Replace traditional 2-3 bolt lug design with interupted threaded bolt lug design?

D

Don

New member
Can an interupted threaded bolt locking lug design be made and used to replace the traditional 2-3 locking lug design of most BR bolt actions?

Can the interupted thread locking lug design be made to withstand the same rear thrust pressures as a traditional 2-3 lug bolt design?

With an interupted bolt lug thread design could all the extraction and timing issues of a traditional 2-3 lug design be eliminated and simply replaced by the thread pitch rotation of the interupted bolt lug movement?.............Don
 
Don, I think that is what you hae with something like the Winchester M88 and M100 bolts and the old Lee Straight pull. The thread would probably need to be something like a 55 degree Acme or a Buttress style, if not even steeper than 55 degrees.
 
Don

Good idea

I would think it could. I believe I saw a rifle at The Shot Show that works that way. My concern is dealing with the torque applied to the bolt when fired. Two angled surfaces on the lugs may not work well with high pressure rounds. With the equipment we have these days the working surface of a lug either in the action or on the bolt don't have to be a straight line. Also not all the lugs need to function in the extraction phase of this. Think about that.

Dave
 
Thread for recoil

If I were going to do such a thing, I think I would look at a Dardelet thread. They are designed to lock. Also a Buttress thread will take high stress such in a punch press.
 
Don,
The 1917 Enfield has angled bolt engagement surfaces. Can you imagine what would be involved in truing up the mating surfaces of the action and the lugs? I don't think that there is an advantage to the system for what we do. All that interrupted threads would do is to reduce the unit loading that produces galling, and this has not been a particular problem with good material selection, hardness differential, and a little grease. Not to rain on your parade entirely, thinking out of the box is a good thing. That is how we move forward. :)

Added post AM shower
I got part of the above wrong, and will elaborate later...off to work
 
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Ive been thinking about the same thing for some time, the only possible issues I can think of, as already mentioned by Dave, is bolt thrust, and headspace. If for some reason the bolt handle is not fully closed youve just increased headspace=not good, and is the bolt going to try to 'unscrew' when fired? a couple of possible suggestions is to have a spring loaded detent going through the action wall of the tang into a dimple on the back of the bolt handle to hold the bolt in the locked position, or one magnet on the underside of the bolt handle and one in the action where the handle stops, it all depends on the rearward thrust of the bolt and what force is needed to hold it in situ, if any? The benefits of helical lugs would mean the camming action is taking place throughout the 90 degrees of bolt rotation as opposed to 5-15degrees? of orthodox actions, its got to be smoother which means less disruption on the bags, and also the bearing surfaces of the bolt lugs and lug abbutments is increased all be it marginally.

KB
 
Pete Pieper in Hempstead, Tx has a buddy that did that with an aluminum receiver. I am almost sure that the lugs were hard anodized aluminum. I'll have to ask Pete.
Butch
 
Thread

A friend of ours up in this neck of the woods (won't mention his name) quite a few years ago, built an action using an interuped buttress thread. He chambered in a 6mm rem and used it as his
reach out and touch em prairie dog gun.
I shot this gun a few years back, and it performed very well.
He mentioned he has had no bolt set back after several thousand
rounds
y.h.s.
Mark b.
 
Don, my Engineering Department just informed be this has been done before in the old Webber BR action,and likewise the Newton action.
 
JerrySharrett said:
the Newton action.
Click to expand...
Sho nuff!

book_cover2.jpg
 
K Battenbough said:
If for some reason the bolt handle is not fully closed youve just increased headspace=not good
Click to expand...

Should not be a problem as the cocking cam/firing pin cocking piece prevent the firing of the rifle, or firing pin from moving forward unless the bolt is fully cammed in the firing position........our present cocking cam, trigger release design.

K Battenbough said:
The benefits of helical lugs would mean the camming action is taking place throughout the 90 degrees of bolt rotation as opposed to 5-15degrees? of orthodox actions, its got to be smoother which means less disruption on the bags, and also the bearing surfaces of the bolt lugs and lug abbutments is increased all be it marginally.
Click to expand...

My feelings exactly!

Also, the threaded extraction camming surface area will be tremendously increased over the tiny surface area used by the present bolt handle to action camming surface angle cut............and most importantly the threaded extraction camming surface will be symmetrical as opposed to offset with the bolt handle method...............Don
 
John Kielly said:
Sho nuff!

book_cover2.jpg
Click to expand...


Very interesting, although my vision was the use of a "full diameter" threaded locking lug that was no larger in diameter than the bolt body, thereby eliminating the need for any action "raceway" cutouts, better/less costly ease of manufacturing.

In the case of a Remington 700 style bolt/action, simply thread the bolt nose with a 1.0" long x .700" dia. x 5 tpi o.d. threaded locking lug area, same with action housing i.d. area, all precisely in axial alignment, and complete by milling (2) 90 degree interuption cuts to both bolt and action threads.

Forget all the action "raceway" e.d.m./broach cut and internal lug developement machine work, forget all the bolt rectangular lug protrusions and vertical surface mating/machine work.

I am surprised and delighted to see that Newton used a "coned bolt/barrel face" setup. When was this particular Newton rifle designed/manufactured?

Boy those double set triggers were sure complicated, wonder what those double sets could do that our simple single stage Jewells can't?......................Don
 
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Don

Don, I'm no machinist, but it seems like a bolt could be built, and a threaded bushing installed in an existing action to test the setup? Or are there a bunch of things I'm not seeing?
Bryan
 
Newton

Newton manufactured his rifles from 1916 to 1919. What you are talking about doing with full diameter bolt is similar to the Weatherby MK V action.

Todd
 
Keppler & Fritz in Fichtenburg Germany made some target and snipping rifles on their own action. The bolt design looks quite similar to the Newton in my photo copy .

There is an article on these rifles in the April 98 "Tactical Shooter" magazine starting on page 11.

I have a copy of "The Newton Rifle" and it's an interesting book well written.

Glenn:D
 
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The 1910 Ross had the "interrupted thread" design. Here are a couple of photos of my 1910 Ross 280 sporter.

Ross1910copy.jpg


Ross-1910copy.jpg


This is my 1905 Ross 303 military model. Note the solid lug in the vertical position (the 1910 lugs are horizontal when not in battery). Also visible is the fact that the lugs are angled on the locking surfaces.

Ross1905copy2.jpg


The Ross rifles were known for excellent accuracy, and used as target rifles at the time. My 280, even with iron sights, will keep three shots inside one inch at a hundred yards.


Jim
 
ACArms said:
Newton manufactured his rifles from 1916 to 1919. What you are talking about doing with full diameter bolt is similar to the Weatherby MK V action.

Todd
Click to expand...


I've wondered about the Weatherby lug design, but the ones that I have seen do not look like a continuos thread pitch cut developement with interupted cuts.

The multiple Weatherby bolt lugs look almost individually pattern milled to match same i.d. of action lugs...............Don
 
Thanks John and Jim for the very nice samples of angled action lug designs................Don
 
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