The Yukon 2 is a beast of a 58 caliber. After a whoooooole bunch of lead downrange, the bolt started sticking. Julio and myself, kicked around what may be the cause. Then; I told him how to remove the top end of the rifle and ship it to me.

When I tore it down, nothing was damaged. The only thing I found was a machined delrin breech seal that was grabbing the bolt nose very tightly. However; I noticed that the barrel retention grubs, were putting pressure against their machined sockets. There was a slight swell on the pressure end of the four machine grubs. Was this allowing that machined seal ring to have enough play to create a sticking point? Cause, when it stuck, it really stuck.

Well, after staring at it from all angles. Downing a pot of coffee. Sneaking up on it for a second look. I decided to retro the whole dang thing.

I'd thread the barrel into the receiver - as I've come to do - as one of those "no pay" changes I've tossed into the builds of all guns. There's always something else that could be done. Designing is going far enough to create a really fine product that does the job and lasts well ... beyond that, you are just driving yourself out of the last dime of profit. But - this seemed the place to start on this job ... to take any barrel drift off the table forever.

Now ... the cute part .... you have a .750" barrel stub in a .750" receiver socket. Hummmm ... gonna be some REAL fine threads. hahaha. I needed a sleeve. Nothing simple. The sleeve had to go between the barrel and receiver. Had to not compromise the barrel. Not compromise the receiver. Had to have threade inside and outside. The barrel outside had to be threaded. The receiver had to be threaded inside.

Now ... threads obviously interlock. So, you need to learn what size to make the male and female parts, so that when threads are cut on both - they interlock tightly. Might sound simple ... but it's a handful to keep your mind around. Especially because .... the barrel, sleeve, and receiver also have to allow for the fact that the "tang" of the barrel is not fully threaded for 2 1/2 inches, or it would be absurd to wind things into place with the fine threads used.

I used about 1/2" length of threads, which is still about 16 threads on this project. That means the rest of the tang is smaller and smooth. It fits inside a cavity which is small in the back, and then larger and threaded in the front.



Well, here are the parts. Barrel threaded outside, and threade inside the sleeve (where you cannot see the threads). Outside of the sleeve is threaded to mate with the inside of the aluminum bronze receiver (where you can't see the threads).



And, here it is all threaded together. Feels like focusing a nice scope! The threads are much better than required. ;?) And now, I get to change the way the bolt nose seals. Rechamber the barrel for the 1/2" alteration in tang length. And, tidy up the barrel's burl finish.

Thought you'd like to see a little head banger of a retrofit to keep this fine rifle in the field.



Gary

There folks is just one more chapter in an ongoing saga of the "Life of an Airgun Smith" .

Great fix on that one Gary, I appreciate the look. What was that, like 8 set ups to complete that can't see it now that it's done fix. No one but the people who read this post will ever appreciate just what went into mounting that barrel, and I guess that is the mark of a master smith for good or bad.

gary , thats as nice a bit of work as ive seen you turn out , well done again , have you ever heard of jb weld ,,,,lol
ill get my coat




leaving now





gone

Gary,

Were those cut on a lathe or die?

Lon

Lathe.

I hear single point threading on a lathe is VERY difficult, single point threading that actually fits is almost impossible and single point threading that fits AND works is a myth.

You could make Swiss watches!

I'll guess 2 hours to complete that project ONLY because you are setup and experienced.

Lon

BTW, have you ever tried an epoxy called JB Weld, it's great for stuff like this and a real time saver.



Edited 3 time(s). Last edit at 11/28/2010 02:29PM by Bigbore.

Lon,

Gosh .... I didn't know it was impossible! No wonder it requires thought ... hahhaa.

Gary

Very nice fix Gary.

I too didn't know that single point thread was near impossible to cut on a lathe? Metric thread is more difficult on some older lathes are you cannot disengage the carriage once threading is started.

My dad had his own shop when I was growing up and I watched him cut lots of thread. I was 12 at the time and I asked him if I could try. 3/4 - 10 was the first thread I ever cut and I did it all alone as I wanted to show him I could, haha (boasting).

Pedro

I think it is a 60 degree tool at 29 degree angle, and if i remember alot of tool back pressure. db.