Tramming a Bridgeport Mill

[Old Megawatts]

I posted this previously but perhaps on the wrong place.

I have a question for someone who has more experience than I.
It is pretty simple to sweep the table in the x axis. However when sweeping the y axis, if you have to move the head, it isn't a simple + and - reading on the indicator as the center of rotation of the head is offset from the table. I have been toying with the idea of purchasing a cylinderetical square for this purpose. Then one could just mount the indicator in the spindle and extend the ram down the side of the square. Any comments??

OM

[tobyaxis]

This has always been a PITA for me as well. What I have done in the past to set the Head square to the table is to make a 12 by 12 by 2 inch thick Jig Plate. (This stays in my tool box) Then milled flat on both sides and an 11" Diameter 1/16 deep sweep area on the other. This of coarse was done on a CNC Mill which I hope you have.

Personally, once I set a Head it never gets moved again LOL. I buy or make precision angle sets to change the angle of the cut.