80% questions

[Lostsheep]

I am going to be finishing my own 80% lowers and some of my friends have expressed an interest in doing the same. I am a cnc machinist by trade and I will be making my own jigs and writing my own program(s) to finish the lower. I have tried searching and can't find how much work my friends would have to do so that we remain legal. I am not taking any chances until I understand where the limits are.

So, do they have to write their own programs and do their own setups? Can they use my program and do their own setup? Can they use my program/setup and just press "go" on my mill? Do they just have to be present while I "help" them?

Honestly, once programmed and jigs made, the cycle time for a lower can't possibly be that long. My initial inspection looks like 2 su's with some pocketing and some holes. For those of you with cnc's, how long was your cylce? Was it 2 su's?

Thanks

[CHAD PEZZLE]

Two setups, One on the CNC was about 10-12 minutes including change over. My second set up if you'd call it that was drilling the trigger pin holes and the safety selector hole on a drill press. Pretty easy stuff.

Don't really have an answer for your other stuff.

Chad

[leelaw]

Essentially, all they (whoever will be the "manufacturer") really have to do is setup the receiver or raw materials and press the GO button on the CNC machine.

[darkcbr1000rr]

My cycle time was 16 to 18 minutes. I slowed the feed rate down about 25%. Too much chatter when the endmill got deep. Go to cncgunsmith.com to download his igs file and then convert it over to you cam software. That's what I did and just put a tool path on it. I used three tools, 3/8 drill bit, 3/8 carbide endmill, and a 1/4 carbide endmill. I don't have to tell you, but just in case, hang the endmills long enough to clear the reciever when milling the back shelf pocket. Have fun with it. If you need more help pm me.

[Lostsheep]

My cycle time was 16 to 18 minutes. I slowed the feed rate down about 25%. Too much chatter when the endmill got deep. Go to cncgunsmith.com to download his igs file and then convert it over to you cam software. That's what I did and just put a tool path on it. I used three tools, 3/8 drill bit, 3/8 carbide endmill, and a 1/4 carbide endmill. I don't have to tell you, but just in case, hang the endmills long enough to clear the reciever when milling the back shelf pocket. Have fun with it. If you need more help pm me.

I got my cad files from there already, that sure is a nice thing to have access to. I also downloaded his blueprints, can anyone confirm that the tolerances are correct for the pocket?

darkcbr1000rr,
Nice to see other san jose machinists in here.

[darkcbr1000rr]

I had to use cutter comp about .006".

[savs2k]

for your friends youre just providing the tools. You should be able to set up for them and technically (i heard it from somewhere before but dont quote me) as long as they hit the start cycle button they MADE it themselves. There is an old thread about this if I have time later ill look it up for you

[Roccobro]

for your friends youre just providing the tools. You should be able to set up for them and technically (i heard it from somewhere before but dont quote me) as long as they hit the start cycle button they MADE it themselves. There is an old thread about this if I have time later ill look it up for you

If you could find that thread I'd appreciate it.

Justin

[savs2k]

i'll try to look through my old posts later tonight. Knowing myself and the given topic of making my own firearms im sure i posted something.

[Woodymyster]

20 min cycle time for the pocket... going quite slow

[Lostsheep]

I will be making my own jigs

You know, for $125 I may just have to buy the jigs, that really is a bargain.

[Roccobro]

You know, for $125 I may just have to buy the jigs, that really is a bargain.

If you can split it a few ways it gets even cheaper. And same with the tooling. There are those of us that have used them and now rent them out.

Justin

[Lostsheep]

If you can split it a few ways it gets even cheaper. And same with the tooling. There are those of us that have used them and now rent them out.

Tempting, but I am in the work holding business and a I collect jigs of all kinds

[savs2k]

i have the ar jigs if you ever just wanted to borrow and make afixture.

[darkcbr1000rr]

20 min cycle time for the pocket... going quite slow

Wasn't too long. The noise was just way too unbearable. Like a 5 year old screaming in Denny's. 20 minutes beats an hour and forty minutes on the manual mill, though.