Sten Mark III carbine build

[1911ly]

It's time for a lone needed update. I got seriously side tracked!

I finally got around to machining the receiver tube. I am not a machinist but I can make some chips with the mini mill. Mine is a Harbor Freight 3:1 machine. Lathe, Mill and Drill press. It does really well if you know it's limits. I can't make fast deep cuts. Slow and steady wins the race.

First things first. make sure the Vise is square on the table. My cheaters way is to use a 1-2-3 block. I put it between the lathe chuck mounting plate and the edge of the vice. I double check it with the dial indicator and it's GTG.



The handiest thing I have on the mill is the DRO. OMG does it make life easy. It's probably worthy of a thread in it's self but I will keep it short. It's a set of Igaging scales interfaced to a MSP430 Micro processor development board. The MSP430 is hooked to a Blutooth transmitter and it send the measurements to my Adroid device. In this case it's my Note III. I have a 9 inch tablet I should be using but I was to lazy to calibrate it. Anyway. Here is the DRO:

It's in a sealed plastic box. And yep. I wired it. I am a geek!


The display:


I drill holes in the corners to mark things just in case the template falls off and it usually does at some point. Then basically play connect the dot's. I write down the measurements on the DRO when I am in the corners of the cuts. It makes it easy to repeat the cuts. I cut in about 5-10 thousands at a time until I am threw the metal. Any faster and things don't work out so well.








OK. the cuts are made. Here are a few pics of the tube with the template off. BTW, Wet the thing down with WD40 and let it soak for a bit and the template comes off easy:





Here's a few pics of the test fit of the mag well and the trigger guard assembly.





I need to weld on the hand guard and install the barrel. I am going to make the barrel removable. So I have some drilling and tapping to do on the trunnions. Then do the finish coat.

Hopefully it will be a shooter by the end of the week. Weather is going to be the key. I have to weld out side. More to come and sorry about the slow update!

 

[freekforge]

Awesome! looks like your DRO was worth the work. Are you cutting a shoulder or something for the locate the barrel in the same spot after removal and installation? I know nothing about stens so that may be a dumb question.

 

[1911ly]

The barrel doesn't need to be indexed in anyway. It is sandwiched between the (two) trunnions. I will mill a flat spot and use a set screw to keep it from rotating. I'll take picks when I get that far.

Hows your projects going Ethan?

 

[Trigger Time]

Man your making me want one even worse now!! That's a pretty awesome setup you have!! Now that the polish ak build is done I need another project. No more AK's for a while though. It stressed me out lol.

 

[1911ly]

I still need to finish my AK's I have a road block at the rail welding. I dropped a slight hint to the Thewabbit about welding my rails... :-) Don't thing I hinted hard enough. Lol. I need to hit him up. See if he has some free time. I can make a road trip.

Everyone should build at least one Sten! they are fun. And very doable with a Dremel tool. Especially if you build the Mark II. They are easier.

 

[freekforge]

Intersting looking forward to more updates.

Well I have always said i'll never do production work and then life said "yes you will" the bowfishing points really took off.

 

[1911ly]

Intersting looking forward to more updates.

Well I have always said i'll never do production work and then life said "yes you will" the bowfishing points really took off.

That's awesome!!! Nothing wrong with that at all!

 

[1911ly]

I am on a bit of a roll lately. I welded the hand guard/trigger well and mag well on this afternoon. The mag well was a PIA. It was slightly bent and the tabs were to short and the front edge was cut in to when they demilled it. The tabs on the hand guard were cut short too. But it's fine for me. I am not building a show gun.







I will probably put the rear trunnion in yet tonight. I have to weld up the spring guide rod and install the barrel and front trunnion. Then it should be a shooter!

 

[Airborne18th]

You make it look too easy. Those stens are iconic. I think it looks great. Maybe I should take the plunge. Awesome job on digitalizing the mill.

 

[1911ly]

If you do you are welcome to mill the tube on my mill! I am going to to a mark V next.

I had a set back today. I riveted the rear trunnion and did not realize how long they are. The barrel should have been in the gun when I riveted. It wont fit now. Plus I am nothappy about the rivets hitting the barrel. I am going to drill them out and use button head screws.

So close to being done!!!

 

[1911ly]

I had time to get back to the Sten project yesterday.

I installed the reaar trunnion. I opted for a screw build. I used 8-32 allen heads. I will swap them for button head screws. The hardware store was out of them at the moment :-( these will do:



The front trunnion was not made very neatly. It was war time and I am sure they make these for use and not beauty. I neatened it up on the lathe and polished it:



Cleaned up:


I installed the barrel and front trunnion. Well things did not go so well. I had some trouble shooting to do :-( I went to cycle the bolt to make sure it would chamber rounds. And it would feed rounds but not extract rounds. I thought maybe I had the magwell welded misaligned. I it turned out to be the barrel chamber. It was cut to deep. The round loads fine in to the chamber but it should seat and allow the extractor to ride over the rim on the cartrage. Instead the round goes in to far for the extractor to jump over the rim. It took a while to figure this out. I confirmed it was the issue by measuring the chamber depth. Below is a pic of two barrels with a round in them. It's kind of obvious when you compare the two. It's about .050 thousands to deep:



This barrel is not from Indianapolis Ordnance. They we out of stock at the time I ordered this barrel. I have been in contact with the barrel maker and they are going to cut me another barrel. So I have a delay in my build for a week or two! Oh well. Crap happens. I am happy they are taking care of the barrel.

More updates to come soon.

 

[1911ly]

I found this video on another website today. It provides some history on the Sten gun. I hope you enjoy it.

[video=youtube;NMqSsvqjJ2E]https://www.youtube.com/watch?feature=player_embedded&v=NMqSsvqjJ2E[/video]

 

[freekforge]

I think it kinda looks cool with the allen head cap screws but im weird like that

 

[1911ly]

I think it kinda looks cool with the allen head cap screws but im weird like that

The caps do have that industrial look!! lol. They don't look to bad. The buttons just look more like the rivets. I am in no hurry to replace them!

I am tempted to turn that barrel in my lathe. It's just that my chuck sucks! It's about .005 out of round. Cheap chuck. I am really tempted to buy a new one. Plust also doesn't feel right when I tighten it down. Kind of crunchy feeling. I took it apart and the drive gear is really **** poor machined and worn. This lathe is probably 10 years or so old and I don't know the history of the chuck. I think someone overly aggressively tightened things in it. The chuck is the only questionable thing left on the lathe. Hell I am gonna order one!! Gitter dunn! I want to shoot. I can have it in by the middle of the week.

Hope all is well with you FF my friend! How are your projects? BTW, I still need to back base's for my mortar :-( Another project!

 

[freekforge]

having a good chuck can make a world of difference.

I have never made so many of one thing the fish points are going like crazy. unfortunately we have had another death in the family so i have been spending time with my mom and helping out when i can so the machining is on the back burner for a few days.

 

[1911ly]

having a good chuck can make a world of difference.

I have never made so many of one thing the fish points are going like crazy. unfortunately we have had another death in the family so I have been spending time with my mom and helping out when i can so the machining is on the back burner for a few days.

I am so sorry to hear about the death. The older you get the more ofter it will happen. It sucks!

I got anxious and spun the barrel with what I had. I ended up shimming the jaws to get it round using strips of aluminum foil. I was within a half a thousands when I got done. I had to grind a tip special tip to do the feed cone. It was a PIA to get in there. It all came out well. I got the trunnion rotated, re-drilled and tapped.

I put it together and put 3 rounds threw it. It ran great. no issues. I will have to put some more threw it. Tomorrow I will clean it up a bit and take a few pics. Probably put a few more rounds threw it too.

I now have two Sten's and they both need paint! I have 2 or 3 more to build. A Mark V is next! I think anyway.