Bearing Race to Tram Mill?

[rwm]

Cheap

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This one is bigger but the price is stupid. Maybe negotiate?

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[Ulma Doctor]

4.25” OD????

 

[Illinoyance]

I just tram to the table. The vise is keyed to the table so I can just slide it out of the way. My setup is a 3/8" rod with a 90* bend and a Starrett back plunger indicator with the big mushroom contact tip. No need for brake discs, bearing races or the tramming gadget with two indicators. Keep it simple, Stupid.

 

[rwm]

The OD on the smaller one is close to 7". These are usually ground to within a tenth or so. I find it easier than traming to the table due to the T nut groves. I just center the bearing to the spindle and sweep with an indicator set to the radius. I think mine is 9" diameter.
I just thought someone might find these useful.
I think I got it from here originally:

Tramming a Bridgeport Mill by Tom Davis

In this PDF, Tom Davis shows how to tram a Bridgeport mill. Enjoy! Best, Nelson

www.hobby-machinist.com

 

[RJSakowski]

A proper tram aligns the the spindle axis perpendicular to the x and y ways of the mill. The assumption that the table surface is parallel to the ways and is a good surrogate for the ways isn't necessarily true. Wear or table lift due to play in the gibs can cause a non-parallel situation. It is easy enough to check. Mount a dial or test indicator in the spindle and sweep the the table surface in x and y directions. Deviations from flat and parallel can be mapped out.

If there is a deviation, the head can still be trammed, To do so, I mount an aluminum plate to the table and skim cut the path of the tram indicator using a small diameter end mill. The reason for the small diameter is that any error in the surface due to an out of tram condition is minimized. On a CNC mill, I just cut a circular path. On a non CNC mill, I would undercut the entire surface, leaving raised bosses at the four quadrants. (If there is sufficient height, future trams only require skimming the surface of the bosses.) I re-skim the tramming surface prior to each tram.