Sunday, June 1, 2014

Made good progress on the AR lower

I got one fixture made during the week. The second one I finished today and then started on the AR lower. I figured why spend money on a 80% when a blank is cheaper and both require milling. I picked up two forgings at the machine gun shoot. They were $20 a piece. Guy wanted a decent chunk of cash for a fixture. The fixture is aluminum. No drill bushings, nothing fancy, and cost the price of a lower. So, I ordered a chunk of aluminum plate off of fleabay, and made my own fixtures. I found a print on the web for some fixture plates which allow you to clamp the forging in a vise or to the table where it is stable. The aluminum stock was around $15. I will drill holes without the use of an aluminum plate with holes thank you.

Start with a slab of aluminum, cut her down, and true it up into two pieces.

Here they are with clearance cuts so forging will fit flat. Still need the ten degree cut to clear magazine well.

Here, the ten degree has been milled into pieces. They are now ready for use.

Later on, both clamp plates will be used in vise for milling the magazine well as well as the trigger group.

But for now, I use one so I can clamp it to table and indicate it true. It took three shots for me to get it in the spot where I could hit all sides without running out of travel as my mill isn't huge, and my brain fails to look too far ahead. This picture show the first time I clamped it. I wouldn't have been able to mill more than the surface I am indicating if I hadn't of moved it.

Here, I have milled the the area the upper shall sit in. I managed to acquire a 1 1/2 inch diameter end mill off fleabay for six bucks, eleven if you count shipping, so I didn't have to fudge with getting the .750 radius right. It also made quick work of milling the area out. I also did the flat on top of where buffer tube goes.

Next cut, milled area where buffer tube enters to print. This is it for this set up. Now to make it where I can clamp it to drill holes.

Brought home one of my angle plates from work. I used one of the clamp plates to hold it parallel. I put a flat spot where the mag well will be milled out. This will give me a flat place to clamp to for next setup.

Tomorrow, if work doesn't beat all the life out of me as Mondays tend to do, I will start drilling holes in side, but for now, I will mope in front of the TV dreading Monday morning. At least I got a good start on it.