Workholding AR15 Forged Uppers or Lowers?

Does anyone know how a Forged upper or lower for that matter are held for your initial cutting. I know these days a probe can be used to locate the material but in the last 50 years there must be a faster method?

How many are you trying to make? Is it going to be recurring? How much do you want to spend?

These are all important to help you, otherwise you may not get an achievable answer.

I have an inquiry for 2000. Currently I make billet on our horizontals and have all tooling, would just need to build fixturing.
I build the billet in 2 ops but cannot think of a way to do that with a forged part, 3 ops with probing the part is all I can come up with but probing 2000 parts at 1-2min ea probe costs a crap load in time overall

I've had a zero % forged for about two years just collecting dust in the cabinet. I found it much easier like you said to just spin one out of bar stock.
Guys actually producing these for profit aren't gonna help you out on Work-holding.

If you could cut the picatinny first you could do all the other op's using a 90 degree dove-tail fixture.

I've never worked from a raw forging - like most say, for small qtys, it's much easier to just machine from scratch out of *cough* "mil spec billet aerospace grade aluminum".

I'd go with soft jaws milled to hold the bottom half of it, relieved where you don't need the meat. Probably locate so the lugs are set on a step in the soft jaws.

I haven't looked at the proper drawing for an upper receiver, so I can't say what'd be best to hold it by, but I don't know that the recoil slots on the upper rail are best or not. One - most dovetail vises rely on sacrificial material and you don't want to mar the finished surface. Two - the dovetail feature may not need to be accurately located along the receiver.

Might be best to hold the as-forged dovetail and machine the bottom end including the attachment pin holes. Then you can locate everything on a fixture that uses the pin holes for location.

I used to make AR-15 uppers, 160,000+ a year, from forgings just like that. I ran the 3rd milling operation and sometimes the second.

The first operation was gundrilling and reaming a through hole the length of the part. Fixturing on the first op. utilized a shop-made clamp that held the forging body by the sides. There were "pads" that were ground to the same general contour of the forging body, at a point that was consistent part-to-part. The tolerancing of the concentricity on the through-bore was such that some small variation in parts still produced a good part, but what helped the most was relatively consistent forgings.

The 2nd op. utilized mandrells holding in a rotary fixture in the through-bore (vertical mill) and 3rd op. clamped over the dovetail rail and flat bottom (horizontal mill). There was even a 4th operation, though with more modern equipment the parts could have been made in fewer steps.

Do you have a sampling of forging that you could inspect and see how consistent they are?

I made some jaws for my 6" Kurt to hold the lowers for machining. You'd have to start with something like this for the 0% in order to locate and drill the holes for the take-down pins but once the pin holes are done a wider set of jaws could be used with "pins" built in to indicate the lower to the jaws.







I showed how I used them on some 80% lowers - ArcaneIron.com • View topic - AR 8% lower build in a "professional hobbiest" kind of way.

-Ron