Jackie's pics
- Thread starter Geramo
- Start date
jackie schmidt
New member
Promised Pictures from Previous Discussion.
In the thread "thismay be a silly question" downstream, we got into the discussion of the actual strength of a thread, mainly my idea of establishing a 16 tpi, (threads per inch), over an 18 tpi, so you could use a take off Panda or Viper barrel in a Remington Action. I made up some parts to test the strength of my "16 tpi over a 18 tpi, since there was a question of safety.
The shorter dark piece of bar stock is the 4140 commercial heat treated bar that I threaded to simulate an action, (1.062 tpi), with the big nut on the end to pull against.
The other two pieces are the end from a HV barrel with a 16 tpi that a Remington has, and the end of a barrel with a 18 thread for a Viper, (or Panda). They are tghreaded on the other end to accept a nut as the other back-up when placed in the hollow ram jack.
You can see how I screwed the pieces together and inserted the assy into my 60 ton Hollow Ram Jack.
Both the regular 16 thread and the "16 over 18" withstood a full 30 ton pull with no ill affects. Sometime today, I will put it back in and see just what it takes to bring the thread to "failure".
How do I know it was 30 tons?? All of our Simplex Pumps have precision gages graduated in 100 pound increments,all the way to 10,000 psi. I took the gage to 5000 psi. That hollow ram is 60 tons at 10,000 psi
I had Geramo take these and post then so the Forum could see what I did, and how it worked. I suppose the results speak for themselves........jackie
In the thread "thismay be a silly question" downstream, we got into the discussion of the actual strength of a thread, mainly my idea of establishing a 16 tpi, (threads per inch), over an 18 tpi, so you could use a take off Panda or Viper barrel in a Remington Action. I made up some parts to test the strength of my "16 tpi over a 18 tpi, since there was a question of safety.
The shorter dark piece of bar stock is the 4140 commercial heat treated bar that I threaded to simulate an action, (1.062 tpi), with the big nut on the end to pull against.
The other two pieces are the end from a HV barrel with a 16 tpi that a Remington has, and the end of a barrel with a 18 thread for a Viper, (or Panda). They are tghreaded on the other end to accept a nut as the other back-up when placed in the hollow ram jack.
You can see how I screwed the pieces together and inserted the assy into my 60 ton Hollow Ram Jack.
Both the regular 16 thread and the "16 over 18" withstood a full 30 ton pull with no ill affects. Sometime today, I will put it back in and see just what it takes to bring the thread to "failure".
How do I know it was 30 tons?? All of our Simplex Pumps have precision gages graduated in 100 pound increments,all the way to 10,000 psi. I took the gage to 5000 psi. That hollow ram is 60 tons at 10,000 psi
I had Geramo take these and post then so the Forum could see what I did, and how it worked. I suppose the results speak for themselves........jackie
P
Peter
Guest
whooda thunk?
Dave Short
New member
I could hear the drum roll as I scrolled down through the pictures........Then I got to the end and realized that you didn't take the assembly all the way to the failure (yield) point......I'd hoped to see how the joint failed and at what pressure.
Still, very informative.
-Dave-
Still, very informative.
-Dave-
20 threads per inch would also be interesting..
Since Savage actions are threaded 20tpi it would also be interesting to see at what point they too would fail. If not mistaken both Reminton and Savage engineers have stated their actions were designed to withstand up to 135,000psi before failure. I beleive the Machinist Hand Book rates these threads up to 150,000psi.
Keep it safe Jackie.
Rustystud
Since Savage actions are threaded 20tpi it would also be interesting to see at what point they too would fail. If not mistaken both Reminton and Savage engineers have stated their actions were designed to withstand up to 135,000psi before failure. I beleive the Machinist Hand Book rates these threads up to 150,000psi.
Keep it safe Jackie.
Rustystud
Dave Short
New member
My bet is that, if pushed to failure, it will fracture at the last thread next to the shoulder........I don't think the threads will budge.
-Dave-
-Dave-
jackie schmidt
New member
Rustystud
Threads area strange animal. You would think that a finer thread would not be as strong, but the added area of more threads plays into this.
As soon asI get a chance, I will slip the assy back into the jack and take it up in slight increments untill it fails.
As far as actual tonnage on the thread when a case fires, it is a ridiculous small amount when compared to the strength of even the 16 tpi over the 18tpi.. I sectioned a 308 case at the head, and it measures close to .400 on that inside diameter at the web. Using your pressure formula of bolt thrust, (in psi), divided by 2000, you come up with:
.4 divided by 2 = .200, square this and you get .04, multiply this by 3.14 and you get .1256, (area of inside of case), x 60,000 psi gives you about 7600 psi at the bolt face, divided by 2000, gives you about 3.8 tons.
Now, I doubt the actual barrel sees much more, but suffice to say that a thread that will hold 25+ tons of pressure is in no danger of failing under anything that a case can produce.
I suspect the bolt lugs will fail before the threads would be blown out the front.........jackie
Threads area strange animal. You would think that a finer thread would not be as strong, but the added area of more threads plays into this.
As soon asI get a chance, I will slip the assy back into the jack and take it up in slight increments untill it fails.
As far as actual tonnage on the thread when a case fires, it is a ridiculous small amount when compared to the strength of even the 16 tpi over the 18tpi.. I sectioned a 308 case at the head, and it measures close to .400 on that inside diameter at the web. Using your pressure formula of bolt thrust, (in psi), divided by 2000, you come up with:
.4 divided by 2 = .200, square this and you get .04, multiply this by 3.14 and you get .1256, (area of inside of case), x 60,000 psi gives you about 7600 psi at the bolt face, divided by 2000, gives you about 3.8 tons.
Now, I doubt the actual barrel sees much more, but suffice to say that a thread that will hold 25+ tons of pressure is in no danger of failing under anything that a case can produce.
I suspect the bolt lugs will fail before the threads would be blown out the front.........jackie
jackie schmidt
New member
Just took it to Failure
My men were installing some bronze bushings into some new rudder tubes, so before they put the jack up, I re-installed the test rig ito the hollow ram. I first took it to a flat 5,000 psi to confirm things, and the thread was not compromised, I then took it up just a little at a time, checking the thread each time. At just under 6000 psi on the gage, (about 35 to 38 tons), I heard a distinct "pop". The 16 over 18 thread failed. I removed it, and all of the theads on the "shank" were stripped. I then cleaned out the "action piece", screwed the regular 16 thread into it, and it failed at about 6500.
Geramo is out oftown now, I will get him to take some pictures of the failed threads when he gets back.
Incidentally, the ID threads in the piece of Heat Treated 4140 still look pretty good.
Anyway, this gives the Forum a good idea just how much tonnage a typical 416R barrel thread will take before failure. Even the "16 tpi over the 18 tpi"........jackie
My men were installing some bronze bushings into some new rudder tubes, so before they put the jack up, I re-installed the test rig ito the hollow ram. I first took it to a flat 5,000 psi to confirm things, and the thread was not compromised, I then took it up just a little at a time, checking the thread each time. At just under 6000 psi on the gage, (about 35 to 38 tons), I heard a distinct "pop". The 16 over 18 thread failed. I removed it, and all of the theads on the "shank" were stripped. I then cleaned out the "action piece", screwed the regular 16 thread into it, and it failed at about 6500.
Geramo is out oftown now, I will get him to take some pictures of the failed threads when he gets back.
Incidentally, the ID threads in the piece of Heat Treated 4140 still look pretty good.
Anyway, this gives the Forum a good idea just how much tonnage a typical 416R barrel thread will take before failure. Even the "16 tpi over the 18 tpi"........jackie
Talk to some of the tester..
Jackie:
Isn't Bill Wiseman in Texas. He make test barrels for the shooting industry. I think he also does some testing for the gun industry. It might be interesting to talk to a barrel tester to find out if barrels let go more frequently or actions let go more frequently. I know P.O. Ackley did a lot of experimentation with the P14 and P17 actions. He said you could not blow up one of these actions. I hear he tried real hard. With Wildcats based on the 30-06, 308, and 7X57 cases.
Jackie both the Machinist Hand Book and most steel manufactures can and will give you the physical and mechanical strengths and properties of the steel. The steel manufactures have the formulas (alloys) down to an art.
Good luck and be safe
Rustystud
Jackie:
Isn't Bill Wiseman in Texas. He make test barrels for the shooting industry. I think he also does some testing for the gun industry. It might be interesting to talk to a barrel tester to find out if barrels let go more frequently or actions let go more frequently. I know P.O. Ackley did a lot of experimentation with the P14 and P17 actions. He said you could not blow up one of these actions. I hear he tried real hard. With Wildcats based on the 30-06, 308, and 7X57 cases.
Jackie both the Machinist Hand Book and most steel manufactures can and will give you the physical and mechanical strengths and properties of the steel. The steel manufactures have the formulas (alloys) down to an art.
Good luck and be safe
Rustystud
M
Mark IV
Guest
Jackie:
Thanks very much for the photos and your comments. This Forum is fortunate to have someone with your knowledge to contribute to us.
Thanks very much for the photos and your comments. This Forum is fortunate to have someone with your knowledge to contribute to us.
Butch Lambert
Active member
Nat,
I wouldn't speak to Bill Wiseman if he were the last person on the earth. You and Jackie may, but if you visit with some in the industry that have been around awhile you wouldn't either.
Butch
I wouldn't speak to Bill Wiseman if he were the last person on the earth. You and Jackie may, but if you visit with some in the industry that have been around awhile you wouldn't either.
Butch
F
frwillia
Guest
Fine thread bolts are stronger than coarse threaded bolts because the bolt tensile stess area is bigger due to reduced thread depth. I'm not where I can get my hands on my Machinery's handbook for a couple of days to look at the equations, and I don't remember for sure if it takes more length of threads for finer threads to break a bolt, but it may.
In this case, apparently the thread length was not enough for the tensile stress area of the barrel to be the limiting factor since the threads sheared off.
I'm not surprised they pretty much all sheared if any sheared. Once the first one goes, there are less to take the load, so more go, and then they all go. The barrel didn't pull in two so the threads are in fact the weak link, but they are plenty strong compared to the axial loads put on them.
Fitch
Boyd Allen
Active member
I have the remains of a Savage 110 that was overloaded to the point of failure. The old fellow who it belonged to got lazy about looking into his '06 cast bullet cases and apparently double or triple charged with 4227. The case failed flush with the end of the barrel and the top of the receiver ring came off, splitting on either side along a line that was coincident with where the lug abutments met the ID of the receiver. Incidentally, the gas baffle was never found, having been blown off of the bolt body. He was wearing glasses and had his left hand on the rear sand bag. There was no significant injury. The stock was in splinters, barrel ejected forward onto the ground, apparently undamaged, and the bolt stayed in the action, sort of. At least it did not come back into the shooter's face.
jackie schmidt
New member
Boyd
All bets are off in the advent of a case failure due to a SEVERE overload. Or even a severe pressure condition caused by some other circustance, such as somthing crammed up the barrel. In cases like this, the introduction of high pressure gasses escaping into areas that are not designed to contain them can wreck havoc on all parts.
What is the topic here is the circumstance where a thread could fail under what would be considered normal Rifle performance. By showing that just about any thread has tremendously more holding ability than would ever be encountered in that normal operation is my only point.......jackie
All bets are off in the advent of a case failure due to a SEVERE overload. Or even a severe pressure condition caused by some other circustance, such as somthing crammed up the barrel. In cases like this, the introduction of high pressure gasses escaping into areas that are not designed to contain them can wreck havoc on all parts.
What is the topic here is the circumstance where a thread could fail under what would be considered normal Rifle performance. By showing that just about any thread has tremendously more holding ability than would ever be encountered in that normal operation is my only point.......jackie
D
Dennis Sorensen
Guest
Jackie, if it isn't too much trouble... what if you cut the number of threads in half (.400" of threads instead of .800" of threads) and ran the pressure up... my guess is they would still hold...
Gene Beggs
Active member
Very impressive
Jackie
This is a very impressive test!
This would be a perfect way to determine the strength of my differential thread indexing bushing.
I was considering testing to destruction with an action but I do not have one I would want to destroy. I believe your method would be better, safer, and would not destroy a good action. What do you suggest; how can we do it?
Gene Beggs
Jackie
This is a very impressive test!
This would be a perfect way to determine the strength of my differential thread indexing bushing.
I was considering testing to destruction with an action but I do not have one I would want to destroy. I believe your method would be better, safer, and would not destroy a good action. What do you suggest; how can we do it?
Gene Beggs