Hi GM&M & Dourk,
I have actually noticed this casting memory even on new machines that I have installed coming from Japan. Usually sitting over night is enough for the new machines, this seemed to occur more often on verticals then horizontals. I believe its because horizontals usually have thicker and larger castings I have seen fewer problems on new horizontal machines and more with machines that have been in production for long periods of time. Whether it’s because of wearing turcite, casting memory, or other stress factors that is unknown. But this will help you either way to square up the machine if it is a casting memory problem or some minor wear in the turcite. Most cases that I recall I have seen castings settle into .002-.005/foot.

You are right in extreme cases as this may be for this machine it could be worn turcite. Which I should have mentioned as well. In this case the part that rides on the top of the way or the capture plate that holds the Z-axis to the ways, which could cause the head to tilt forward could be the problem. It’s also possible that there is wear on the box ways for X and Y axis which may also cause the table to tilt. If you ran out of room to turn in the gibs on Z-axis then there is definitely some wear. This wear may also be a sign of a lubrication problem. Check that there is oil dripping out of the bottom side on top of the ways.

Beyond a turcite problem there is nothing else that could cause the head to tilt that far forward. I will admit 8 or 9 thousands is a bit excessive. The only other thing it could be is either the casting has the memory from over time or someone took a cut on the table. Also if the machine is anchored some people do not know how to level a machine and will actually distort the casting into shapes it was not meant to be in. Which I have witnessed once on a big used machine installation, that a maintenance guy decided to do one day to try to get ahead. Needless to say we had to redo it and leave it sit over the weekend before we could continue. Turcite is cheap however the labor involved is a lot and a quick fix by no means.

So first check that all the ways are getting lube and might not be a bad idea to mount an indicator on the spindle head and place it across the table and move in Y direction to get an idea if it’s possible that the turcite is worn under the table. First place a precision level on the table and run the table in 6 positions and get that absolutely perfect before running your indicator checks. Do not worry too much about the tram at this point. Once there is no twist in any X or Y axis movement or is even on both sides. Then run your indicators. This should tell you if the table top is parallel with the Y axis ways.



Kind of hard to explain in writing but hope some of this information helps

Petro