G0704 Setup - Tramming/Squaring to Table Issue

[LorenB667]

As I look at the three photos, the low spot is in the middle @ -.0027", At the far end, you are @ +.0009 and at the near end, you are a+.0028".

A parallel is not necessarily a flat surface on its wide face nor is it necessarily uniform thickness between the wide faces. It is meant to be uniform in thickness between the two narrow faces with a face surface on each.

So, taking the parallels aren't necessarily parallel along their wide sides in to account, I just did it with 1-2-3 blocks to check it that way.

 

[RJSakowski]

OK. You're on the right track but not quite there yet. If the table has a dished out area in the center due to wear, as many older mills do, the two 1/2/3 blocks aren't necessarily coplanar. This shows in the .0009" difference over approximately 1.5" for the rear block vs. .0004" difference over approximately 2.5" for the front block. A parallel could be used instead by setting it vertically and clamping to a 1/2/3 block to support it. That is probably your closest object to a straight edge and it will be closest to a surface parallel to the table surface.

To complicate matters, I found my the table on my new Tormach to lift as I moved it to the left due to the overhanging weight past the supporting ways. The amount of lift increased along its travel but not in a linear fashion. The upshot of it was that even with my best effort, attempting to cut a flat surface wouldn't succeed. I was able to reduce the lift significantly by tightening the gibs Here is the plot of table elevation vs. x and y position. The 0,0 position (home) is with the table to the far right and out. The dashes lines are before gib adjustment and the solid lines are after. As you can see, I am within about .001" over 14" in x and .0007" over 6" in y.

 

[LorenB667]

@RJSakowski

I did as you suggested. The pictures below are my results. What do you think?