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S&S_ShovelHead
09-28-2012, 03:16 PM
Im sure there is a simple and obvious answer to this but Im pretty new to machining.

The situation:

I have 4 roughly square peices of 3"X3"x3/4'' CRS that butt up to make a box. The connect via pins and bolts. Two pins and two threaded holes on the side that butts up to a face and 4 holes on each face, 2 for each pin and 2 for each bolt to pass through. I put the 4 peices side by side and inserted 2 long pins through the holes on each face so they were lined up then I face milled the side that had the pins (pins were obviously removed) so that I had a precisely square box when butted & bolted up but now I need to make the bottoms flush with each other as I will be bolting a bottom peice on.

Evan
09-28-2012, 05:14 PM
Put it in the 4 jaw on the lathe and fly cut the entire bottom. Use very light cuts and low rpm to reduce the interrupted cut shock to a reasonable level.

Toolguy
09-28-2012, 06:41 PM
One of the easiest ways to make something square is to true up the fixed jaw of the mill vise with an indicator in the spindle, parallel to the X or Y axis, depending on how the vise is mounted. Once that is done, clamp the part in the vise with the end to be machined a little past the jaws out in the air. Then it's a simple matter to use the side of an end mill to trim the part exactly square to the sides that are clamped by the jaws. If an end stop is used opposite the end to be cut, any number of parts can be made the same length so long as the stop is secure and doesn't move.