Sunday, September 18, 2016

Upper, part 1

Still need to blue and engrave lower, but it is done and functional. Still need to find missing sight. May rob a scope off of the one of my other AR's to use. Just don't want to have to sight it back in as it is set perfectly for the rifle it is on.


I figured it was nice out, so I wanted to play in the garage. I started machining on the raw upper casting. Had to think about how to approach it. I figured, looking at the blueprint, most dimensions come from the center of the hole, so, I figured, square everything up so I can hold on something. Next up, find the center of the thread boss and drill a precise hole, followed by, drilling a hole through.

After several attempts, I came up with this one to hold part while making first cuts. I did the top first.

Here, I did the front of the thread boss, the rails, as well as a cleanup cut on the back face. I figure this trues up three of the four sides so I can rest on any surface to machine another side. I am not finishing anything at this time, just squaring things up so I can grab them in a vise, or clamp to an angle plate.

 Here is the clean up pass on back side of upper.

Now, I was able to flip it, put it on parallels in a vise and cut the panel on the other side. This pic doesn't show it, but I also did a clean up pass on the top and front of the two nubs so as to square them up if I should need to clamp on them later.
I clamped the part to an angle plate, using a second angle plate and a parallel to square part up and support it for drilling operations.
I center drilled the part, followed by drilling through with a 1/8 diameter drill. I drilled about half way through, when I needed more clearance for flutes of drill. I ran a bigger diameter drill down most of the way, leaving some of the 1/8 inch hole for the drill to follow. In the end, it did walk off center, which I pretty much expected, but hoped against. It only walked about .060 to one side (but did stay centered up and down). So, plan B.
I clamped it the other way and used a center cutting end mill to center things back up. I used my extra long 3/8 end mill from the lower project. I followed this up with a 1/2  end mill. I will do the same on the other side. My new plan is to use a 1/2 dowel pin on each end to use for indicating center of hole to use as a datum point.
This is the other side also opened up and ready for the dowel pin. This should not have been such a long job, but my mill is extremely primitive. I have little travel on the ram and have to move the head up and down frequently for height changes, which is a real PITA. I really want to upgrade my mill. I believe I am going to buy myself a Christmas present this year. I know what I want, and the travel on it is a lot more, plus it is built a lot sturdier than this one. Plus, it is variable speed. I bought the one I have now off Craigslist, which is probably how I will get rid of it when I upgrade. The new one will be a table top model again, but bigger. It is also upgradable to CNC.

I am hoping on moving next year so as to get a bigger garage. Am watching a house about a mile down the road. It has possibilities, if the price drops. It only has a 1 1/2 car garage, attached, but, it has a bit over an acre of land. Plenty of room for a pole barn and/or garage. In that case, the attached garage would become the shop. I would then be looking for an actual Bridgeport at some point down the line. The new table top mill at that point would turn into a CNC at some point. Only reason I am really hesitant on that house is, school is back in session. I need to sell this house to move. This subdivision sells immediately during summer break. It is a perfect family subdivision and people tend to move more in the summer when school is out. There are a few houses for sale in my neighborhood now, and they aren't moving. During the summer, average time on market in this subdivision was a few weeks. If he drops the price on the house, I may have to go for it. It does have hardwood throughout and a walk out basement. House itself is fairly small, but the property would make up for it. A garage would be built immediately at time of sale as I would have it in the mortgage. I love my house, I just hate having to pull the car out to do anything. During winter, it is hard to pull the Vette out and get it out of the way. I could definitely get a lot more done with more room.

Tuesday, September 13, 2016

All done

Well, still need bluing, engraving and the stock, which I have on the way. It does cock and dry fire perfectly. Safety works. Everything is smooth. Package should be here Friday according to tracking info. Hopefully take it out and try it at the range this weekend. I found one of the two sights so far. Still trying to find the second one. I eat at my couch with my dog, so, the kitchen table is usually my work area, where I found one of the sights. I am sure the other one is in one of the bowls of gun parts. I will find it.

Here is the right side. Magazine slides in and out like butter. Have two magazines so far. I am very anxious to try the 9mm out.


Here is the left side. Everything is smooth. I did have some tweaking to do. I forgot to open the hole for the roll pin on the bolt catch. I had drilled a pilot hole all the way through. I forgot to follow it up with the finish size, oops. I also forgot to widen the bolt catch slot on the top of the lower. I used a 1/8 end mill, but forgot to open the slot to finish size. Found these oversights out last night while trying to assemble. I also forgot to finish the trigger opening to finish size. Fortunately, I found all problems yesterday and fixed them as soon as I got home. Well, after letting Spike out for a sniff around the yard, and, mowing the lawn. I believe it turned out good for a first try. I did learn a few things to look for when starting on the next blank forging. The bottom of the trigger pocket is paper thin. I figure I will take less stock off the top of the next upper to allow more stock in this area for machining. Shouldn't harm anything, just not happy about it. I do want a better mill, but am trying to hold out another year. I have been house hunting. I am leaning toward moving next year. Hoping on getting at least a three car garage, or a 2 car with a pole barn out back. This would allow for a real mill. Have seen a few with walkout basements, which would also work. I would so love a shop in the basement. Be able to play comfortably year round. I want a Bridgeport, just no room. Have had opportunity to get one, just nowhere to put it at present.

Sunday, September 11, 2016

Almost done

I have one small chamfer up by the charging handle to do, and one small hole to drill and tap in the threaded portion of the buffer opening. Then, just the bluing and engraving.

I finished threading the buffer area. Had issues mid threading with the drive belt on the motor. Always adds a bit of fun to the game. Picked back up on the thread and finished it. Next one, I am going to thread mill the buffer end.


I used the extra long end mill to finish pocket. I got the mag well where a magazine would slip in, but the 9mm mag adapter would not slip in. had to file it until it would slip in. Made sure 9mm mag slips in and out with ease as well. This one will stay a dedicated 9mm lower. I want to map the opening and make another lower with the 9mm mag opening in it, without having to use adapter. I have extra blank forgings. They are only $20 a pop at the machine gun shoot. I picked up some upper blanks as well, thought they look a bit more tricky on the machining. I am going to try and do at least one upper. Would like to do a whole upper, lower and trigger assembly from metal stock just to have a gun I made from scratch.
Here is the mag fitting nicely in the lower. At this point, the magazine slid in and out nice, but, the 9mm adapter was too tight. I filed the opening until the adapter fit in snug, but not too tight. It will come out only to blue the lower, then it will go in to stay.
Right hand side done. The blank forging like the one it started as is above it for comparison.

Left side done. Again, the blank above for comparison.
And a shot of the top. A lot of work, but it was fun and productive. I will finish the couple minor items tomorrow and dry assemble the whole trigger assembly, buffer tube, upper and magazine to make sure all fits are good. I tried the magazine release hardware earlier and know that works well as does the handle assembly. Upon checking out the pictures as I am doing this write up, I noticed I forgot to mill the bottom trigger guard groove, which is no big deal. I left it flat so I could hold on the flat bottom in the vice. I no longer need to mill off of surface, so I can finish it now. If I get it done tomorrow, I will post pics of the finished product. May take it to the club later in the week to try out before bluing and engraving. Like to make sure it works. Anxious to try out the 9mm upper and see how it works. Have a lot of 9mm ammo.

Thursday, September 8, 2016

That was quick

My extra long end mill showed up four days early. Definitely going to order more through them. Got home and finished boring the hole for the threads. Found a better boring bar than the one I was using, but not my good one. It cut straight, no push off. I am going to tear the office area apart tomorrow night. I have looked all over the garage for it. Why it is not next to the lathe I don't know. Has a nice threading insert in it. I can use the one I am using if need be, but the carbide insert is new in the one I am looking for, and probably a bit more accurate than the hand sharpened high speed one I made. Should finish up Saturday morning if I remain off the work list. There is a steam show this weekend in Elnora I usually go to. I am leaning toward just working in the garage on some projects. See what I feel like doing.

Wednesday, September 7, 2016

Made my fixture for threading the buffer end of AR lower




Much like me, it ain't pretty, but it does work. I took a piece of 1.5 inch round stock and milled .125 off a section of it. This gave me a flat area to screw the lower to, and, it also centers the buffer hole (which is .625 above flat) when bolted together. Still have to center it side to side, but, that is pretty simple.

 Next, I needed a way to clamp the lower to the fixture. I fashioned a plug that will fit in the roughed out magazine well. For the next lower, I will use the same fixture, but, I will drill and counterbore through it and tap mating holes in the solid pocket area of the lower.


I drilled the holes to match those in the fixture. I bolted everything together, then, removing one bolt at a time, I used an end mill to make a flat so the bolt would tighten down straight, instead of angled, so it is nice and solid. Repeated for all three holes.

Ready for lathe. Like I said, she ain't pretty, but it is solid. Much more rigid than I thought it would be. I milled a couple flats on the side to put a brace on each side if needed. The flats are the same exact width of the outer surface of the lower. For now, I don't think I will need them, but if need be, they are there. I have some 1/8 flat stock I can easily make clamps with.
Here it is mounted in the lathe. It clears the bed easily. It is very rigid. I indicated the face true and centered the hole side to side, then, tightened everything down. One more check to make sure nothing moved.
I couldn't resist trying it out. Too late to finish the hole, but, I had to know if it was going to work. Once I got the hole trued up that I drilled in there (The drill kicked the piece to the side a bit and the hole was way off) when it was in the mill, it cut clean with no chatter. That is, until you hit the area where the threads are only on one side as it ramps down. It pushes off a bit here. It works out though. I am careful and slow the feed down (I kick the feed lever out and feed really slowly by hand) in this area as it lopes through the ramp. It forms an undercut on that side from the slight kick. Hard to describe, but I will take a picture of it when done. I hope I can figure out where I put my good boring bar. I have a threading insert in it, and it is the perfect size for this job. Thick enough to be rigid, but small enough to fit. Thought I had it in my Gerstner box. I have a few more places to look. I would like to finish the buffer area tomorrow. I am off again this weekend, if they don't change their mind. Hopefully my end mill arrives and I can finish the magazine pocket. Then I can blue it and assemble it. I still need to engrave it as well. Haven't figured what all to put on it yet. Been getting ideas online. Lots of recommendations of putting a serial number on it. One guy had a decent idea. He engraves his NRA member # followed by what number receiver he is on. That way, if law enforcement looks at the gun, you don't get grief for no serial #. Using a number you can remember helps if you need to report it stolen, so the NRA # is on your card, and unlike your social security #, you don't really care if someone sees it.

Tuesday, September 6, 2016

Back to work, bah humbug

I ordered the end mill to finish the magazine well. Hopefully be here by the weekend. Had an idea for a fixture for the lathe to hold the lower for boring and threading the buffer hole. Got it machined this evening. Need to pick up a few socket head cap screws tomorrow to try it out for rigidity. Wish I had thought of it before hollowing out the pockets, but, I made a couple of side plates for the fixture which should steady it up quite a bit. I will find out tomorrow. Be nice to finish it this weekend. Like to try it out and see how it works. I have a couple more blank forgings. I am going to try and make another one with no flaws. I have a block of clear poly carbonite that I want to make a see through model of for display. Think it would look cool and be able to see the inner workings. One step at a time. Hopefully get the weekend off again. Not holding my breath on it though.

Monday, September 5, 2016

It is a lot lighter now

Got the trigger area cleared out. She is a lot lighter now. Just have to thread mill the buffer tube threads in it, and finish mill the magazine well. Need to get a extra long end mill to finish the mag area. It does fit nicely though. I have a couple minor blemishes in it, but it is functional. Not bad for the first one.

 


I started off by finishing the mag release slot on the top of part.

It is easier to mill pocket if you drill holes to remove most of the material. These holes go about .010 shy of hitting bottom of trigger pocket. Want to be able to cleanly mill the bottom with no imperfections.

  The last three holes are smaller, and shallower. Same idea though. Want to remove material and it gives you a visual for where the end of the pocket is so you don't run past it when milling.

Here is the trigger portion of the pocket milled out. It is still rough in this photo. Forgot to shoot one when I had this portion finished, and before moving on to next portion of pocket.
Here, pockets are done. I didn't take a picture of the small trigger opening being milled out, but, there really isn't much to it. It is done, just no picture.
 It is a nice tight fit. No slop, very little daylight at all. Don't want to install trigger assembly until I have the buffer area threaded and the magazine well finish milled. Even then, I want to blue it before final assembly. May make a slightly undersized pin to temporarily hold magazine release lever so I can dry fit everything. That roll pin is a real SOB to get in and out. I made a small block for use as a guide to hold pin when hitting it in, if I can find it. It is just a hole in some keystock, so nothing fancy, but it works. Don't want to scratch up the finish when I finish assemble it.