Question about TS top shims

[Geoffrey Keating]

Hello all,

I read the board quite a bit but post rarely. Usually when I have a problem;). Right now I'm having a problem with the shims under the top of my TS top and any suggestions would be greatly appreciated. Here's the situation:

I recently moved a PM 2000, and to do so I removed the top. Unfortunately, when I did the shims fell off. (I'm kicking myself for not easing up each corner to grab them.) As I was outside in the grass there is a chance that I haven't been able to find them all (although I spent a good hour on my hands and knees digging around). And I'm not sure of the position of the four that I did find.

As is sits now, when you put the top back on with no shims it's flat across all the edges, and one direction diagonally, but in the other direction diagonally one or possibly both corners sag a bit.

I started using pieces of feeler gauge to try and shim it up to get the sagging corners up. It seems that as soon as you get it flat that way, the other corners started to sag. After messing with it for about six hours, trying every combination I could think of I'm feeling pretty frustrated.

If anyone has any suggestions that would be great.

Thanks,
Geoff

[Matt Ocel]

Ouch!

If you think there is more shims in the grass - try a big magnet.

As far as re-aligning the top, I don't know.

I had a tough time just shimming my PM on the floor.

Good Luck!

[Jamie Buxton]

The shims may be adjusting more than the table flatness. They can also be aligning the blade to the miter slot when the blade is beveled over 45 degrees. Here's a thread -- http://www.sawmillcreek.org/showthread.php?t=15546

[Jim Becker]

What Jamie said. They are somewhat critical if you do bevel work. You may want to get advise from the manufacturer about exactly how to do the necessary re-alignment and shimming to bring it back to factory spec.

[Geoffrey Keating]

Gentlemen,

Thanks so much for the responses. The magnet is a great idea (didn't think of that).

Jamie, I read your linked thread (excellent info). Where did you buy your shim(s) by the way?

Jim, thanks. I'll start making some calls in the morning (my hope was to take care of it if possible this weekend, but that may not work; it seems whenever I screw something up it happens on a Friday afternoon at 5:01).

[James Suzda]

First thing I'd do is to make sure your base is level and true, and make sure all the corners are even with each other. Otherwise you will use a lot of washers just trying to get the saw cabinet in alignment.

If you need some instructions on how to align your saw top, Grizzly explains the procedure very well if you check out the manual from one of their saws online.

I've used aluminum can material for thin shims when leveling my saw top. (I know I will probably receive a bunch of heat about aluminum will flatten out.) Otherwise all the rest of the shims are plain old washers of various thickness.

[Geoffrey Keating]

Jim, thanks for pointing me to the Grizzly manual. It has about ten times the info that the PM2000 manual has.

[Jamie Buxton]

Jamie, I read your linked thread (excellent info). Where did you buy your shim(s) by the way?

There's lots of shim material readily at hand. For example, the sheet metal in beer or soda cans. For another example, business cards. For a third example, expired credit cards or the fake credit cards which come in the mail. I generally use the biz cards or credit cards.

[Eddie Darby]

http://www.leevalley.com/wood/page.aspx?c=2&p=40946&cat=1,43456,43407

Brass Shim Stock.

[Ted Torres]

http://www.leevalley.com/wood/page.aspx?c=2&p=40946&cat=1,43456,43407

Brass Shim Stock.


Thanks for the heads up Eddie, got some on order!:)

Ted

[Wade Lippman]

One of us is confused about shimming. I hope it is you.:)
The table is flat or it isn't; cast iron is very rigid and shimming isn't going to change that. All shimming does is change the position of the table with respect to the blade.

[glenn bradley]

One of us is confused about shimming. I hope it is you.:)
The table is flat or it isn't; cast iron is very rigid and shimming isn't going to change that. All shimming does is change the position of the table with respect to the blade.

Actually CI is fairly easy to manipulate. If you were to loosen some of the bolts on one extension wing and lean lightly on the loose end, it will flex a surprising amount. Use of shims is pretty standard on cabinet saws.

[Geoffrey Keating]

Yeah, the top is pretty flexible. When I set it on my bench it gets a lot flatter than when it's on the saw.

I'm still not having any luck, as it seems to crown in the center. Once I get it pretty flat diagonally in one direction, the other direction still sags in the corners and vice versa. Maybe I just haven't found the right combination.

Any further advice is still greatly appreciated and thanks to those who have responded already.

[Tom Veatch]

.... All shimming does is change the position of the table with respect to the blade.

It actually performs two functions. The top of the saw's cabinet is probably not a true plane - rarely do 4 independent points all lie on the same plane. One of the points will be below the plane defined by the other three. Adding shims at the low attachment point will bring that point up to the same plane defined by the other three attachment points. And it only requires shims at one of the attachments.

Once that plane is established, it becomes the reference plane from which shimming at two attachment points (front or back) is done to bring the plane of the top into parallelism with the trunnion tilt axis.

[Geoffrey Keating]

Thanks to all for the advice, etc...

I finally got it within factory tolerances. Unfortunately, I don't have any advice for fixing the problem other than don't take your top off or if you do make sure that you pay better attention to the shims (some were stuck to the underside with grease when I pulled off the top, then as soon as I cleared the base they let go and dropped into the grass; it was only then that I realized there had been more underneath).

In terms of conceptualizing it, Tom's advice is best. The only problem was that bringing the one point into the plane of the other three caused the top to flex, and because (I suspect) of the nature of the reinforcement on the underside of the table as well as the oval hole for the blade, the top didn't flex uniformly. As such, the one of the other points would move out of the newly created plane.

A royal pain in the you know what.

Anyway, thanks again.