Radius on the corner of square stock

[ErnieD]

Hi,

I work part time in a small machine shop. We are in the process of setting up a job that will be made of 12L14 .500 square cold rolled stock. The pieces are 2.500 inches long and have to have a .062 radius on each corner for the length of the part. This will be a production job running 10,000 pieces and may repeat,

Can anyone give some insight as how to do this at a reasonable cost? I built a broach that we can push the parts through but it just rips the stock off leaving a very rough and "gougey" finish. I am trying this with just one cutter on each corner but have provisions to add more cutters. From my readings on this forum there are a great many knowledgeable people that contribute. It is my hope that one of these people can answer my question.

Thanks,
ErnieD

[Belding]

How critical is the radius? Is it possible the customer only wants it for appearence? Square stock usually has a little bit of a radius anyway. Maybe if you explain to them how much $ it will add to each part they will reconsider its necessity.

Zac

[ErnieD]

Hi Zak,

Thanks for the reply. The radius can be + .010 and it has to fit in an assembly that has a stamped radius something smaller than .062.

ErnieD

[cam1]

OK, dont shoot me if I suggest that you could chuck in a square 5C collet, leave sock long, and just lick the edges to get a rad? It could save having to re-fixture....

[Lew Hartswick]

OK, dont shoot me if I suggest that you could chuck in a square 5C collet, leave sock long, and just lick the edges to get a rad? It could save having to re-fixture....

Thats going to be quite a large radius nearly .35 inches. :-)
...lew...

[ErnieD]

Guys,

This was considered. We would have turned it to, I think .656 across the corners. Then there would have been very little stock to broach. The boss decided to saw the stock while it was bundled, set it up in a small CNC lathe,turn and face one end, turn it end for end and turn and face the other end. This is a very fast cycle and keeps the operator hopping. I think that we all will be having a share of this job. I must say that what we are producing is much nicer than what the other supplier was providing, from the looks of the sample part we were given by the customer. We will be trying the broach tomorrow with two sets of cutters rather than one set to see if the situation has improved.

ErnieD