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AR10 80% magwell EDM

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10 years 10 months ago #33923 by faawrenchbndr
Replied by faawrenchbndr on topic AR10 80% magwell EDM
Good point about the 3 degree tilt,........still easily accomplished with a mill.

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10 years 10 months ago #33962 by OleCowboy
Replied by OleCowboy on topic AR10 80% magwell EDM

Coner wrote: Use of an EDM to cut the magwell on the AR10 is more critical than an AR15 cuz the magwell is offset 3 degrees on the AR10. AR15 is straight up/down. Magazine fitup is not the concern.

As a former machinist (AFL-CIO-IAM Dallas Love Field Local) in the airlines industry and in the manufacturing sector (munitions) I can assure you standard mechanical machining practices will give the same results at much lower costs. EDM is superior to conventional tool work, but I know of no requirement even with a 3 degree offset to mill out to the millionth of an inch, its simply not that critical, nor do I see a significant benefit in doing so. There are applications of this technology that lend itself to enhanced accuracy and for those who shoot a tighter group than a pie plate.

You will find there are even some AR 308 manufacturers that employ forging for their lowers rather than milling so the tolerances just are not tight.

If you want use EDM that is certainly your choice and you stand to lose nothing in the process, but your weapon would be better served if it applied to the bolt bore and races. Maybe you can get a better cost by having them do more work with the EDM, most shops will discount for more work performed. Let us know what you do on this...
The following user(s) said Thank You: Coner

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10 years 9 months ago - 9 years 5 months ago #34002 by Coner
Replied by Coner on topic AR10 80% magwell EDM
...
Last edit: 9 years 5 months ago by Coner.

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10 years 9 months ago #34004 by faawrenchbndr
Replied by faawrenchbndr on topic AR10 80% magwell EDM
Sounds like you could farm out the magwell, then finish the pocket cuts, pin and safety holes on a end mill.

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10 years 9 months ago #34008 by OleCowboy
Replied by OleCowboy on topic AR10 80% magwell EDM

Coner wrote: Good points OleCowboy

My biggest concern with the mill I can use is that it would take 2 setups to cut the magwell. It's just too deep for one setup/operation. (one plunge from either end). To eliminate any step/blending from the two different setups I would prefer a single cutting operation that I know an EDM could achieve. I'm sure the tooling is out there for a single plunge/cut but that just isn't available to me.

Obviously cost is the biggest drawback to this choice.

Like most of you tinkerers I'm just super anal when it comes to my equipment :thumbs:

There is your justification for sealing the deal.

As an engineer who practiced and lectured, if there was one thing I wanted my engineers and students to walk away with was: FORM FOLLOWS FUNCTION! A screwdriver is not a wrench, wrench not a chisel etc. You have clearly analyzed what needed to be accomplished, then chosen the RIGHT tool for the job :twothumbs: I like that...
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10 years 9 months ago - 10 years 9 months ago #34013 by SOC
Replied by SOC on topic AR10 80% magwell EDM
Oops, double tapped...
Last edit: 10 years 9 months ago by SOC.

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10 years 9 months ago #34014 by SOC
Replied by SOC on topic AR10 80% magwell EDM
EDM is a proven method of "cutting" the magwell on lowers. A few manufacturers use this process as they already have the EDM machine and this saves on equipment (Cutting Dies and press).

Most magwells are cut on a CNC mill then a cutting die forced through to cut the corners of the magwell square to finished dimensions. (FYI most mill one side halfway through then flip the lower/tool head and do the other side. If this scares you keep in mind, in the 1800s the railroad used to cut tunnels through hundreds of feet of rock from both ends of the mountain and meet in the middle often only being off by a couple of inches)

In the garage the job could be done with careful measurement, a drill press/power drill and a file. A couple wood blocks and a steady hand and the 3 degree tilted magwell on the AR-10 would be no more difficult.

If you go garage on it with a hand drill (or anything for that matter) learn how to make a jig for the job.

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