October 7, 2013

Tramming the mill spindle square 40939

The tramming of the milling machine headMINDLESS BORING: is an indicator of the alignment of the spindle center line or "squareness" of its perpendicularity to the x y table axis of travel. Here i tram the head of a 40939 6x26 knee mill. The head tram adjustment procedure is nearly the same for all milling machines, although the locking bolt may differ in location. The method of tramming the spindle alignment shown here is referred to as sweeping the head and uses a dial test
indicator to sweep over the mill table through an arc from the spindle centerline and covers a large area of milling surface. The longer and more ridged the the connection of the dial indicator to the spindle, the more accurate the measurement of tram you will have to make the milling head adjustment. The level of accuracy you tram the milling machine head to is determined by your work requirements, although a poorly trammed milling head will immediately show up during a face milling operation in poor surface finish.

A milling spindle that is out of tram cant cut squares. Errors in the tramming of the spindle in the x and y planes of the mill will become more apparent with an increase depth of z axis cuts included in the part, as in deep drill holes non square angles and tapered pockets. It is best to use a machine level to level the machine before
tramming any axis as frame twist can affect these measurements. I use a starrett 98 machinists level and a interapid .0005 dial test indicator to tram the mill. Watch this short video of tramming a milling head and gain confidence when machining that any errors in parts wont be because your spindle is out of tram. = SHARE ROCKNTV1