Tightening a barrel
 

I just got a Navy barrel for a project I'm working on, so I read postino's excellent tutorial to prepare myself for the installation. One thing that worries me a bit is that the barrel can't be hand tightened to the 1/8 turn described as "just right" in the tutorial. There's a little less than a 1/4 turn left, so do I need to trim the flange or just lean on the wrench and use my extensive vocabulary?

I don't think it would be too difficult to trim it, but from what I gather, the flange surface on these barrels should be slightly tapered to give it some "crunch". Does anybody know how many degrees of taper it needs?

People actually read that??? :eek:

You could lap it in...I've used Rubbing Compound, or Polishing Compound (one is coarser than the other) to lap a barrel in that was 'almost' right...Clean dry threads, put the compound on, tighten & loosen a couple times, take it apart, clean it, put a dab of grease on the threads, and see how close it comes then...repeat as needed... :thumbup:

But that's just my way...there's lots of ways...even some right ways... :D

Well, I did look at the pictures. :D

That sounds way easier than turning it! I think I'll try and tighten it a bit with the wrench first, the surface still has some machine marks so they'll probably give me a few degrees as well. Thanks for the tip, I have that nagging feeling that I'll take off too much if I turn it... :eek:

Exactly so! :thumbup:

The Rubbing Compound is coarser than the Polishing Compound...And if you really want to remove metal, Valve Grinding Compound takes off a lot of metal in a hurry (use with caution...I wouldn't use it here)... :)

I have some different grit compounds I use for lapping scope rings, and if the going gets tough there's some valve lapping compound back in a drawer... That, a few beers and a large pipe wrench should do it! :D

If not try a larger wrench and more beers!

I think we can all agree that the proper tools are essential for any aspiring gunsmith... :thumbup:

Just keep in mind the old adage;

"A gunsmith's best friend is a home gunsmith"

That's probably the reason why I was able to buy this project gun for $300. It looked like the home gunsmith actually did use the BFH to take it apart... :rolleyes:

:cheers:I like the 2nd one from the right!!!! That is George Fortier's favorite gunsmithing tool!!!!:roflmao:

Hugh..I have to disagree..George wouldn't use a BRASS hammer! Or one that small...

:thumbsup::cheers::thumbup::roflmao:

Did you tried frozen state installation? It may give you just enough what is needed to time it right.
After barrel expands again it will be solidly married especially if you use proper bounding agent.
Try only barrel not slide. Liquid Nitrogen is your best friend.

terminology....sp.???
 

Hi Guys, we need to get on the same page on one item of barrel installation... 1/8 of a turn... by degrees, is considerably different the 1/8" inch of rotation on the circumference.... if the edge of the extractor relief of the barrel is close to the extractor relief on the receiver... just prior to lining up, (just visible)... it's going to get tight fast!!! If it is 1/8 of a turn of a rotation, or more, it is going to be too tight!!!!!... or at least close to the end of what ever crush rate is figured in the flange undercut... tough to hold everything when it gets to that point... best to all, til...lat'r....GT:cheers:

Ok, now I'm getting confused.... So if I can hand tighten it until I'm 1/8 turn from 12 o'clock I'll be alright, and I can do the rest with the wrench? Or how does the 1/8" come into play? It's Saturday evening and I have had a few glasses of wine, so please explain in simple terms. :p

last 1/4" ....
 

Hi to all, Rich has certainly been there and done that...:thumbup: with excellent success I might add... He knows that last 1/4" inch can seem like a mile when you can't hold things tight enough!! ...:eek:... I'm still learning, and it's great to have other forum members to bounce ideas and thoughts off of!.....:cheers:... best to all, til...lat'r...GT

I have been trying to figure out how this would affect the installation. Seems like freezing the barrel would actually defeat the purpose, as it will reduce the distance from the shoulder to the thread, and it may also affect the pitch of the screw. I know that freezing works great on press fitted parts, but I'm still not sure how it would work on threaded parts. Have you tried this method?

Olle, dont forget to check the headspace when your done. If you dont have a gauge, you can always turn out a gauge on your lathe.
John

John,

I was planning to buy the gauges, quite honestly I didn't even think about making my own. I'll look into that. :thumbup:

anti seize...
 

Hi Rick, great tutorial! I've not used the anti-seize, but will start... I'm thinking about making a hardened receiver thread fixture, and a hardened barrel thread, with the class fit you mentioned... just for a benchmark when checking out parts for compatibility... :thumbup:,... again, great thread! best to you Rick, til...lat'r....GT:cheers:

I've had good experience with Neverseize, but it does have one annoying side effect. One very small dab of the stuff will cover half of the free world. Have you ever had the experience where you apply a small amount and notice shortly thereafter that your face is coated with the stuff, as well as your hands and clothes? Nothing like that healthy silver glow.......... Of course, you could use Felpro if you want a golden hue.

Been there, done that. I still remember first time I used Copaslip on the exhaust manifold bolts in my Camaro, I didn't know how much (or actually how little) I should use and ended up with a mess beyond belief in my neatly detailed engine bay. Same thing when you use graphite grease, you wipe the sweat off your face a couple of times and you end up looking like Gene Simmons. They say that a little goes a long way, and it obviously means that it migrates a long way from the place you used it. :rolleyes:

I thought that I was the only one that could manage to get that stuff nearly everywhere when starting out with such a small amount........maybe it multiples once it leaves the tube!!

"I thought that I was the only one that could manage to get that stuff nearly everywhere when starting out with such a small amount........maybe it multiples once it leaves the tube!!"

I think you are on to something there rhuff.

Can'o'worms!
 

The old adage is: When you open a can of worms, you always need twice as big of can to get them all back in!" So it is with the barrel tightening task... But, I have since discovered, it is friction, holding, and torque, turning... and not much else enters in... the undercut on the barrel flange, is most likely there to flatten out the torque needed to index the barrel properly... Meaning, if you can hold the barrel, without scratching it, and turn the receiver without distorting it... you have a range the it will tighten in to the proper indexing position... We know where it starts, approximately??... where this range ends, is, as of yet, not known to me, as I can't afford to go to the yield point on my dollar....i.e. receivers aren't growing on trees! :jumper:... all the previous info on this thread is important, and definitely points the way to successful installations... we get better as we go... best to all, til....lat'r....GT:cheers:

I'm sure the first couple dozen are a real learning experience, G. T...

dju

More Barrrel Info....
 

I replace barrels on Lugers on a regular basis....In Canada a 110 mm Barrel on a Luger makes it legal to own for most people whereas a 100 mm(4") Luger is considered a prohibited Firearm.....I work in conjunction with a machine shop and we make the barrels from scratch from rifled 9mm blanks....The best way we have found for proper indexing is to use an old receiver(as a guide),machine the threads and tighten up the barrel to the receiver....make a witness mark at he bottom of the barrel....remove the barrel and then machine the front sight 180 Degrees from the witness mark....the barrel will then install with the correct tension and vertical alignment.......Attached are some photos....

Impressive work!
 

Very nicely done! One question, how tight do you tighten the blanks in before you index?? Do you have a definite final torque spec.?? Maybe two questions.. how much does it set you back to make the barrel?? Looks like top quality work, very impressive... best to you, til...lat'r....GT:cheers: