[zaebis]

I need to square my head to a table on Y axis as it is nodding and loosing 0.004" over 12" of Y travel. I hear that it is done with shimming where the column is bolted to a base. I identified such places but I am not certain on;

1. Shimming material. What can I use and what size. Can I use filler gauge?

2. SIze of the shim. Right now the column is flush bolted to a base. Once I place shims on one side (to eliminate column noding) it will effectively rest on a small shim and not have a full contact to a base. Will it not drastically undermine rigidity of a column?


thx

[packrat]

Before shimming the column, make sure there is no twist in the base of the machine. If all the mounting points of the are in one plane of reference, the base can be twisted or bowed. That will cause the column to tip or nod, compared to the table. Especially on bench top type machines. A plate of ~1/2" steel under the machine is a good idea for these small light duty mills.

[wizard]

I'm not sure I'm following here.

I need to square my head to a table on Y axis as it is nodding and loosing 0.004" over 12" of Y travel. I hear that it is done with shimming where the column is bolted to a base. I identified such places but I am not certain on;

You say your head is nodding but then you mention Y axis travel. You need to make sure you are measuring the right parameter here.

If the column is out you could shim it or scrap it in depending upon the amount of error. If it is real far off it may require machinng. Do none of these things until you are sure you are correcting the right error though.

1. Shimming material. What can I use and what size. Can I use filler gauge?

When shimming shim stock would be a good material to use

2. SIze of the shim. Right now the column is flush bolted to a base. Once I place shims on one side (to eliminate column noding) it will effectively rest on a small shim and not have a full contact to a base. Will it not drastically undermine rigidity of a column?


thx

It could impact things in a negative manner if you shim the column though I'm not sure the majority of users would notice the difference. The right approach would be to machine or scrap to correct geometry errors. This way you can maintain good contact between the mating surfaces. If not you want to be certain that the shim mates up with the contacting surfaces well.

However before you do anything verify you are correcting the right error. As stated above I'm not sure why you are tramming the Y axis to measure nod.