Action screw torque
- Thread starter double g
- Start date
If bedded properly, shouldn't move once it bottoms out at 5lbs or 50lbs.
If not bedded, probably have to play with it to see what shoots best
If not bedded, probably have to play with it to see what shoots best
65 inch-pounds.
If tightening the action screws is causing 'stuff' to bend, forcing the barreled action and its foundation to conform to one another’s differing forms, then that foundation needs fixin’ done proper.
Look see here: http://erniethegunsmith.com/catalog/i130.html
Look see here: http://erniethegunsmith.com/catalog/i130.html
1/4 28" screws to 40 inch pounds max.
Yes... 65 inch pounds.
Liven The Dream
Gold $$ Contributor
65 t0 70 in. pounds on my Barnard's and 700 in Aluminum Stock.
carlsbad
Lions don't lose sleep over the opinions of sheep.
Lots of right answers to this question. Bolted fasteners are one of my specialties in my day job so I'll discuss this a bit.
Torque is important on an engineered threaded fastener if you are trying to stretch the fastener to some percentage of yield strength for maximum clamping force--think bolted pipe flange in a power plant. Generally bolt torque is calculated based on material and cross sectional area at the root of the thread to preload the bolts to 30 to 70% of yield strength. Stretching the bolt also secures it so that it will not vibrate loose. But we don't have a problem with action screws vibrating loose.
For an action screw, it is not a high strength joint. In fact, too much stress will bend the action causing negative effects.
A good bedding job, along with pillars, will mostly mitigate the effects of too much torque.
An unbedded, unpillared stock will compress the stock material.
The threads in the action are long enough for full strength but don't have much margin as far as depth of threads, especially is the action screw is short by a thread or 2. Both CrMo and SS actions are made of high strength steel, capable of full strength joints. The action screws are also high strength steel.
So looking up the recommended high strength joint torque for a 1/4-28 bolt I find 10 ft lbs (120 in lbs) for grade 5 bolts and and 14 (168 in lbs) for grade 8. This is for a high strength joint (such as a flange). But we don't want to be putting those type of stresses on our actions. But 1/3 of these numbers sounds good to me. That gives us lots of margin to prevent damaging our threads or our actions while providing adequate tension to hold everything together. The strength of the bolt material isn't really challenged. These numbers are verified experimentally by thousands of users over many decades.
So I like the answers above between 50 and 75 in lbs but wouldn't really say any of the others are wrong. If nothing is moving around, then I would not expect problems with using less torque. If you've been using a number successfully, I'd say stick with it.
--Jerry
Torque is important on an engineered threaded fastener if you are trying to stretch the fastener to some percentage of yield strength for maximum clamping force--think bolted pipe flange in a power plant. Generally bolt torque is calculated based on material and cross sectional area at the root of the thread to preload the bolts to 30 to 70% of yield strength. Stretching the bolt also secures it so that it will not vibrate loose. But we don't have a problem with action screws vibrating loose.
For an action screw, it is not a high strength joint. In fact, too much stress will bend the action causing negative effects.
A good bedding job, along with pillars, will mostly mitigate the effects of too much torque.
An unbedded, unpillared stock will compress the stock material.
The threads in the action are long enough for full strength but don't have much margin as far as depth of threads, especially is the action screw is short by a thread or 2. Both CrMo and SS actions are made of high strength steel, capable of full strength joints. The action screws are also high strength steel.
So looking up the recommended high strength joint torque for a 1/4-28 bolt I find 10 ft lbs (120 in lbs) for grade 5 bolts and and 14 (168 in lbs) for grade 8. This is for a high strength joint (such as a flange). But we don't want to be putting those type of stresses on our actions. But 1/3 of these numbers sounds good to me. That gives us lots of margin to prevent damaging our threads or our actions while providing adequate tension to hold everything together. The strength of the bolt material isn't really challenged. These numbers are verified experimentally by thousands of users over many decades.
So I like the answers above between 50 and 75 in lbs but wouldn't really say any of the others are wrong. If nothing is moving around, then I would not expect problems with using less torque. If you've been using a number successfully, I'd say stick with it.
--Jerry
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