Pm932m-y Tram Off .003 Over 4"-y Gib Adjustment?

I may be over-simplifying things, but how about forgetting the lift and use a couple of wooden blocks on the table and a short chunk of 2x4. Loosen the bolts a small amount and pry the front up--insert shims--lower back into position and tighten & check--rinse & repeat till done. If the rear needs shimmed, you won't even need to lever it--should tilt forward with the weight alone. It would appear that the bolts shouldn't need to be loosened much more than 1/2 -1 turn to insert shims. I am going to need to do mine soon, also.

Jerry in Delaware
 
Muskt said:
I may be over-simplifying things, but how about forgetting the lift and use a couple of wooden blocks on the table and a short chunk of 2x4. Loosen the bolts a small amount and pry the front up--insert shims--lower back into position and tighten & check--rinse & repeat till done. If the rear needs shimmed, you won't even need to lever it--should tilt forward with the weight alone. It would appear that the bolts shouldn't need to be loosened much more than 1/2 -1 turn to insert shims. I am going to need to do mine soon, also.

Jerry in Delaware
Click to expand...

A couple of weeks ago I shimmed my column using this process except for one slight deviation. Instead of prying the head with a 2x4 I engaged the quill downfeed knob on the right side of the mill head and used the downfeed handle to raise the front of the column. Same result, different approach.

Tom S
 
Thanks guys. So you are saying the lowering the quill onto a block of wood will create enough force to push the column up? No risk of damaging the spindle doing that? Again, novice, but it seems that's a lot of weight to put directly on the spindle.
 
You are much less than a 1/10 of the design static load of a pair of angular contact bearings of that size.

Of bigger concern is making sure you don't lose control of the column/head while you are doing this. I am guess it is at least 400+ lbs, so the key is LOOSEN, not removing the column-base bolts while you are doing this.
 
Same machine or smaller than the pm932? Seems like this would be ok for a smaller machine but the pm932 head is pretty heavy and my concern would be what effect this would have on the spin
TomS said:
A couple of weeks ago I shimmed my column using this process except for one slight deviation. Instead of prying the head with a 2x4 I engaged the quill downfeed knob on the right side of the mill head and used the downfeed handle to raise the front of the column. Same result, different approach.

Tom S
Click to expand...
 
Ok guys I think I'm lost in how to team with my spindle square. Before I mess with the column shimming, im starting over making sure I've done everything else before resorting to shimming.

In x, I am dead perfect when looking at the spindle square as I face the mill. I rotated the spindle square to face the column, and now I'm off .003. All I did was rotate 180 degrees. Help.

Does anyone have a good link on how to properly team using a spindle square? Thanks for the help.
 
That is because your spindle square isn't square.

How did you zero the dials on it? That has to be done before use.

Traditionally, you "sweep" the surface with one DTI , and you zero it at +X, and rotate it to -X, and then tram the mill until +X and -X are the same.

The spindle square means you don't have to sweep the surface while doing the tramming, but you do have to zero it before use by sweeping it 180 degrees.
 
Last edited:
I squared it on a brand new calibrated inspection plate prior to use. I'm taking it out and doing it again now but I don't believe that's the issue.
tmarks11 said:
That is because your spindle square isn't square.

How did you zero the dials on it? That has to be done before use.

Traditionally, you "sweep" the surface with one DTI , and you zero it at +X, and rotate it to -X, and then tram the mill until +X and -X are the same.

The spindle square means you don't have to sweep the surface while doing the tramming, but you do have to zero it before use by sweeping it 180 degrees.
Click to expand...
 
Are you sure you need a hoist? I was able to tilt mine enough to slip shims under the front of the column by pushing with my left hand and using my right to insert the shim. Not that hard just be sure you only loosen the bolts, not remove them. I backed the front bolts off a lot and the rear only enough to allow the head to tilt. You aren't lifting the head, just tilting so shouldn't require a ton of force.
 
Squaring it on an inspection plate won't work. Regardless of what the instructions claim.

Put it in the spindle, put a gage block at the +Y extent. Zero one indicator on the gage block, spin 180 degrees, and zero the second gage block. That takes out any errors (such as slight alignment error in the spindle square shank).

See below at time 1:00


They use a magnet, but the gage block works just as well. You can also go right against the table, but then you really need to hold both DTI up while rotating, which is a PIA.
 
You must log in or register to reply here.
Back
Top