Aluminum Dummy/Replica Receiver "press fit" receiver for barre

[Kocapuff1]

All,

 

I have two nice 1928A1 replica/dummy aluminum receivers I want to build my two replicas as a early style production 1928A1 style with fined barrel/Lyman sight and on the other the late production 1928A1 with smooth barrel/cuts with the "L" Lyman sight.

 

The aluminum replica receivers have nice markings and everything, but have "press fit" area for the barrel...... Does someone have the ability to tap the receivers for the barrel thread? Where do I buy a proper Tap so the barrel would tap in?

 

The press fit seems awfully tight to tap the barrel in.... Has anyone on the forum used these press fit type receivers and tapped the barrel into the press fit?

 

Any help greatly appreciated. Have a nice night.

 

[Paladin601]

you can't tap it, different thread tips. Thompson barrels have square threads (acme threads) taps are Unified (UNC/F).. Acme are cut with a single point tool.

 

If the barrel will fit into the receiver, you may be able to hold in, securely with a set screw. Or bore the receiver to accept the barrel as a press fit.

 

Press pit is not with a hammer, but Hydraulic press, or Arbor press

Edited January 27, 2015 by Paladin601

[ron_brock]

Only way to thread it will be with a lathe. The thread is a squared off thread, I believe an acme thread off the top of my head but don't quote me on that without checking the specs.

 

You're best bet is to press it in. You're lucky to have a press fit as the aluminum receiver I had was oversized.

 

Ron

[timkel]

There is not enough metal there to tap for your barrel. For a press fit just use a piece of 3/8" all thread. I just built one of those. Pressing in the barrel was a 15 min job.

Edited January 27, 2015 by timkel

[reconbob]

The square thread of the Thompson is different from an Acme thread which is an

angled load bearing thread usually found on machinery. The square thread was used on

U.S. Military barrels such as Thompson, Springfield, Garand, M1917', M-14' etc. but

other than these I have never seen it used for anything else, so no taps to generate

This thread are available.

You could single point it in a lathe, but your best best is probably to contrive to

press it into the receiver. This is tricky because the grip mount is going to push

against the barrel while you are trying to seat it straight. Also if the barrel has a

sight you have to make sure it's positioned correctly.

Being soft aluminum you may not get too many tries because after a couple

of fits the bore will wear and the barrel will then be loose.

 

Bob

[buzz]

here's a suggestion

 

sand the hole for the barrel with very fine grit paper until you can assemble the barrel and receiver by hand pressure

 

then coat the threads and hole with clear silicone kitchen/bath caulk

 

assemble the barrel and receiver and spin the barrel until the front sight lines up just so

 

if the silicone isn't a strong enough bond for you, use hot glue

 

if you use hot glue, the glue could be melted just by leaving the gun on your dashboard on a hot day

 

I'm just trying to think of something that would hold the barrel well enough for display and handling but not be so firm that you couldn't disassemble or adjust it

Edited January 27, 2015 by buzz

[laurencen]

same here as Buzz said, take a piece of wooden dowel a bit smaller than the hole in receiver, cut a slot with a saw to allow a strip of fine grit cloth to wrap a couple turns and lap the hole until its a snug hand push, assemble using Loctite and remember to line up sight

[Kocapuff1]

Thank you for all the input. I'll stick with the press fit of course, since there is no other option. I'll probably sand some and then find a hydraulic press to push the barrel into the dummy receivers. Great information from everyone. Have a good day.

[richard w.]

I've worked on two of these.

 

The first was a dummy build for myself. Barrel was sized for a perfect press fit but I had a devil of a time rigging it into my 12 ton press. The way the receiver is shaped, it's very hard to apply pressure straight down into the barrel hole. Kept wanting to twist on me so I wound up hammering it in with a piece of wood and a 3 lb. drilling hammer.

 

I would never have done that with good, live barrel parts, though. My barrel has a big bulge in it and the Cutts has had it's threads destroyed through improper removal, so I didn't mind hammering on it.

 

The second receiver I own had a good barrel half installed into it, and I wanted to remove it. Discovered that I could unscrew it out by clamping the barrel in a vise and wrenching on the receiver nose. Unscrewed great. If I assemble another I will get the barrel started in the hole and then screw it in. I'm pretty sure the steel will have no trouble making it's own shallow threads if I turn it hard enough.

 

The aluminum receivers are nice. Not Philly Ord or DR nice, of course, but good for a knockaround dummy. here's mine. It's heavy. 9 lbs. And 11 oz. Almost as heavy as a real one.

 

http://www.fototime.com/A9A35ADCE056C8E/xlarge.jpg

Edited January 27, 2015 by richard w.

[Paladin601]

Very nice Rich,

[Paladin601]

My mistake, not Acme threads but "Square threads" thanks Bob

[Kocapuff1]

I've worked on two of these.

 

The first was a dummy build for myself. Barrel was sized for a perfect press fit but I had a devil of a time rigging it into my 12 ton press. The way the receiver is shaped, it's very hard to apply pressure straight down into the barrel hole. Kept wanting to twist on me so I wound up hammering it in with a piece of wood and a 3 lb. drilling hammer.

 

I would never have done that with good, live barrel parts, though. My barrel has a big bulge in it and the Cutts has had it's threads destroyed through improper removal, so I didn't mind hammering on it.

 

The second receiver I own had a good barrel half installed into it, and I wanted to remove it. Discovered that I could unscrew it out by clamping the barrel in a vise and wrenching on the receiver nose. Unscrewed great. If I assemble another I will get the barrel started in the hole and then screw it in. I'm pretty sure the steel will have no trouble making it's own shallow threads if I turn it hard enough.

 

The aluminum receivers are nice. Not Philly Ord or DR nice, of course, but good for a knockaround dummy. here's mine. It's heavy. 9 lbs. And 11 oz. Almost as heavy as a real one.

 

http://www.fototime.com/A9A35ADCE056C8E/xlarge.jpg

 

That is the same (yours in the picture) as my two aluminum receivers I have for making mine!

[richard w.]

Grab some replica slings from What Price Glory. they are super and complete a Thompson.

[Z3BigDaddy]

The three I have done I used a five pound press attached to a wooden handle. Worked for me.

[Kocapuff1]

Thank you all for the information. I'm sure it will help others also in the future. I have a M1A1 Dummy Aluminium receiver also now, (Thank you Gutteratt), for my M1A1 Savage Dummy/replica, that I also plan to build in the near future. I am in need a of finned original 1928A1 barrel that is shot out/worn out that I could get a low cost from someone to put on the 1928A1 early model build replica/dummy. So if someone has one let me know. I think I'll try the screwing the receiver onto the barrel slowly in the vice trick first, if that doesen't I'll have to try to find a press to try. I'm also in need of M1 front sight pin, and Cutts Comp front sight pin.

Have a great day gentleman!