I am running the first small batch of AR10s right now. This was a fun job to setup and try to improv over how they are doing their AR15s.
Basically I have been saying that they should do AR10s since I started doing work here, I was always told no we will never do it. Then one day well I was way deep in the pistols they decided to do AR10s randomly. I could tell the pistols were still a ways out but I knew AR10s would be an easy thing to do.
They did not want me to do it because I had so much to do with the pistols. I tried to convince them to pause the pistols for a month, lets get AR10s going then get back to pistols. That was a no, so we said hey lets just wait till the pistols are done then we will do AR10s. One project at a time. A week later they tell me we are doing AR10s but they are going to have another guy come and manage that project and handle everything. This is an very experienced older machinist who works for one of the owners other companies. He has set up a lot of the machines here before I started.
I knew it was going to end with me doing most of the work though. Right away I had to do all the CAD work and design it. Then they wanted me to setup and program for the first 2 ops. They wanted to do this the same way they do the 15s. One machine does the first 2 ops so that it comes out with a basic shape and profile and then into another machine with a 4th axis to be finished.
No biggie that is really not much work at all.
This is how they look coming out of the first machine after OP1 and OP2
We ended up waiting quite awhile on the other guy to finish his fixtures for the other machine. No fault to him either he has so much other stuff going on I don't blame him. It came the point where he couldn't program it so it fell on me. I got no problem with that I wanted to do it really I just wish they way we went about it to get that point was different. I think his fixture is very nice, its pretty much identical to the AR15 ones they have in other machines, just a little bigger. But if I was to have done all this myself I would have done everything quite a bit different. We could have made the parts complete in one machine on the 4th axis with some slight changes. Oh well no biggie. I get paid to do things how the bosses want.
This was how the fixture looked when I first got it.
Few issues I hit right off the bat. First is the hole for the Buffer tube spring detent needs to be at 6 degrees and there was not as easy way to do that. My initial thoughts were to try to reach thru the magwell on the left side. Kinda like this.
It was definitely do able and honestly I kinda wanted to do it cuz its pretty sweet. But I would need such a long drill and clearances were very very tight. Also no way to put a flat in there for the drill, it was all just to much. I really did not want to mod the fixture at all which is why I wanted to make this work. The much easier option was to just mod the fixture, as I continued on I ended up making quite a few mods anyways.
I tilted the pads on the front side that 6 degrees. There was some toolpaths I was doing on this front side I could move the back, I was also able to easily put a flat in there now for the drill making everything easier.
You can see the modifed one on the right and unmodified on the left.
You can also see I swapped out the bolt clamps for destaco clamps. This was another small grip I had with this fixture. I don't like the bolt clamps because different operators tighten things differently and it has caused consistency issues in the past. The destaco clamps fix that and also make loading/unloading so much faster and easier.
I figured out I can get destaco clamps on a the parts. I have not gotten that far yet but it is the plan.
Another goal I wanted to do was to reduce as many external operations as possible. The less times the parts needs to be handled the better. The first one was finishing the magwell in the machine. We have broached mawells in the mills before but that is pretty tough on them. I decided to drill out the corners and then do a finish pass with a smaller endmill. It comes out with great fitment and has no downsides. Unless you don't like the corners now but you really never see them and they don't function any different then square corners. At the price point this gun will be sold for it is really not something you can complain about it my oppinion. Maybe if it was a $3k gun I would say it should be broached but it really makes no difference.
Lastly was the pin hold for the bolt catch. Right now it gets done in a drill press after final machining.
This is because it is so long and a small diameter it will wander very easily. You really need a guide block to do it, like the fixture we have here on this drill press.
The way the fixture is setup I was able to use it as a guide block. I drilled a hole thru the fixture. It startes out a little bigger with a larger chamfer to guide to the drill in. Another thing you have to do in your programming is drop the drill into the guide block before turning the sprindle on. If you don't do this the drill will flex and then snap. So you drop it in, start the spindle, drill the hole. Then you pull it out of the hole but not the guide block and stop the spindle before pulling it all the way out.
So far its running good. Making small tweaks and stuff here and there but running the first small run of 20ish. really happy with how they are coming out, even adding external processes in I still was able to reduce the run time from what our AR15s are. In my opinion that is a major win.
Sometimes it makes out some wild ideas, I am a little bias tho....
