I just picked up my new bighorn origin short action for a build . I am planning on doing this barrel myself I did my first one last year was really fun and would like to do it some more. My question is I had them send me a tennon print my measurements match spot on but would I be ok with a thread relief at the shoulder. It has a pinned recoil lug which on like a Remington style I’ve seen tennons with a unthreaded area for the lug, but doesn’t seem the print calls for one. I could put a savage barrel on it which is straight threads under the lug which makes me think I would be ok with threads up to a relief at the shoulder just want to get expert opinion before I start on it down the road.
Bighorn origin tennon
- Thread starter Toptom
- Start date
(flame-suit on)
My mentor always told me that if it wasn't called out on the print, it was wrong. That said, most gunsmiths will tell you that a relief groove is not going to reduce strength enough to cause any unsafe condition and there are plenty that do it that way.
If you fancy yourself as a machinist, do it to the print. If you consider yourself just a gun plumber, then do whatever works.
My mentor always told me that if it wasn't called out on the print, it was wrong. That said, most gunsmiths will tell you that a relief groove is not going to reduce strength enough to cause any unsafe condition and there are plenty that do it that way.
If you fancy yourself as a machinist, do it to the print. If you consider yourself just a gun plumber, then do whatever works.
I do have machinist background kinda how I got into playing with barrels always been on my bucket list I’ve always loved anything to do with guns. but with the print I can’t tell if there showing to the shoulder or a relief it actually sorta looks like it shows a relief. Just this is my first one with a pinned lug my first try on a barrel was for a push feed 70 which was a intergal lug and was probably the most simple tennon I could think of for a first try.
Really no issue either way. If you are more comfortable using a thread relief, then go for it! There really is no wrong way to do this job.
Paul
Paul
DaveTooley
Gold $$ Contributor
I've chambered thousands of barrels with a 3MM wide thread relief groove. 27MM and 30MM diameter threads. No problem. Just a different way to skin a cat.
DaveTooley
Gold $$ Contributor
Yes it does.
Do you recommend a unthreaded area for the pinned lug to set on or just threads the whole way say to the shoulder or The thread relief if the person uses a relief. Idk if it would make a big difference or not, I know you guys on here would know if it shows any difference at all in overall accuracy.
DaveTooley
Gold $$ Contributor
With a lyg you have a pretty wide area to end the threads so I would've put a groove in. I will offer this advice. On your last pass turning the tenon to diameter run your tool deeper into the tenon by .030" or so. That guarantees the lug won't touch the radius left by the tool.
I’m going to send you a pm with my overall idea to see if it seems right if you don’t mind.
DaveTooley
Gold $$ Contributor
I don't mind but I'm packing for the trip home to NC from TX. I read your PM and you're over thinking this. After the first few passes you'll have no problem retracting the threading tool in the same place. Position the knob on the cross feed at 12 O'clock and on zero. All it takes a quick flip of the wrist with your thumb and the tool is retracted. Disengage the feed at the same time. Practice a couple of dry passes using the shoulder as a reference.
On the road again.
On the road again.
Is there any certain width to keep the flat area for the lug or how thin it could be as a rule of thumb. If I put one on this with a relief it would be a small flat area for the lug. Seems more I research some guys have had a flat area some don’t use them.
WSnyder
Silver $$ Contributor
I use a flat under the lug and a thread relief for most. I’d say the flat is 80-90% the width of the lug and then a .050” wide or less thread relief overlapping the edge of the lug. Once upon a time didn’t use a thread relief but that was just pride/ego to prove I could do it. I decided at some point to make life easier and use a relief. I cut the relief with my threading tool. Plunge to depth and cut to desired width. Saves a tool change. I also undercut the shoulder just at the junction of the tenon/shoulder as Tooley recommends, it’ll potentially save you some grief if you have a non chamfered lug.
DaveTooley
Gold $$ Contributor
Just got done driving 560 miles today. I believe your lug has a single pin so you can fit the cylinder section closer to the ID of the lug. But and a big but, you need to verify the lug floats freely when the action is run up hand tight. Everything has it's nature resting place.
Did you do a 60° on the entrance to the chamber on that Origin barrel?
Judd
Gold $$ Contributor
I cut a relief groove on mine, just inside the back side of the recoil lug. I did cut the relief at the shoulder Mr Tooley mentioned right after this picture was taken. I’m probably the rookiest (yes, I made that word up) on the fellas posting on this thread so don’t take my word over theirs. After this post though and seeing some of the other pictures posted…I’m going to play with not cutting a groove and see how it goes.
I had been thinking about doing that anyway because I made an extension to put on barrel tenons so I could do shorter (< 22”) barrels thru my headstock and didn’t cut a relief groove for internal threads (I was home and had that tool on order but hadn’t been delivered yet) and it looks good just stopping with a indicator on the carriage. Thanks this post solidified my thinking…that more than likely I didn’t need that groove and it would still look presentable.
Oh and if you guys that really know what you’re doing see something you don’t like, feel free to constructively criticize. I’m very much still in sponge mode and sucking up all the information and feedback I can. Stuff thus far has shot decent to holy crap so I am happy but know I’m always going to be learning…I’m one of those self taught guys with mentors that help on a phone call or IM on a forum. I bought this lathe 3 years ago and didn’t even know how to turn it on
Bataction
Gold $$ Contributor
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