PM-66 alignment problem

[John, in MN]

Today is my annual fix-up and tool checkout day. When going over the PM-66 TS, I checked blade to miter slot alignment which looked good but then tilted the blade 45 and checked again. Off about .008 from front to back of blade. Never checked this before because of not having a dial indicator at the time. Seems to be something that could be tweaked a little. Is this corrected by shimming the saw top front to back? Couldn't find anything dicussing this DAGS. Thank's for any info.

-- John, in Minnesota

[Pounds on Wood]

Yes. It's a procedure that should always be done as part of a TS tune-up, but seldom is.

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[Pounds on Wood]

Oh in addition, 8 thou isn't too bad. My last two saws were off a sight more than that.

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[Upscale]

Could something like this be fixed by the use of blade stabilizers? I'm wondering of the little bit of stress caused by the tightening of the arbour nut might create this type of slight mis-alignment?

[Charlie Self]

John in MN asks:

Yeah, but...this small a misalignment just about comes under the old, "If it ain't broke" maxim. It's probably not worth messing with unless you're seeing problems with cuts.

Charlie Self "Property is not the sacred right. When a rich man becomes poor it is a misfortune, it is not a moral evil. When a poor man becomes destitute, it is a moral evil, teeming with consequences and injurious to society and morality." Lord Acton

[Tom Veatch]

That could indicate that the tilt axis is not parallel to the plane of the top. But, I'd advise leaving it alone unless you are noticing a problem with the cuts made with a tilted blade.

My reason for recommending this is when you start shimming, if you introduce a left/right tilt in the table top, then the axis of rotation used to raise and lower the blade will not be parallel to the table top and the blade alignment with no tilt will vary with depth of cut.

Secondly, the measurement you made can be very difficult to make and could have a large margin of error. Very small variations in the height on the blade at which the measurement is taken can very easily account for the .008 variation you are seeing.

If it ain't broke (screwing up your cuts), don't try to fix it.

Tom Veatch Wichita, KS USA

[Anonymous]

One of the magazines did an article on this a few years back .. .. the axis of tilt is not parallel to the table top. Slight shimming of either the front or rear table mounts will bring this into alignment. If it's not burning or causing kickbacks and the cut quality of bevel rips is acceptable, .008" really is not too bad.

[John, in MN]

I checked again just to be sure by measuring from the other side of the blade. No problem. Looks like a small dip in the ole cast iron top is what I was measuring the first time. Everything else looks good so the PM-66 alignment is done for about another year. I'm really impressed how well these saws hold their alignment. 20 some years old ( I'm guessing ) and it's still running great. Sorry for the false alarm and thanks for the replies.

-- John, in Minnesota

[Tom Veatch]

left/right tilt in the table top, then the axis of

the blade alignment with no tilt will vary with

Major brain fart, please ignore.

Left to right tilt on the table is easily accommodated with adjustment of the 45/90 degree arbor tilt stops. The effect described, alignment changes with changes in depth of cut, indicates the depth of cut axis is not parallel with the arbor rotation axis. Depending on the design of the trunnion assembly, there may be adjustment provisions, but far more likely this would be either a defect in the machining of the trunnion or warpage in the trunnion after machining - a defective trunnion in either case.

However, my recommendation remains the same. If it ain't broke, don't fix it..

Tom Veatch Wichita, KS USA

[Pounds on Wood]

It could I suppose, but proper technique should eliminate that.

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[bridger]

I've been wondering about this one also.

anybody have a link to an advanced cabinet saw setup page?

[CW]

No. If your blade is parallel in the vertical position but not parallel when tilted, it means that the pivot is not parallel to the top. Move the pivot or move the top, whichever is possible. Unless I could see that there was a problem during actual use, I wouldn't worry about it. Dial indicators often cause one to worry about insignificant things.