Pistol project

[Jones]

Parts for pistols and micros are few and far between so when you need a front or rear portion, you gotta build them yourself.
Slowly chewing away at a piece of A36 billet is yielding the front portion w/ front sight ears and trunnion as a one-piece, piece.
Cutting the barrel nut threads would usually be a single pointing job on the lathe, but here's what I came up with.
First determine what the threads should be: Pistols and Micros have a barrel nut smaller than full-sized and minis and that thread pitch is M24-1.0.
Turn round stock down to the barrel diameter where is fits into the trunnion. .649", then machine a hole in plate stock to take that guide pin.
Stacked together, the die will self-center on the barrel nut boss. A couple of allen head bolts act as pins to keep the die from turning as you screw the trunnion into the die.

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[Jones]

Another day in my Holly Hobbie, My Little Gun Shop.

The barrel nut latch is noticeably shorter on the pistols and micros so using one off a full-size or mini isn't an option.
I ended up making my own out of a truck leaf spring. Machining is just a lot of setups for the different cuts.

Here's a tip: Machining small parts is a lot easier if you leave them attached to the parent metal to use as a "handle".
Once the part has been whittled out, it's just a matter of parting it off and finishing off the saw cut.
This latch has since been cut free and finished to the final height, the hook bent to the correct angle, and is ready for parkerizing.

 

[Jones]

Screw-ups, even my own, are a chance to learn.
While admiring my machining expertise, I managed to snap the hook off my barrel nut latch while testing the spring tension.
I distinctly remember lesson 2 in Elementary Blacksmithing being "Always normalize metal to be machined or bent.
(That was right behind lesson 1; "Don't pick up freshly forged parts with your bare hands.")
Normalizing any alloy steels to be worked will make the piece(s) easier to machine. As always; practice on some scrap material before going after a finished part.
Heat until the material is red hot. "Red hot" is not maraschino cherry red; it's hot/bright enough to be seen in a normally lit room. Too much heat can burn the steel or put too much carbon into it from the welding torch or other heat source. After heating, let the piece cool slowly to room temps. I've even covered some piece with old welding leathers or buried it in dry kitty litter.
When re-tempering after machining or forming; bring the piece to red hot and quench in oil or other medium.
>Some alloy's quenches are preset; i.e. O1 tool steel-oil quench, W1-water, and A1-air quench<
After quenching, the part may be too hard to the point of being brittle. Buff or sand the part to get the surface bright then reheat until the surface goes past "straw" and shows a blue color then quench again. That "draws" some of the hardness back and the result should be a part that is still tough but also springy.
A trick for drawing back small or thin gauge parts is to place them on a piece of 1/8" or 1/4" flat stock then heat the plate from the underside to act as a hot plate of sorts. That way you won't burn the small parts or springs by applying the torch flame directly. When your parts reach the desired surface color, Tip the plate and parts with a pair of pliers (remember lesson 1) into your quenching medium.
Some people use "annealing" and "normalizing" interchangably but there is a difference.
https://www.materialwelding.com/difference-between-annealing-and-normalizing-of-steel/

Another tidbit of information is metal "grain". All metals from rolling mills has a grain and if you've ever bent a piece of steel or aluminum and noticed cracks at the corners or along the bend-- you've discovered that grain.
Grain is usually found running with the long direction in bar or sheet stock and if you look closely you can even see it in the surface. Bending with the grain almost always guarantees cracking or a complete break. Bending across the grain is a good way to minimize that.
And yes, to be sure of shooting myself in both feet; the bend of my barrel nut latch hook was with the grain.

 

[slimshady]

Back when I was gunsmithin' part time one trick I learned was how to temper flat springs I had to make from raw stock obtained from Brownell's. Once the steel is heated and quenched, wrap some mechanic's wire around it and submerge it in the molten lead of your pot used for bullet casting. Lead melts around 620 degrees or so, and the thermostat controlled lead pots generally run around 650. The wire is to hold it under, steel floats on lead. Once thoroughly heated, you pull it out and set it on the edge of the pot and shut it off, a while later everything will have slowly cooled and you now have a spring.

IIRC, found that in one of the Brownell's Gunsmith Kinks books, probably made a couple dozen springs that way and every one "sprung" instead of snapped or bent.

 

[Jones]

Great advice, slimshady. I wish I knew half of the "shop kinks" the old timers used.
I still wander out to the scrap pile for stock occasionally. Nothing like starting with a chunk of 'mystery alloy' to humble a guy real quick.

 

[slimshady]

Old retired machinists are a valuable "humint" source of intel, most areas have a few who work out of their own little shop to supplement their retirement income. If they are anything like my Dad was, get them to talking and you learn a lot. And have to make excuses to leave 6 hours later...

 

[Jones]

Some of the old-timers were pretty strict. Starting my apprenticeship, my duties were cleaning up and putting away tooling at the end of shift.
I learned later that if I'd reached for the air hose instead of the brush and wiping rag, I would have ended my apprenticeship right then and there.

 

[Jones]

A little more machining done. Making everything out of A76 billet means not having to track down front and rear sheet metal, a pistol trunnion or front and rear sights and bases. More involved set-ups but less hassle in the long run.
The front portion gets a special shaped "Y" piece that doubles as front sight base and the "roof" of the barrel nut catch channel.
The upright "ears" get outside relief cuts to form the crimped top edge stiffeners.

 

[Jones]

With the exception of a few FCG parts, everything is different on the pistols and micros. Even the sheet metal is a different gauge.
Trying to mimic details like the rolled-over stiffener beads on the sight ears involved having special end mills ground and lots of light passes with a collection of 1/8" ball nose end mills. "1/8" carbide cuts good but is sure brittle, especially when cutting deep trenchs).
Got the rear portion almost done and ready to move on to the front.

 

[Jones]

More bits and pieces.
Got the rolled edges on the front and rear sight ears replicated, making them look a little more like the original sheet metal stampings.
More internal small parts ready for final fitting. The front sight base doubles as the "roof" for the barrel nut catch. After machining my own catch, I lucked out and found an original. I hadn't been able to figure out why the tail on the catch was split until I started mocking up the various pieces.
The catch for the pistols and micros is about half as long as one for a full-sized or mini (as is the available room in the front section) and the half split that's not turned up serves as a 'ski' to keep the catch from tipping when depressed.
Pretty clever fix to keep the pistols and micros free of annoying glitches.

 

[Jones]

Made this little tab and pressed it into a 1/8"X1/2"X1/8" deep slot I milled. This and the runner on the barrel nut latch keep the latch from tipping when depressed. It gets TIGed on each end just to be sure.
Front sight base goes in next and gets drilled and tapped for front sight post.
Steps still to go are;
Attach rear section and finish off welds.
Mark with ID marks and ser. no.
Attach front section and finish off welds.
Park and paint.

 

[Jones]

Getting all the small pieces welded into the front section. The rear section is pretty much just an end cap.
Rear end cap TIGed on and etching done, then the front section gets put on.
The idea behind adding the front section after etching, is it's never an unmarked, unregistered firearm.
I know some folks say marking a firearm you build for yourself is unnecessary and a waste of time--
I say so is sitting in the back of a patrol car and trying to explain yourself and your "ghost gun".

 

[Jones]

Getting this thing mocked up to look for last-minute final fitting touches and clean-up before parkerizing and paint.
Finish will have a well-used and weathered look. Pristine examples are impressive but I'm building a shooter, not a museum piece.

 

[ericthered]

Very cool! Are you planning on modifying the trigger guard as well?

 

[Jones]

No eric. I kinda like the first generation look and since I'm not going for rapid fire, or Camp Perry accuracy.

 

[Jones]

Locate and drill the holes for the windage screw then it's ready for parkerizing and paint.
The original front sight post is some kinda extra fine metric thread so I took the easy way out and used an AR front post.
They're #8-36 so finding a tap was fairly easy. Hope nobody notices the discrepancy..
Also accessorizing as I go. Picked up a factory hard case for it this week. The manual is original and suitably aged.

 

[Jones]

Last of the machining and detail work done.
Drilled and tapped for front sight post, drilled for sight post detent.
I'll have to turn the detent and drill it for the spring but that's a 10-minute job
and isn't holding up the rest of the project.

It's All in the Details Department--The factory spot welded the front and rear sight bases in
so I added fake spot welds to keep the factory look.

If all goes according to plan; it'll get parkerized and painted this weekend.

 

[Jones]

Just killing time while the paint cures and hardens so I thought I'd come up with a front sight detent for this project since
the ones for the full-sized and Minis are too big.
Like I've said before; Sometimes Uzi parts are where you find them. In this case, in the nail and screw bins at my local hardware store.

Steps preformed as follows;
Face off and bore end for spring,
Use a parting tool to make the smaller dia. detent tip while supporting the drilled end with the shank of the drill bit, (Machinist's trick #29)
Cut off and it's ready for a dip in the cold blue.

 

[Jones]

Sheet metal parked and painted. Got some fine fitting to do then it's ready to test fire.
Started a little wear and weathering to the finish to get it to match the grip assy but decided to do that last.
I'd like to get it working reliably before I work on its looks.

 

[ericthered]

Very cool!