Barrel Torque Ludicrocity

[Kiba]

The print we have says 0.825 +/-1, where is the 822 number published? The 825 number has been standard since 2018 timeframe with the Nucleus launch and several shops, myself included, argued with Ted to make the 825 number standard and keep it for the Coups. We've never run into an issue with the Coup on headspace using 825.

Or does someone else have an old print or an incorrect reference entirely? Instead, using 825 all the numbers match up there.

I did see some early Nukes that were 822/823 range and that caused some very early, very rare issues being that we were cutting the barrels at the time to 823+/- 5 tenths since the number ARC gave me was 825 +/-1, however I haven't seen anything like that since 2018 Gen 1 Nukes.

Document control is always fun!

Don't even get me started on document control and revision control... Was just dealing with that last week actually, the customer emailed one of the program team that was on vacation a redline that didn't make it to document control, and now I have 5 parts in inspection that weren't made to the current rev that need rework, lol

Always fun when you have drawings that are into the double digits of revisions (better yet, double letter revisions which means at least 26 drawing revisions) and you need to keep manufacturing, inspection, vendors, and the customer all working to the current rev... Especially if while you're making parts to the current rev you also need to make spares for decades old aircraft that may require you dig out an old rev and make a specific down rev version of the part for that specific aircraft. So many opportunities to screw up!

 

[bohem]

Document control is always fun!

Don't even get me started on document control and revision control... Was just dealing with that last week actually, the customer emailed one of the program team that was on vacation a redline that didn't make it to document control, and now I have 5 parts in inspection that weren't made to the current rev that need rework, lol

Always fun when you have drawings that are into the double digits of revisions (better yet, double letter revisions which means at least 26 drawing revisions) and you need to keep manufacturing, inspection, vendors, and the customer all working to the current rev... Especially if while you're making parts to the current rev you also need to make spares for decades old aircraft that may require you dig out an old rev and make a specific down rev version of the part for that specific aircraft. So many opportunities to screw up!

Yeah, no shit. That part sucks

 

[wind gypsy]

The print we have says 0.825 +/-1, where is the 822 number published? The 825 number has been standard since 2018 timeframe with the Nucleus launch and several shops, myself included, argued with Ted to make the 825 number standard and keep it for the Coups. We've never run into an issue with the Coup on headspace using 825.

Or does someone else have an old print or an incorrect reference entirely? Instead, using 825 all the numbers match up there.

I did see some early Nukes that were 822/823 range and that caused some very early, very rare issues being that we were cutting the barrels at the time to 823+/- 5 tenths since the number ARC gave me was 825 +/-1, however I haven't seen anything like that since 2018 Gen 1 Nukes.

I googled "ARC tennon Specs" and the first relative link that popped up showed the below image. If you go to their website, Support page links to the same CDG pdf with 0.822. One link below is their other actions which says "not for CDG" and indicates a 0.825".

 

[Aaron Davidson]

Under the locking mechanism of an AWMC ir similar, this way:
View attachment 8787022

I believe that the thread operates the same as a std rem style. Only one side of the thread is in contact and the opposing force is carried on the barrel shoulder. This diagram would be incorrect.

 

[Aaron Davidson]

The ramp thread from Harolds book is money. Absolutely solves the problem, EXCEPT that you will yield the action face, recoil lug or barrel shoulder. Back to square one.

Accept that it will not be tight enough to stay together (magnum diameter case @65k plus) and the right way is to make the thread and shoulder interface as perfect as we can so it can return to the same place. Advantage integral lug, advantage integral base (or no penetrating scope mounting screw), advantage high speed CNC threading, advantage perfectly orthogonal face/thread.

Lighter psi and smaller diameter case do not exp the separation issue.

FYI AR style joints are different, require a different discussion.

Takeaway is: not too tight is the right answer. Too tight should at least be determined by calculation, and stay a safety factor below. 75-100 is just right as a general spec. The friction coefficient is a HUGE player in this problem/solution also.

Barrel joint movement due to everything but recoil is the boogey man that destroys my peaceful nights!

 

[TicTacTex]

I don’t claim to know anything about nothing, but what role does the recoil lug play when torquing an action on to a barrel?

•What material is the lug made from?
•What is the quality of a given material?
•Overall machining quality and consistency?
•Is the material heat treated?

…Just to rattle off a couple of questions that come to mind.

I spoke on the phone with a well known Jedi Master that has used recoil lugs that were apparently made from the same material and process as a Spuhr clamp bar, which raised the question about barrel torque.

 

[flogxal]

SAE

Bespoke IPHY, one of a kind.

 

[MikeMiller]

I talked with Mike R today and asked about the amount of force he uses in his rifles because I had one of his rifles and it never shifted poi cold or hot action, unlike many other bolt actions have

He explained he uses way more torque than most and has his barrel lugs made of special steel that is 45 Rockwell hardened so it does not smash from the torque to accomplish the task. Well he went into far greater detail than that but it was over my head. All I can say is what Tac Ops does works

So I don’t know the minimum torque required but I know it’s a lot more than some here are using

 

[AccuSol-ERN]

I googled "ARC tennon Specs" and the first relative link that popped up showed the below image. If you go to their website, Support page links to the same CDG pdf with 0.822. One link below is their other actions which says "not for CDG" and indicates a 0.825".
View attachment 8788934

View attachment 8788935

This is the EXACT print......and the one linked to their website.

I understand things change, so I always check the manufacturer's website to make sure I get the updated specs.

Don't get me wrong, I am not shitting on ARC.......I just made a decision to no longer offer prefits based on their own print/action inconsistency.

It sounds like .825 +/-.001" is pretty consistent from Bohem and others. However if I am cutting to a print.......then I am cutting to a print......and the burden of error/design is not mine. This is basic machining 101.

I also believe in providing the best customer service and experience possible. Given all this information, the best solution for me moving forward is to have any ARC action in hand when fitting a barrel.

Ern

 

[AccuSol-ERN]

Keep the science coming though.

I do 70lbs, with the occasional increase to get a flute to time, nothing big probably an additional 20--30lbs

Ern

 

[TicTacTex]

I talked with Mike R today and asked about the amount of force he uses in his rifles because I had one of his rifles and it never shifted poi cold or hot action, unlike many other bolt actions have

He explained he uses way more torque than most and has his barrel lugs made of special steel that is 45 Rockwell hardened so it does not smash from the torque to accomplish the task. Well he went into far greater detail than that but it was over my head. All I can say is what Tac Ops does works

So I don’t know the minimum torque required but I know it’s a lot more than some here are using

Talking to Mike is dangerous… Surprised he didn’t sweet talk you into buying another TacOps before y’all hung up. lol

 

[Rubicon Precision]

I believe that the thread operates the same as a std rem style. Only one side of the thread is in contact and the opposing force is carried on the barrel shoulder. This diagram would be incorrect.

Only one side of the thread is in contact, EXCEPT under the “locking tab”, or wtfe you want to call it. When the pinch screw is tightened, the tab is pushed until the lead and flank of the tenon thread are are making contact with the lead and flank of threaded locking tab.

I’ll admit, since the tab is already in contact with the flanks while hand tight, the locking tab being forced slightly further down the flank (maybe .002-.003”?) will very slightly increase tension on the tenon, but it will be minimal spring tension from the tab flexing, before it almost immediately also contacts the lead side of the threads, creating a clamping force (loading both the lead and flank)

The redlined loading in diagram is correct under the locking tab of the AXMC.

 

[chevy_man]

I torque them to 100+. After 110-130 the nut stops moving and the torque just starts ramping so I figure it's done.
I use a bending bar style torque wrenches so I can see the torque, no clickers for me.

Copper based high heat anti-seize because that's what's been on my bench for years.

The M14 (9/16"ish) studs on my truck call for 160 ft lbs. Pretty sure a 1"+ thread isn't going to get hurt by 100-200 ft lbs. (Obviously if you're not using steel this all goes out the window).