Hello,
Tramming procedure, after working with jt this past week on an issue I was having with tram and what I thought was a sag issue on the 5th column end. I had installed a dro and pressurized strut to help keep tram when moving the bridge. Now I don't need it. I had tramed the front to back with a shim under the lift plate before but didn't think about the other till now. So I hope this will help someone.
Place an indacol or and dial indicator on swing arm mounted on the quill or in a collet. Lower the Bridge so that the indicator is 0.100 down in a spot and leave the 5th and lift lock unlocked and Center the table under the quill and allow the swing of the indicator to reach the edge of the table across the x axis because the further out you go the more accurate the tram. But during all of the measurements make sure you are 180 degrees from each point on each axis to give the best acuracy. The goal is so that the measurment is the same at all points, within .0005 or less is the best. You may wish to start with the y axis first and once you have that it may be just a matter of moving the shims along the x axis under the lift plate. To be able to get the shims under the lift plate you lock the 5th end, loosen the 4 bolts securing the lift plate to the headstock and if you need to place them front by the chuck you drop the Bridge and it causes the plate to lift by the chuck, if you need to get shims by the pully end you raise the bridge, by locking just the 5th end moving the Bridge causes a leverage action lifting the lift plate. Position of shims by the chuck end causes the Bridge to raise on the 5th end. So for me I got tram on the y axis 1st and moved the shims to help raise the 5th end till I got close and if needed added the same shim size to both sides to help get the x axis in tram. For me I added .022 on the motor side at the very front by chuck and .003 on the operator side back by the mounting bolt towards the chuck. Moving the shim of even the same size along the x axis under the lift plate can have a large effect on the tram in the x axis. When done it took about 3 hrs to get within .0005 on all axis. Please note tram needs to be done with the bridge unlocked on both sides so when you use the a axis for machining it stays in tram. If you are going to lock the Bridge to just use the quill to keep tram you first lock the lift end and then the 5th end. Make sure the 5th column is squared to the Bridge so when you lock it it doesn't effect the tram.
JT helped me with some of this info and asked me to pass my experience along