EDM Pricing Question AR-15 Magwell

[bill south]

Hey Guys;
I have some AR-15 zero percent forgings that I would like to have the mag well cut out. I have a small CNC that I can do all the machining but the mag well would be very difficult. I have prints and can even provide g-code from bobcad if it would help. Most important is that the work will not be illegal since it has nothing to do with the fire control group according to the BATF. So, it's just modification to a paperweight.
I have several of these to do (Christmas pres ants last year from my bro), and they will all be for my personal use and I may do one for my BRO.
Any idea what I can expect to pay? Is it even practical??? I don't know anything about EDM pricing but I've seen a couple of forgings which were edm machined and they were beautiful.
Thanks and any information or advice will be appreciated.
Bill

[bill south]

Is there a better way to cut the magwell other than EDM? I don't seem to be getting too much help with this question.
Doesn't anyone have an edm machine sitting idle. Again, forgive me guys, I don't know much abaout EDM.

[skullworks]

Bill;

All the big boys use a monster broaching machine to finish the mag well.

Its quick, easy and almost idiot proof and the size will remain consistent as the broach wears so they only need to gage one about every 50 units.

That said for custom shapes Wire EDM is the easy way - but its going to cost - as in just the wire cut will cost you more than the out the door cost of a name brand receiver from your local gun shop.

You CAN completely machine the mag well yourself. Its a pain but it is doable. There are 2 options.

1] Is standard drilling and milling complete with some hand filing fitting.

2] Is based on the above but adds a step - You will make a guide block that will fit in the mag well as machined and has a corner step milled in it on diagonal corners to act as a guide for a keyway broach. You have to broach each corner twice, once for each side of the 90 degree corner.

I was a Type 07 for 12 years... I made many AR's - its not brain surgery.

[imprez55]

I second what skullworks says:

Originally Posted by skullworks You CAN completely machine the mag well yourself. Its a pain but it is doable. There are 2 options. 1] Is standard drilling and milling complete with some hand filing fitting. 2] Is based on the above but adds a step - You will make a guide block that will fit in the mag well as machined and has a corner step milled in it on diagonal corners to act as a guide for a keyway broach. You have to broach each corner twice, once for each side of the 90 degree corner.

The third option that has crossed my mind recently is the DIY sinker EDMs. Saying you have more than one forging makes this an even more viable option as it would be the initial investment that would be the biggest cost (around $300 if I remember correctly).

In the EMD section there are plans to basically retrofit a benchtop cnc machine temporarily. I have not tried it and do not know how well it will work out but through links and such there are people using graphite electrodes into files with minimal wear. I would imagine that would be comparable to going through the inches of 7075 (or 6061, whichever you prefer). When I finally get around to making an ar-15 lower I will try to scrape some money together to try the sinker EDM method (I try to do it on the mainspring housing and magwell for a 1911 as well)

Any input as to using the sinker EDM method guys?

[Joezx10r]

http://cncguns.com/projects/ar15lower.html U can read how this guy done it in two setups from top and then from bottom and finished out the radius with a file.

[bill south]

Thanks Guys;
I have completed a couple of receivers by using the mill/drill/file method and it's doable but quit a PITA. I kind of like the idea of a sinker EDM to play with. I found a schematic on the web and have put it on my list of things to do. It's just after the CNC router I'm just finishing, the 65 mustang that is completely dissassembled and just needs "putting back together" and the 300 whisper that I want to build.
Seriously, I really do appreciate the information and was expecting the cost to be too high for my small projects. But, lotz of food for thought.
Everyone have a great day.
Bill

[sodickappsguy]

the last two shops that i helped setup for cutting out the ar-15 mags took around 20-25 minutes per part. see what a local shop will charge per hour and see if they will work out a deal for some idle machine time.