Uni-Vertical tram problem

[blockmanjohn]

Hi, I have a Uni-Vertical bench top mill that has the Bridgeport type H head on it. While using a fly cutter going in the y axis direction I noticed that as the back of the cutter came over the work it was cutting deeper. I know that this means that the table is out of tram in the y direction. Sure enough, the table is about .004 lower in the front than the back.

The problem is that I can find no way of adjusting this. The head swivels in the x direction, but there is no evident way of adjusting the "nod".

I am hoping that some one is familiar with this machine and can help me get it in tram. Any and all suggestions will be greatly appreciated. Thanks, John.

 

[DJP]

I assume that some strategically placed shims should fix the problem enough to make it usable. I have a similar vintage Burke Mill and I don't expect fine tolerances from it.

 

[blockmanjohn]

As an option, I was wondering if a new, similar sized import mill would have better accuracy. I have never used an import mill so I have no idea how well they function. If I can't fix the Uni-Vertical the import route may be the way to go? John.

 

[bazmak]

From the photo I see 2 screws either side of the locking handle
Wont those adjust the gib plt and tram the Y axis ??

 

[blockmanjohn]

Those two screws, along with the center one which is used to lock the z-axis, thread into the gib. Now that you mention it, it might be possible to place a shim washer between the gib and the casting on the lowest screw. This may pick up the front of the knee a bit. Thanks for the thought. I'll check it out tomorrow.

 

[MachineTom]

The knee needs to be adjusted. Don't just stick shims here and there. Those adjustments screws are for doing that. Since you likely have wear on the surfaces, you may have to give up some travel at the ends of the knee range to have better team in the portion you regularly use.

After adjusting the knee, then adjust the bed, then tram the head.

 

[blockmanjohn]

I'm sure that I am missing some thing here but I don't see how those screws will make any adjustment to the knee. They thread into the gib and only seem to tighten the knee to the column dovetails. To compensate for the droop the knee would have to come off the column ways at the bottom a bit, and I don't see how those screws would do that.

Just for info, I placed a .003 shim between the column dovetails and the knee at the bottom of the knee and it took out the droop. If there was some way to accomplish this with the screws all would be well.

Like I said earlier, I am probably missing some thing and need a little more information on how to adjust those screws. Thanks, John.

 

[MachineTom]

Let me see if I can explain this well. the knee follows the dovetails cut into the column and the knee
castings. The gibs is angled, so as the gibs is pushed into the dovetail angle it pulls the knee casting with it.
That adjustment is made by loosening the jam nuts on the set screws, then turning in the set screws. I add
there are the SHCS that hold the knee to the gibs, those would need to be backed off slightly so as to allow
the adjustment set screws to move gibs. After tighting the set screws, you then tighten the SHCS, and check
the travel on the knee by raising and lowering it. You will find that travel at each end of the knee range is much
tighter than in the central portion which has more wear. The idea is to find a point where the table is snug
as you want and still movable near the extreme ends of the range.

 

[blockmanjohn]

I followed your very clear directions and found that the top SHCS had been adjusted too loosely. Upon tightening it a bit it did indeed take out most of the droop. I can certainly work with what I have now. Thanks again, John.