torquing barrel nut

[Fuj']

So who is making/selling those new style barrel nuts? Liking the looks. :cool: And the standard nut wrench fits?

Mikie.....Dave say's no problem, and I'm saying my two wrenches did not fit.
Actually the reason I sent it back was, the threads were loose to the point that
once fully threaded and before tightening, the nut could be rocked back an forth.
This was all large shank. My particular nut should have never made it passed
inspection.

[Nor Cal Mikie]

Thanks Dave and Fuji. Just when we thought all nuts were the same. I have noticed, it depends on who cuts the barrel threads.
Some nuts are a little snug but a little off the points and most nuts will fit. I prefer snug than sloppy. After all, they ARE machined. ;)

[Dave Hoback]

Mine is Small Shank. This is the same with barrels. How many times have we seen people come and say their barrel nut won’t screw on the new barrel threads, but fine on the old barrel? And we’ve told them to use sand paper on the the barrel threads. It’s because the sizes are often called 1-1/16” & 1–1/8” for Small & Large Shank. So, 1.062” & 1.125”. But in actually, they are 1.055” & 1.120”, respectively. However, I’ve never heard of any evidence supporting that a slightly tighter or looser fitting barrel nut, lends itself to accuracy differences. Only the overall tightness. The Article Jim did even corroborates this for even using an Aftermarket machined Barrel Nut. They are nicer, better looking & generally better fitting. But does that translate to better accuracy? No, it does not. The barrel to Receiver threading is what dictates how square the barrel is. The barrel nut serves only to lock the barrel in place. So if a nut is slightly loose or slightly tight… as long as it can be torqued correctly, it’s served it’s purpose. While my Barrel Nut was slightly looser fitting than some others I’ve felt, it wasn’t to the extreme that Fuj’ experienced. And my Wheeler wrench fit the nut just fine. The company just sent me the wrench as a kindness. I tighten them to 75ft.lbs. And it is locked in place.

Oh, the ones I have, once fully threaded they did not rock. They were simply a bit looser threading on. So that, coupled with Fuj’s not fitting the barrel wrenches he had, makes me think he just had a dud. Which they would have gladly taken care of. At least the guy I dealt with, who was one of the owners. Super nice Canadians, eh?

[Herzo]

I just purchased am Axis in 6.5 Creedmoor (the most cost effective rifle in the rack) as a "donor" action. The Brux barrel is still a few weeks out and wishing to check out my scope setup without purchasing ammo in a new caliber, I decided to install a Steven's barrel in .308. Not only was the nut torqued by their trained gorilla, but they decided to further secure it with a sealant that makes red Locktite seem wimpy.
I have never had to use this amount of force to remove a Savage barrel.

[Robinhood]

Mine is Small Shank. This is the same with barrels. How many times have we seen people come and say their barrel nut won’t screw on the new barrel threads, but fine on the old barrel? And we’ve told them to use sand paper on the the barrel threads. It’s because the sizes are often called 1-1/16” & 1–1/8” for Small & Large Shank. So, 1.062” & 1.125”. But in actually, they are 1.055” & 1.120”, respectively. However, I’ve never heard of any evidence supporting that a slightly tighter or looser fitting barrel nut, lends itself to accuracy differences. Only the overall tightness. The Article Jim did even corroborates this for even using an Aftermarket machined Barrel Nut. They are nicer, better looking & generally better fitting. But does that translate to better accuracy? No, it does not. The barrel to Receiver threading is what dictates how square the barrel is. The barrel nut serves only to lock the barrel in place. So if a nut is slightly loose or slightly tight… as long as it can be torqued correctly, it’s served it’s purpose. While my Barrel Nut was slightly looser fitting than some others I’ve felt, it wasn’t to the extreme that Fuj’ experienced. And my Wheeler wrench fit the nut just fine. The company just sent me the wrench as a kindness. I tighten them to 75ft.lbs. And it is locked in place.

Oh, the ones I have, once fully threaded they did not rock. They were simply a bit looser threading on. So that, coupled with Fuj’s not fitting the barrel wrenches he had, makes me think he just had a dud. Which they would have gladly taken care of. At least the guy I dealt with, who was one of the owners. Super nice Canadians, eh?

There is a big difference in the od of the threads being slightly undersized and the pitch diameter being undersized. The 2 are not the same. The pitch diameters on a Savage barrel are based on the nominal(1.0625" and 1.125"). The od is not near as critical.

[Dave Hoback]

Yes, you are correct. Sorry. The math involved before hand.. finding the Pitch Radius using ES, TD &TD2 is extremely important. Forgive my over simplification of simply the thread height. But it’s still numbers in, settings made and threads come out. There’s no mysticism.. no art, right? The machine only knows to do what the user tells it. And of course it’s tolerance holding capability, right? My point was a slightly tighter/loser nut doesn’t add to accuracy potential. (And I’m speaking about bore/thread cutting squareness) But the actual “play”, only matters to the clamping torque, right?

I think Fuj’ had a bad specimen. It happens. I’ve had two of these & they don’t rock when threaded on. But they aren’t as tight as other nuts I’ve felt.

[charlie b]

Play in the nut should not matter that much. The squared faces of receiver and nut along with the concentricity of the threads of the barrel and receiver are the important parts. A corollary can be made to a shouldered barrel. The barrel threads and shoulder must be square to the receiver threads and face. The taper of the threads will 'center' the barrel in the receiver bore when it is torqued down.

The play in the nut will affect the strength of the threaded portion. Not really an issue for our application.

I would assume (bad thing) that most of these nuts are being made on a CNC. If so it could be as simple as someone setting up the machine wrong, or having an improper cutting bit installed. If the mfg relies on manual QC they might not check carefully enough. Easy enough to mess it up. Sometimes a nice phone call or email can fix the issue.

[Robinhood]

The taper of the threads will 'center' the barrel in the receiver bore when it is torqued down. :o

[charlie b]

Do you think something else will center the barrel? There is slop in all threaded connections. The receiver face and nut face will make the barrel stay in line with each other, but, neither will center the barrel.

[Dave Hoback]

I certainly defer to Robin on single point threading. I couldn’t tell you which bits work best, or give pointers. I simply understand the “HOW To” of doing it. Conceptual knowledge, I don’t have working knowledge as I don’t have a lathe.

[Robinhood]

There are forces being applied outside of the thread surfaces being pulled together. Those forces can and do pull barrels off center. When you move that thread off center the barrel now is held back on the side that closes up and that pushes the muzzle in the opposite direction. I have spent the time with test indicators and V-blocks and loose thread fits never have satisfied my tolerences. I could have done something wrong. The plan is to get everything right but sometimes a theory kicks your butt.

[Fuj']

There are forces being applied outside of the thread surfaces being pulled together. Those forces can and do pull barrels off center. When you move that thread off center the barrel now is held back on the side that closes up and that pushes the muzzle in the opposite direction. I have spent the time with test indicators and V-blocks and loose thread fits never have satisfied my tolerences. I could have done something wrong. The plan is to get everything right but sometimes a theory kicks your butt.

Yes Sir !! I've run the mill on just about every aspect, of fitting things up.
Spent more hours on the bench then I should have. I have 7 nuts in a box
that I went thru to always find the one that is the tightest fit for a particular
barrel. I also have 3 PTA actions that I pick to have the tightest barrel thread.
A sloppy action fit, combined with a sloppy nut equals target disasters. Other
then my fire forming barrels, all my PTA barrels are shouldered.

[25-204]

You do realize that the distance from the center of the barrel to the square hole in the wrench for the 1/2" square drive will multiply the torque applied. By how much I don't know. I don't use a torque wrench, just tighten them by feel.

[Dave Hoback]

You do realize that the distance from the center of the barrel to the square hole in the wrench for the 1/2" square drive will multiply the torque applied. By how much I don't know. I don't use a torque wrench, just tighten them by feel.

Not when the the barrel nut wrench is positioned 90 degrees on the Torque wrench. Torquing in this fashion yields precise values. This is known by those familiar with Savage & other Barrel Nut setups. (AR15,AR10)

[Rocketvapor]

Old thread, but comes up often.
Torque with wrench IN LINE has a multiplier.
Arithmetic, not Algebra.
I have an 750 in lb wrench that I calibrated (just me being anal) @ 600 inch pounds (50 ft lbs) with dead weight.
Distance from drive center to center of grip area is 11 inches.
My barrel nut wrench is 1.5" from center of nut to center of 1/2" drive socket.
The multiplier for this set up is total length (11" + 1.5") divided by torque wrench length (11").
When wrench clicks @ 50 ft lbs, the multiplier makes the applied torque 13.6% higher, or 57 ft lbs.
Many want to hold everything with the torque wrench 90 degrees to the barrel nut wrench which is fine.
I just find it easier to hold with the two in line.

[aldan]

I am more confused after reading this than before:p