Any helpful hints for tramming?

[BEDFORD]

Well I machined my own fixture to hold two dial indicators so I can do both axis at once. I have been having a heck of a time getting it all squared. What are you guys using for shims? I have been using hand hammered brass as it's all I have at the moment. I've noticed that you can have it dead on and move from the table to the top of the travel (or my squares in this case) and it still looks good. Then you run the travel back down and suddenly it's off (I think this can be attributed to my one square flexing which I noticed at the end of the work day). Even me standing on the very sturdy MDF cabinet it is solidly bolted to is causing discrepancies.

I guess the moral is to consider everything that could possibly affect the measuring process when tramming a mill.
James

[KEYTEEM]

The industrial hobbies site has a segment on tramming ,,
I did one "side" at a time , with a "known good " vise jaw fixed to
the table and one indicator mounted in the spindle. i bought shim stock
from a local hadware store from .001 too .005 . it was like 4 bucks a
bag.
i think doing one side at a time would be less agrivating,, GOOD LUCK

[phil burman]

Don't be over ambitious with respect to ultimate accuracy. It can be an unnecessary exercise in futility. What are you aiming for? As you have seen even when you load the bench the machine deflects. The mill will also deflect when under load from the cutting tool. So achieving the last tenth with a DTI and no load is a pointless exercise. Some would argue that a slight “toe in” so to speak will actually give a more accurate result when under load.

Are you locking the Z axis each time you take a measurement. Is there any radial play in the spindle, the possibilities are almost endless. You need to give a detailed description of your procedure if you hope for somebody to spot the problem.

It's not a $50,000 Deckel. Do lots of measurments, learn it's degree of inaccuracy, then learn to live with it. Next step would be to do some lapping, can't say that I'm happy to recommend this but it seems to have the possibility to make a bad machine not so bad.

Regards
Phil

Originally Posted by BEDFORD Well I machined my own fixture to hold two dial indicators so I can do both axis at once. I have been having a heck of a time getting it all squared. What are you guys using for shims? I have been using hand hammered brass as it's all I have at the moment. I've noticed that you can have it dead on and move from the table to the top of the travel (or my squares in this case) and it still looks good. Then you run the travel back down and suddenly it's off (I think this can be attributed to my one square flexing which I noticed at the end of the work day). Even me standing on the very sturdy MDF cabinet it is solidly bolted to is causing discrepancies. I guess the moral is to consider everything that could possibly affect the measuring process when tramming a mill. James

[BEDFORD]

Well I finally got the mill squared to a point where I am happy. My problem was every time I'd add a shim I was twisting the tower out of alignment. I'd end up shifting it sideways so my measurements would be off. I understand that no machine, especially not this one, will be dead on. I have been loading the spindle and checking deflection and honestly considering the amount of deflection I think that being square at all is enough.
Thanks
James