Quote Originally Posted by mocha View Post
does the cast iron assembly not flex the unsupported round rail at all??
I have not really tried it out yet together with the new tool post. And it is true that were I starting again I would use 25mm diameter rail and not 16mm as I did, I am sure it must a little. The table will be locked solid when cutting patterns. If you look carefully you will see that I have placed a screw based locking clamp between the two linear bearings on each side. The bearings and rail are just acting as a rapid positioning mechanism for the table. My reason for going with a heavy tool post is to dampen the vibrations I was experiencing. It may be that my real problem is not with the tool post but with flexing of the rail. I will not know until I have run a few test cuts. If there is still a problem then I will consider separating the headstock from the tool post rail and re-engineer tool side using 25mm rail as a minimum. However compared to standard milling, cutting OT patterns is a relatively gentle operation. The max cut you would take is 1mm and more often much much smaller than that. Also the work rotates very slowly up to about 5 rpm max and often at 0.5 rev per minute on finishing / polishing cuts which can be 0.01mm at max.

Alan