STEN Build: strictly amateur

Picton

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Hey gang,

Inspired in dual parts by EddieCoyle's recent thread and by sheer boredom, I'm going to try to knock one of these out. Why?

1. I want one.
2. I've always wanted to learn how to weld.
3. I want to be able to speak intelligently on how people make "ghost guns," even though
4. I'll be SBRing this eventually. Figured I should learn about that process, too.

I'm doing the IO closed-bolt design on a parts kit from What A Country, their last Mk II kit. I ordered just three days ago and it's already at my local PO for delivery tomorrow, which I think is pretty damn good during Covid.

I used to do guitar build threads over on TDPRI back in the dark ages before smartphones, so this'll be my first one in awhile. But I've never even come close to doing anything like this before, so you first-timers can follow along and watch me mess up, probably repeatedly.

More to come once the parts kit arrives. So far, I'm sitting on nothing but five STEN mags and a budgeting spreadsheet, which I'm trying not to look at too closely...
 
Rough estimate for complete build minus mags?

Time, or money?

Under $700. Probably around 658. But that's not counting the tax stamp.

Time? It'll be slow. I'm aware that people crank these out in five hours, but a good bit of this will be me, filling time in a leisurely way down in my basement. I plan to dawdle. Plus, I won't be able to order the IO parts for another few weeks, and who knows how long shipping will take?

I'm prepared to build it with a pistol grip if I don't get the Form 1 done in time, then slide the stock on later. I just have no idea how long all this takes, and I'm trying to fund it with "excess" stuff nobody will miss.
 
Parts kit arrived. I'll get some pics posted when I remember to bring my phone down to the basement; I did take a quick look at the parts. They're pretty grimy, but look to be in good shape. The receiver is Elkington & Co, out of Birmingham. The company I bought the kit from mixes whatever they can find from British and Pakistani sources. I'll get more info posted later.
 
That's not a bad looking kit. Milling the dove tail for the front site can suck .

I'm fairly impressed at the condition of the kit. I like old things and patina, so I'm not on a mission to make this thing look factory-fresh at the end of the day. We'll see how I can make the tube and barrel look.

Looking so far as though I might need to buy a new barrel bushing, which I'm fine with ($30ish) if it keeps the front sight fairly intact; I'm going to "mill" the shoulders with a triangular file.
 
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Oy. That front sight.

I'm working on it now. Definitely, I'm going to need that new bushing. I got the ejector ripped out already, straightforwardly:

05 Ejector before.JPG06 Ejector during.JPG07 Ejector after.JPG

You can see in that middle pic how I tried to make a few tentative cuts at the welds on the foresight, hoping I'd be able to tap it out. Big fat nope.
 
Since you already cut it out close to the line, when milling the ejector slot on your tube, be sure to undersize it a little and hand fit your prepared ejector, if it's a really loose fit it will suck to weld.
I'd put the ejector in LAST so you have the bolt in and cocking lever installed so you can center up the ejector for proper clearance.
 
Since you already cut it out close to the line, when milling the ejector slot on your tube, be sure to undersize it a little and hand fit your prepared ejector, if it's a really loose fit it will suck to weld.
I'd put the ejector in LAST so you have the bolt in and cocking lever installed so you can center up the ejector for proper clearance.

Absolutely my plan. Thanks!
 
Wowie! That front sight is a real bugger.

I had hoped I could maybe salvage the barrel bushing and save a few bucks, since the threads were in fine shape. But this was conditional on the front sight coming out with minimal effort… which didn’t happen.

13 Foresight intital cuts.JPG14 Foresight gonna need to get ripped out..JPG15 Foresight coming free....JPG16 Foresight off!.JPG

To a greater extent than I imagined, the art of breaking apart a Sten parts kit is a matter of finding a good set of pliers or vise grips, getting a good stance, and just tearing all the pieces apart!

I should be able to order my Indianapolis Ordnance parts in two weeks, which will be everything I need to get this thing built. Once my welder arrives, that is.
 
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Wowie! That front sight is a real bugger.

I had hoped I could maybe salvage the barrel bushing and save a few bucks, since the threads were in fine shape. But this was conditional on the front sight coming out with minimal effort… which didn’t happen.

View attachment 358165View attachment 358164View attachment 358163View attachment 358162

To a greater extent than I imagined, the art of breaking apart a Sten parts kit is a matter of finding a good set of pliers or vise grips, getting a good stance, and just tearing all the pieces apart!

I should be able to order my Indianapolis Ordnance parts in two weeks, which will be everything I need to get this thing built. Once my welder arrives, that is.

A dental diamond burr in a high speed Dremel tool would work wonders to cut welds clean.
 
Allrighty. I've got some more progress down. Sarco is dragging its feet shipping my barrel, which doesn't matter anyway because I can't even place my IO order for another couple weeks. But meanwhile, I plan to teach myself welding.

I’d read horror stories about removing the remains of the receiver tube from the machined ring at the back of the trigger group, but it was not all that difficult. I started by chopping through the old receiver around where the tabs are. This was not hard; the metal isn’t thick. Take care not to cut into the metal of the trigger group. The front half of the receiver comes off as a part of this process. Well and good.

02 Receiver tabs incision USED.JPG03 Receiver tabs cut USED.JPG04 Front of receiver freed USED.JPG

The back? A little tougher. The ring where the rear sight is needs to be preserved (there must be a term for this part. I think it’s the “receiver housing.” I’ll call it “the ring,” not to be confused with “my precious”). I cut through the weld across the top, and was relieved to find that my kit apparently had no spot welds at the bottom corners. Some also have welds at the back, reinforcing the J-slots, but mine didn’t.

Lucky me. So I started by cutting a slot straight back to the ring, roughly continuing the line made by the torch cut. In this pic, you can see the cut across the top of the receiver tube that took care of the weld there, along with the transverse cut back to the ring. Make certain you don't cut into the ring itself.

08 Transverse cut at rear receiver.JPG

This left the rear of the receiver tube with very little metal connecting the J-slots and my new slot, which I figured I could tear off using a vise-grip and elbow grease.

I figured correctly.

09 Bending rear receiver 1.JPG10 Bending rear receiver 2.jpg11 Pulling out rear receiver.JPG12 Last bit of rear receiver.JPG

Once I found a place where my vise-grips could get purchase, I just sort of peeled the metal of the receiver out of the ring. It went pretty smoothly. I hit the tabs with a grinder on my Dremel, but I’m not sure whether I’ll need to grind it completely away. These 75-year-old welds look good.
 
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Nice job!

Making great progress.

The inside of the "ring" must be free of all the old tube. Clean and deburr it so you don't cut yourself when fitting up to the new tube.

The tabs on the trigger housing stay......just shape them up leaving as much material as you can but neaten it up.
 
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Nice job!

Making great progress.

The inside of the "ring" must be free of all the old tube. Clean and deburr it so you don't cut yourself when fitting up to the new tube.

The tabs on the trigger housing stay......just shape them up leaving as much material as you can but neaten it up.

My initial thought was to completely grind away all traces of the old receiver from the inside of the tabs, but now I see there's no point. As if the resulting infinitesimal misalignment is going to ruin the renowned precision sub-MOA performance the STEN is known for...

I'm very pleased with how everything is going. I can see why people get addicted to this stuff.
 
My initial thought was to completely grind away all traces of the old receiver from the inside of the tabs, but now I see there's no point. As if the resulting infinitesimal misalignment is going to ruin the renowned precision sub-MOA performance the STEN is known for...

I'm very pleased with how everything is going. I can see why people get addicted to this stuff.

You should remove the old tube residue from the inside of the tabs, just leave the tabs with as much material as you can.

I thought you considering grinding them off.....my bad.[slap]

Clean tabs will allow the tube to sit correctly on the fire control group, otherwise it would sit high and possibly affect trigger function.
 
Once I found a place where my vise-grips could get purchase, I just sort of peeled the metal of the receiver out of the ring. It went pretty smoothly. I hit the tabs with a grinder on my Dremel, but I’m not sure whether I’ll need to grind it completely away. These 75-year-old welds look good.

You're lucky. Mine is spot welded in about a dozen places. I'm going to have to grind the whole tube out.
 
You're lucky. Mine is spot welded in about a dozen places. I'm going to have to grind the whole tube out.

Ughhh.

Seems to be complete luck of the draw. My tabs are stuck solid, but my tube is clean as a whistle.
 
My initial thought was to completely grind away all traces of the old receiver from the inside of the tabs, but now I see there's no point. As if the resulting infinitesimal misalignment is going to ruin the renowned precision sub-MOA performance the STEN is known for...

I'm very pleased with how everything is going. I can see why people get addicted to this stuff.
Mine is quite accurate. I use it in carbine matches where 20 yards is probably the max. I let a buddy shoot it and he ignored the close targets and started ringing steel at 100 yards.
 
Aaaaaand that's the last of the parts, ordered.

The parts kit supplier (What A Country) was super-fast; Sarco has been super-slow. We'll see how IO does.
 
Indianapolis Ordnance. They seem to be the market leader in STEN semi conversion kits.

Sarco shipped today. 14 days even.
 
The IO parts ought to be here tomorrow, then I can start this back up for reals. Meanwhile, the Sarco pistol grip I got yesterday is... interesting. Given that it cost less than $20 and I'm only going to use it in case I can't get this Form 1'd in time, I'm not bothered; seems to be made well enough, but it's ginormously wide. Worse, it won't fit into the slot in the back end of the gun because the hook has too much metal.

I'll grind it down and get it to fit, of course, but just thought I'd mention that the dimensions seem to have been figured out by a blind chimpanzee.
 
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