How to Clamp for the Outside Profile

[stang5197]

I need to mill out 50 of these clamps. They are made from 6061, but I am having a hard time figuring out how to hold the part to mill the out side profile.

The thought was to mill the 0.75Radius; Interior Triangle; and the 1.50Radius with the flat stock is held in the vise.

Any suggestions on how to clamp the part so I can mill the outside profile?

The part is going to be cut on a Haas VFOE mill.

[Geof]

Have the material stick out of the vise by a distance slightly larger than the radius around the edge.

1) Do the milling you mention, face the top and put the radius around the profile. This might mean you have to do the outer profile part way down but make it a few thou oversize. Do the triangle hole right through and put on the top radius.

2) Face and tap the ends on the large semicircle and do the hole that passes through the triangle.

3) Make a simple fixture that locates the part with a triangular boss in the triangle and a step the tapped ends rest against.

Clamp the part to this fixture with a strap across the semicircle and finish the radius around the rim of the triangular hole. Have the program stop and not put a clamp in the triangular hole just resting on the radius and take off the other clamp. Now finish the part.

I think I remembered everything .

An alternate way is to drill and tap the holes and the hole that passes through first then bolt the part to a block held in the vise. It should be possible to do everything from this block just by flipping it in the vise.

[stang5197]

Thanks Geof, I thought about the threaded blocks option but was concerned about chatter on the opposite end.

I will give it a shot, we can always add another clamp if necessary.

[JROM]

Mirror the part so you have a large round hole in the middle. Make up your stock sized for two parts with a half inch cut area down the centerline. Now finish the elongated round thru pocket in the center. Put a flat piece of Alu. in the vice and cut a male version of the elongated round pocket, add a few tapped holes for clamping down the part. then put TWO parts at a time on your little fixture and cut All the outside stuff. Saw them in half and finish the last faces and put in your tapped holes. Two Bangs for one buck!!! The flats on the inside profile will clock the parts for you. Good luck

[Geof]

Originally Posted by JROM Mirror the part so you have a large round hole in the middle...etc..

Brilliant! Why didn't I think of that?

EDIT: Removed superfluous comment

[b0gh0s]

Not to pile on, but you could cut the blank stock to the appropriately sized rectangle, drill two holes in that cutout area (inside of the part) first. Then screw the part to a steel "jigging" block, and mill the outline of the part. Do all outer edge finishing, and then clamp the part and do the cutout in the middle.

I do bearing blocks and a bunch of small helicopter parts this way now, seems to work pretty well.