze bushing, with a set screw, or key, on the lead screw shaft that operates the blade height mechanism. It is usually very close to the wheel, sometimes actually part of the wheel hub, Generally there is another bushing, or a mechanical limiter built into the shaft, that makes contact and blade motion stops, pr you get to the end of the trunnion gear.
If you haven't had issues previously, it seems that the bushing may have moved somehow, and or, the worm gear mechansm portion of the shaft is completing it's movement early. Hopefully you don't have any broken teeth.

One other cause can be sawdust. As the XO on the submarine use to say; "grease, dust and age" make a great adhesive. Hopefully a little light cleaning will be the only problem. Look at the worm gear area and the place where the trunnion lowers into position. There is usually some time of a stop.

[Lee Schierer]

I was going to suggest the same thing. Sawdust accumulation can limit the travel. I know on my Craftsman saw the saw dust on the blade tilt will build up and make getting to the 45 degree stop nearly impossible. When you lube your raise/lower worm and tilt mechanism, don't use grease as it will accumulate lots of sawdust. Use paste wax or a dry Teflon lube.

[glenn bradley]

I favor the gunk theory as well. Compacted sawdust can be incredibly durable ;-) If this was a used saw and this condition has always existed, it is possible that someone left the shims/washers out when the top was removed at some point during its life. If you are comfortable aligning tablesaws it should be no problem to pop the top and add washers/spacers to elevate it and then re-align. I'd look for saw dust first though ;-)

[Brandon Davis]

Thanks everyone, for your interest.

Gunk probably isn't the issue lol.

I went through the saw when I started getting it ready for use (and I "started" over a year ago), and cleaned pretty much everything you can reach with the top off (including the worm gears and most interior parts).

...and polished the exterior:

312637

It's been a garage queen since, as I haven't had time to go through it with a really fine tooth comb. (I just finished wiring it for 230V, as per a thread earlier this week.)

Here's a pix of the worm gears, and the raising shaft rear collar and hex nut:

312638 312639

You can see in the first pix that a) the worm gears are pretty clean, and b) the stop on the arbor bracket has gouged a path on the rear of the worm gear at some point? Maybe?

Per the following pix, my thought is whether the position of the raising shaft can be moved forward maybe an 1/8 of an inch by moving the rear collar and hex nut?

To my way of looking at it, that would push the worm gear forward, allowing the arbor bracket stop to move forward and down, and the saw blade to finally rest below the table top surface.

I just want to make sure I'm on the right path with this.

My saw is missing the correct pointer bracket, and I wondered if the jury rigged bent metal pointer that's there isn't part of the reason the raising shaft might be in the wrong place. (Notwithstanding that this might have been done "on purpose" to allow thicker wood to be cut by the previous owner.)

Here's a pix of the jury-rigged bracket:

312640

I just found a used [Delta OEM] indicator bracket for a reasonable price in a store in AZ this morning, so as soon as that gets here (along with some other small parts ...I'm replacing the stop plugs while I'm at this), I'll be tearing into it again at that point.

(This will be the 3rd ...no, the 4th ...time I've taken this apart. And I'll probably do some repainting of the interior this time, too.)

[Brandon Davis]

I favor the gunk theory as well. Compacted sawdust can be incredibly durable ;-) If this was a used saw and this condition has always existed, it is possible that someone left the shims/washers out when the top was removed at some point during its life. If you are comfortable aligning tablesaws it should be no problem to pop the top and add washers/spacers to elevate it and then re-align. I'd look for saw dust first though ;-)

Glenn? - Are there supposed to be some kind of shims/washers some place that affect the height of the table above the case?

...that could do it, too.

I didn't think of just raising the height of the table 1/8" or so LOL.

[glenn bradley]

Glenn? - Are there supposed to be some kind of shims/washers some place that affect the height of the table above the case?

...that could do it, too.

I didn't think of just raising the height of the table 1/8" or so LOL.

I've only been into about a half a dozen cab saws but, I have yet to come across one that didn't have at least one corner shimmed to set the blade to table alignment. On my hybrid saw I did a second adjustment due to changing some attached fixtures. As long as I was under there I added some thicker washers so as to get the blade well under the throat plate just as you describe. As it was, "out of the box", it only went below the table by a tiny fraction and you could still slice yourself even though the blade was fully retracted if a tooth happened to be at TDC. Funny how something like that will make you learn about these things ;-)) generally a bolt at each corner although some, like Saw Stop include a pivot pin at the front middle as well.

[Phil Thien]

Glenn? - Are there supposed to be some kind of shims/washers some place that affect the height of the table above the case?

...that could do it, too.

I didn't think of just raising the height of the table 1/8" or so LOL.

I've read about this issue on other Unisaws.

I believe Glenn is right, many of these saws had tables that were shimmed to make sure the blade stayed parallel to the miter slots when tilted.

I've also read accounts of people removing the tops and finding a spacer/shim under each corner. That may indicate they were more spacers, than shims.

I'd suggest heading over to owwm.org and posing this question there. Some of those guys are Unisaw fanatics.

Nice saw, BTW. You're doing a great job cleaning that beauty up!

[Brandon Davis]

I've only been into about a half a dozen cab saws but, I have yet to come across one that didn't have at least one corner shimmed to set the blade to table alignment. On my hybrid saw I did a second adjustment due to changing some attached fixtures. As long as I was under there I added some thicker washers so as to get the blade well under the throat plate just as you describe. As it was, "out of the box", it only went below the table by a tiny fraction and you could still slice yourself even though the blade was fully retracted if a tooth happened to be at TDC. Funny how something like that will make you learn about these things ;-)) generally a bolt at each corner although some, like Saw Stop include a pivot pin at the front middle as well.

Thank you.

...I've been making this way too complicated.

As soon as the additional parts come in, and I've got the top off, I'll add a thick washer/spacer at each corner when I put it back together.

...oh, I'll still check everything this time (I no longer trust that the previous owner reassembled this as I would have).

By adding spacers as you suggest, at least I'll know when it goes back together the blade will be below the surface of the insert.

Cheers!

[Brandon Davis]

I've read about this issue on other Unisaws.

I believe Glenn is right, many of these saws had tables that were shimmed to make sure the blade stayed parallel to the miter slots when tilted.

I've also read accounts of people removing the tops and finding a spacer/shim under each corner. That may indicate they were more spacers, than shims.

I'd suggest heading over to owwm.org and posing this question there. Some of those guys are Unisaw fanatics.

Nice saw, BTW. You're doing a great job cleaning that beauty up!

Thanks Pete.

I'm pretty fastidious about my tools.

After 25 years, my wife no longer looks askance when I bring home some rusty derelict (that I picked up for pennies on the dollar: I'm frugal, too lol), because she's assured it will be made presentable when I'm done.

...I think I'll take that suggestion about OWWM, too.

[Brandon Davis]

Followup and solution -

I received help with solving this problem over at OWWM, and I wrote up a 'how-to adjust the blade full down position' for anyone else facing the issue in the thread over there. (PM me for the link...not allowed to post links to other forums here on SMC)

...several people at OWWM suggested you could adjust the blade down position via the rear hex nut and locking collar which affect the overall fore-and-after lateral position of the raising shaft.

...sorry about originally including the link. I didn't realize that wasn't permissible at SMC.

[glenn bradley]

Excellent news. Thanks for the link also ;-)