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How Many Tune Rifles with Action Screw Torque

 
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  #15  
Old 11-15-2010, 09:32 PM
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Re: How Many Tune Rifles with Action Screw Torque

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Originally Posted by Broz View Post
Interesting topic. I hope to learn something here. I always figured if it was bedded properly it should not matter if it is 50 or 65 in lbs.

Jeff
a 1/4-28 screw is way over tightened (past it yield point) with anything much more than 10 ft. lb. Normally 50 to 60 in. lb. is about the max. Buy a can of Neversieze with Nickel (Donot use Loctite Antisieze!!), and lightly coat the threads with a small paint brush. Then torque the screws down to about 40 In. Lb. for starters. That 40 in. lb. is actually over tightening them, but it's a start. You probably will be able to get by with 30 in. lb. of torque as you can cut the torque value in half when using Neversieze compound. Another thing todo is to replace the screws after retorquing them a few times due to stretch (they will be grade five if they are black, and not as good if they are stainless steel). The best screws are from Premier, Karr, and Allen. Unbrako are right behind these; with the first two being the best you can buy.
gary
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  #16  
Old 11-16-2010, 07:41 AM
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Re: How Many Tune Rifles with Action Screw Torque

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Originally Posted by The Duke007 View Post
I have a problem with accuracy. I found that the action screws were a little loose. I tightened them to 60 ibs. Does anyone know if this would fix the problem? I would go to the range but I dont have time right now but if someone knows it would help.
That's kinda' the point, Duke,, there are no set rules. I think if you can effect accuracy with screw torque you've got bedding problems. I'll , also, point out that there is a difference in torque recommendations between lubricated and non-lubricated threads.
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  #17  
Old 11-16-2010, 09:25 AM
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Re: How Many Tune Rifles with Action Screw Torque

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Originally Posted by elkaholic View Post
Very interesting topic! I have seen rifles that were finicky about torque but I always felt it was a bedding problem. I believe if an action is properly bedded, there is a much larger window of acceptable torque and only enough torque is needed to keep things from moving with additional torque not affecting anything one way or the other. I will be very interested,however; in what others have found.......Rich
+1

I have found that if the pillars and bedding are correctly installed it rarely makes any difference.

I use 55 to 65 inch pounds on all fully bedded and pillared actions (This includes the stocks
with integral bedding blocks).

"But" on factory stocks, be it wood,plastic or synthetic if they have non pillars or bedding
It Does make a difference. Start at 35 inch pounds (Minimum) and work up 5 Inch pounds
at a time and there will be a sweet spot if you have good consistant loads and a reasonable
barrel.

The problem with this process is that the group size and POI can change over time and
condition changes.

It is always best to do a full pillar bed if consistant performance is desired.

Just my experience.

J E CUSTOM
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Last edited by J E Custom; 11-17-2010 at 08:34 AM.
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  #18  
Old 11-16-2010, 12:04 PM
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Re: How Many Tune Rifles with Action Screw Torque

remember the max torque value for a stainless steel screw is less than half of what a stanadar black steel cap screw is. The same can be said for tensil strength and shear strength as well. It's also a very good idea to at least put a drop of oil on the threads before threading them in the holes
gary
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  #19  
Old 11-17-2010, 07:21 AM
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Re: How Many Tune Rifles with Action Screw Torque

Lubing threads, oil or anti-sieze, increases torque applied by 50% of indicated.
Mechanically speaking.

Max torqe on action screws for the USMC M40A3 (Rem 700SA) over glass bedding no pillars was 40inlbs dry. Any thing more would crack the bedding compound. Using McMillan fiberglass stock.

Yes, Beam and Dial Torqe wrenches are more acurate than break-over/clicking style.

Everything flexes, even hard stuff, glass, diamond, etc.
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  #20  
Old 11-17-2010, 11:37 AM
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Re: How Many Tune Rifles with Action Screw Torque

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Originally Posted by BigSkyGP View Post
Lubing threads, oil or anti-sieze, increases torque applied by 50% of indicated.
Mechanically speaking.

Max torqe on action screws for the USMC M40A3 (Rem 700SA) over glass bedding no pillars was 40inlbs dry. Any thing more would crack the bedding compound. Using McMillan fiberglass stock.

Yes, Beam and Dial Torqe wrenches are more acurate than break-over/clicking style.

Everything flexes, even hard stuff, glass, diamond, etc.
I think you missunderstood my comment. When coating threads with Neversieze you can (and should) reduce the actual applied torque to the threads by 50%. I've personally found it to be closer to 30% due to thread quality, and contact values. If the thread was aircraft quality and ground, then yes I'd reduce the torque value by 50%. This and the fact that most all bolts use a rolled thread instead of a cut thread gives me the numbers. Virtually all threads with the exception of a ground thread with a proper helix angle will not hold 100% of their torque value. It's the nature of the beast, and also is why Loctite is in business. You torque a bolt down to 50 ft. lb. and check it a year later and it's maybe 40 ft. lb. Plus bolt quality varies all over the place unless you use a premium quality bolt. In high stress areas many folks are now useing a dial indicator to measure thread stretch rather than applied torque (normally only seen the a nut & bolt). Also 95% of the bolt manufaturers will tell you it's almost a waste of time to torque a bolt to a certain spec without a hardened washer under the head.

The reason the glass bedding is cracking under compression is not due to torque, but the reciever acting as a wedge trying to split the stock. There are compounds that will not split under a hundred pounds of torque, and are readilly accessable to the masses. Yet whoever is putting them together is still stuck in the 1970's. This also kinda shows a flaw in the stock design as well. It's a well known problem with all round actions, and pillar bedding stops this.
gary
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  #21  
Old 11-21-2010, 05:07 AM
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Re: How Many Tune Rifles with Action Screw Torque

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Originally Posted by Trickymissfit View Post
I think you missunderstood my comment. When coating threads with Neversieze you can (and should) reduce the actual applied torque to the threads by 50%. I've personally found it to be closer to 30% due to thread quality, and contact values. If the thread was aircraft quality and ground, then yes I'd reduce the torque value by 50%. This and the fact that most all bolts use a rolled thread instead of a cut thread gives me the numbers. Virtually all threads with the exception of a ground thread with a proper helix angle will not hold 100% of their torque value. It's the nature of the beast, and also is why Loctite is in business. You torque a bolt down to 50 ft. lb. and check it a year later and it's maybe 40 ft. lb. Plus bolt quality varies all over the place unless you use a premium quality bolt. In high stress areas many folks are now useing a dial indicator to measure thread stretch rather than applied torque (normally only seen the a nut & bolt). Also 95% of the bolt manufaturers will tell you it's almost a waste of time to torque a bolt to a certain spec without a hardened washer under the head.

> I was seconding your opinion. Yes, you have also enlightend me as to types of bolt quality and their influence. You have helped me to understand my own theories better. Thanks.

The reason the glass bedding is cracking under compression is not due to torque, but the reciever acting as a wedge trying to split the stock. There are compounds that will not split under a hundred pounds of torque, and are readilly accessable to the masses. Yet whoever is putting them together is still stuck in the 1970's. This also kinda shows a flaw in the stock design as well. It's a well known problem with all round actions, and pillar bedding stops this.
gary
>I thought the cracking compoung had something to do with the round action. Thanks for confirming this, and the tip with pillar bedding. I'm sure this will help others, as well.
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