80 easy......20 not so easy - finished lower

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[ARCHIVED THREAD] - 80 easy......20 not so easy - finished lower

Posted: 8/20/2014 1:02:41 PM EDT

80 % easy 20% the hard way

I have been off and on the forum for about 6 years as a lurker. Didn't think I would ever be an AR owner but this the last year and a half finally solidified the decision. I was in DC visiting a friend and we had some time to run through a Colt and was a bit impressed. It was a pre-ban version and an issue of what I now legal in my state would mean some components would not be “allowed” back in. The wife (She Who Must Be Obeyed – SWMBO) was realizing I needed to spend some time in the garage and either tear something apart or build something. I had made some Cajon's (wood drums) for the kids so they were banging about. I have a motorcycle in the garage that has not been turned over in 12 years so that would be a good project to get working on at nights. It needs all the fluids flushed, and probably the top end taken apart and all seals (cork) replaced. I was smart enough to drain the fuel and remove the battery and put in fresh oil but this is a vehicle that has always marked its spot since day 1. She noted that I was looking at various gun part sites and I fully expects the word – go get the bike running but instead she said – why don't you put a gun together. Really? Dang Gotta keep this one.

So the die was set – make an offlist US MFG Tinker Toy gun – I love the state I am in but do not like the politics and this is time to do some exercising. Soo now it was time to really get serious. I knew I wanted a Wylde silver barrel – SWMBO likes shiny shiny. Although the system is really for sloe in support I like distance shooting and have done some competition benchrest matches off basic sand bag rests. Quite fun. So that leaves 16 18 or 20 inches, bull , flutes or smooth The barrel is 18 inches smooth. The back end was easy Mil Spec Mag-P in stealth grey as is the grip. A lightweight mid length smooth handguard – no need for cheese graters as I am not making a christmas tree. I could not get it unfinished as I wanted it grey also. So it it the lovely black – may have to sand it a bit and see if I can find a ceracote to match the grips. The compensator from the same company, Low profile gas block and tube. Billet upper. Lower and bolt carrier group from the same shop. I looked at polymer and have a polymer but may not build it unless I can get a determination letter. Some folks have the cart before the horse. Finally have trying a few different trigger groups I decided on a Geissele hi speed.

https://lh6.googleusercontent.com/-1msz99PDPl8/U_SxlsIvzpI/AAAAAAAAEbI/PL0LlKiw2l0/s800/web00%2520upper%2520LH.jpg

Putting it together is a snap except for the compensator. The washer was black and oversized. Oh hey you should also get the gas block on first and gee you must have forgot that with clocking, it can only be used once. There is a hardware store in town that has a good selection of stainless steel hardware. A trip brought back an assortment of washers and some SS shim stock. After about 2 hours of careful filing I had the 2 washers at the right thickness and diameter to clock the compensator.

I ran a lead pellet down the barrel and there seems to be a slight burr at the gas port. I might run JB Bore paste a few dozen times to see if I can get it smoothed out. I should also try a cotton ball or q-tip and see if it snags it or if the pellet was just catching the hole.

https://lh6.googleusercontent.com/-e7JifXDobmU/U_SxmrIf2HI/AAAAAAAAEbY/eKrFAqJRqdM/s800/web01%2520upper%2520RH.jpg

Like I said the 80% was the easy part.

more to come...

je

Posted: 8/20/2014 6:43:16 PM EDT

[#1]

So-so attempt at satire.

Posted: 8/20/2014 7:21:19 PM EDT

[#2]

More Satire for Mr. GlorckR

My first intention was to make the pocket with a hand drill. Hold the drill as vertical as possible with my calibrated eyes and arms and use some stop collars all should be good. Finish up with either hand file or dremel.

The jig that comes with the lower was quite nice and one could tell that a drill press or mill was the proper way to go. What was I thinking – gotta find someone with a drill press.

https://lh3.googleusercontent.com/-WF_IXQF1PJ0/U_Sxm8R7AwI/AAAAAAAAEbg/mHqN84qiZNU/s800/web02%2520Jig%2520oem.jpg

Coming from the school of hard knocks I thought there should be a way. So I looked around for another option and came across the 1/8 inch at a time solution. Ah this looked much better dooh oh wait quality control. What is up with this? Humm if this is what a pro shop is putting out can I really do it better? The more I looked at it the more I figured I can really screw up the wall thickness.

https://lh4.googleusercontent.com/-Pnh4UrBQo7c/U_SxnMjDcUI/AAAAAAAAEbc/cVcZLRt1q6s/s800/web03%2520jig2.jpg

https://lh4.googleusercontent.com/-TtmA7_styHM/U_SxoKT3i8I/AAAAAAAAEbo/w0QvnNfg5lI/s800/web04%2520jig2.jpg

Dang I really need to find a drill press.

Back to the drawing board. Then a friend at work said he has a Chin-a drill I could use. They go by many different names from a Harbor-Freight to Sears to Ryobi and the yellow ones from Home Depot. The labels and cosmetic may be different but the guts are all the same. The biggest issue is runout which may or my not be corrected with a better set of bearings. In either case he had one that would be ok. Now we are talking.

After more searching around I came across a jig system that uses hand-drills or a drill press and finishes it up with a router. Cool, I have a bunch of wood working tools and a 25 year old router is among them. If you are not careful you can slice the tip of your thumb off – another ER visit.

Of course you are not out of the woods yet. The jig is designed to work with a specific lower. It does not quite fit the AR blue-print but with some creative mods it will work.

https://lh3.googleusercontent.com/-eZq3oTIXWM8/U_SxpmDQFNI/AAAAAAAAEb0/pmKVKoMjpTE/s800/web05%2520jig3.jpg

Night one
The rear meat around the back side of the take-down pin needed to be chamfered with a file (could use a Dremel if you own one). And a ridge needed to be cut down. You can see where in the photos.

https://lh5.googleusercontent.com/-TInJtZ5UQx0/U_SxpgCmM_I/AAAAAAAAEb8/NKQ_fs958gU/s800/web06%2520jig3.jpg

https://lh3.googleusercontent.com/-JBxHN7U-d-A/U_SxqOKGsGI/AAAAAAAAEcA/s9DRNsK8unY/s800/web07%2520jig3.jpg

WARNING – You will be working with tools that can do great bodily harm.
1. Eye protection is a must
2. Remove all distractions. If someone wants to talk to you stop all work before acknowledging or starting a conversation with the distraction.
3. Mistakes are made when you get tired. At first sign of a weaken state of mind or body – STOP.

Night two
Ever the engineer and knowing there can always be an improved design I stray from the direction of using a drill bit and start off with a 4 flute drill-mill carbide bit that get the some of the holes cut down with the jig in place about ¼ the depth required

https://lh5.googleusercontent.com/-L6_hwvecR0M/U_SxrJ3w_oI/AAAAAAAAEcI/xAs6II2LYWs/s800/web08%2520drill%2520mill.jpg

I try the drill as per the instructions but man I just don't like it . It works but the drill-mill bit is too sweet.

https://lh5.googleusercontent.com/-hyrV3OAnA5c/U_SxsJA06CI/AAAAAAAAEcY/3pT7jH7mUXI/s800/web09%2520drill.jpg

I take the jig off and finish a few holes to within a few thousandths using the drill press.

https://lh4.googleusercontent.com/--hZnDRgsisk/U_Sxrz8Q-QI/AAAAAAAAEcU/mOM0dfxKMfU/s800/web10%2520drill%2520mill.jpg

Night three
Unfortunately I have chewed the bit to heck. Either I was working the feed speed to fast or the run-out was too great but the cutting edges of this bit are toast. What go slow? I feel the need for speed.

https://lh3.googleusercontent.com/-Vh_FyGAUDLc/U_SxsuXoGqI/AAAAAAAAEck/x2TU-OVS4nM/s800/web11%2520drill%2520mill.jpg

https://lh3.googleusercontent.com/-MxnZEsBsnu4/U_SxtMiOkuI/AAAAAAAAEc8/VHsROv-QITc/s800/web12%2520drill%2520mill.jpg

Night four
I finish the jig cuts and think, “wow, that is a lot of cutting to do with a ¼ inch mill on a high speed router. I think I will see about running down the middle of the cuts. I pull out an end mill and start to go to town. In one corner the bit keeps walking off. Spinning the jig around doesn't seem to be of much help so I stop for the night. It's good progress about half way done with the drilling.

https://lh5.googleusercontent.com/-Z3Mb-47vFKw/U_SxtW4jprI/AAAAAAAAEco/D8xzQx85zVQ/s800/web13%2520drill%2520extra.jpg

https://lh3.googleusercontent.com/--FjHYlhH-bI/U_Sxt74nJDI/AAAAAAAAEc4/tMqObbPu4-s/s800/web14%2520half%2520drill.jpg

Night five
Starting up again where I left off. Almost done please oh please don't mess it up at this point.

https://lh4.googleusercontent.com/-IpNKu2gpmL8/U_SxuvzJc9I/AAAAAAAAEdA/JiInf1dAoa4/s800/web15%25203%2520to%2520go.jpg

I make another cut and realise I am over the line after drilling down ¼ inch. I reset the position of the drill and continue down – of course I an still over the line but I don't realise it. I should have stopped for the night but pressed on. All goes almost ok up until the point the bit grabs and stops the press. What I do not realise is that when the press stopped the table tilted by about 3 degrees. I realise this with cutting fluid and chips start making an appearance where they should not be. Dang it. I hope I didn't blow it.

https://lh3.googleusercontent.com/-fKJRhoevzKU/U_SxvceVf2I/AAAAAAAAEdI/1jygf4IndxY/s800/web16%2520almost.jpg

Night six
Reset the jig and and table – Hind sight set the jig and table each time you finish a cut. And finish up.

https://lh5.googleusercontent.com/-_ZQQucB3W54/U_SxwX0n9FI/AAAAAAAAEdc/CvahGv-HmzY/s800/web17%2520too%2520far.jpg

Regroup time. The front of the pocket had 2 errors done to it.
1. I went over the line
2. Under cut into the front of the pocket
Time to pull out the JBWeld. First you need to clean out the lower from all oil residue otherwise the glue matrix will pop out. On the back side of the hole I out in some 300 knot speed tape and on the inside pocket I drizzle in the syrup and then level out the lower so it can flow into the low spots. I over fill it since it is still in rough shape.

The Lower cured for one week.

Posted: 8/21/2014 8:41:20 AM EDT

[#3]

More 20% fun – Router time
Now that all the drilling is done it is time to start on the smoothing of the cuts with the router and a ¼ inch end mill router. Again I choose a 4 flute coated cobalt bit. The router is over 25 years old, close to zero run-out – I could not accurately measure one and is large. The ones demoed by the jog maker looks like they are a lightweight version aka small motor. One day when I had my router mounted to the router table a neighbour came by and was starting a conversation. Instead of immediately stopping work I partially engaged the neighbour and for a split second my attention was not 100% on the tool an task at hand. The result – the router took the thumb nail totally off in one swipe and as it was grabbing the nail spun the thumb around and took two whack of the thumb pad – for two years I had no left thumb finger prints.

https://lh4.googleusercontent.com/-kNLQs0l2fKc/U_SxwKhb0RI/AAAAAAAAEdU/YuiKqCiEDAc/s800/web18%2520porter%2520cable.jpg

This part of the process creates very fine slivers of 7075-T6. The shop vac will keep the drifting of the slivers down to a minimum. As for how much meat you take off with each pass is about 1/16th of an inch. Yeah it is going to take some time – took me 1 day and 5 hours.

https://lh6.googleusercontent.com/-JB_Cj5g8mBc/U_Sxww5mI8I/AAAAAAAAEdk/1R1AldWFtQ8/s800/web19%2520set%2520up.jpg

After 3 passes and slivers everywhere you need to take the vaccuum and suck out the pocket. I tried to use some spray on “cutting fluid” but the speed of the router spins it off too fast and was useless. Might be ok if you have a pump system but the you run into the issue of liquid and open circuit electricity. Really not needed as you are taking off a very small amount of metal with each pass and at the end after the power was turned off the bit was cool to the touch.

https://lh4.googleusercontent.com/-Bw6beY-mVRc/U_SxxX-WMaI/AAAAAAAAEds/Xp_CWEUZFrs/s800/web20%25203%2520passes.jpg

Here you can see I am getting close to the bottom. The drill mill bit was pointed and is 1 thousandths short of the final depth. The flat (shiney) mill spot are the extra holes I drill and ugh are bout 4 thou above the proper depth. Remember my drill stop was a piece of tape so I was a bit conservative in the depth of cut.

https://lh4.googleusercontent.com/-x3DH-qoni5I/U_Sxxobpr1I/AAAAAAAAEd0/bwn_bMFi5fM/s800/web21%2520very%2520close.jpg

This is marking the centre of the trigger hole. The template is bolted onto the jig. You get it lined up and tip the drill it with a hammer to mark the centre. I should have held onto the drill press as this is the 3rd error I made. The bit actually walked outside where it should have. Again not critical but I know it is there.

https://lh6.googleusercontent.com/-QjiIEPNX_Gs/U_SxyN_9l0I/AAAAAAAAEd8/u89E5LNHnuo/s800/web22%2520starting%2520trigger.jpg

You then throw on the router plate and can go to town. The photos show the late before I tightened it down. The directions say you don't use the spacer but unfortunately my router base needed clearance over the buffer tube.

https://lh5.googleusercontent.com/-VFPKChmMAuI/U_SxyrJSA5I/AAAAAAAAEeA/gvE9drCimUg/s800/web23%2520trigger%2520jig.jpg

Not a problem, throw on the spacer and you have clearance again.

https://lh3.googleusercontent.com/-OHrDimUJngI/U_SxzZ-tmpI/AAAAAAAAEeM/8_ylWw2mlGM/s800/web24%2520side%2520view%2520off%2520plan.jpg

Pocket is done. On the forward wall some of the resin popped out. Time to drill out the pins and safety, deburr, degrease and hit it with Insta-Blak

https://lh6.googleusercontent.com/-MhK97Qn77-o/U_Sxzo9vidI/AAAAAAAAEeQ/0EtNkYl4lgY/s800/web25%25203%2520oops.jpg