I know this is common sense but my OCD needs confirmation. I took the stock off my Browning 725 to look at the trigger group and was curious as to how tight the stock should be. I didn't have the allen wrench that came with it so I used a socket with an allen key attached and a 3/8 ratchet. I tightened the rod until it was just snug and then gave it about maybe 1/10 of a turn. I only had two fingers and my thumb on the head of the ratchet so I wouldn't get too much torque. I would have used a torque wrench if I had something to go by. Anyway, any input would be appreciated.
mliebs
Wood swells and contracts from heat, cold, and humidity. Just "snug it up well" and don't go overboard. Stocks can split from over tightening.
If it wasn't loose when you got it, leave it be. The factory worker who assembled it should have known and been instructed as to what he or she was doing.
If it wasn't loose when you got it, leave it be. The factory worker who assembled it should have known and been instructed as to what he or she was doing.
What you did sounds right to me. If it works loose, just tighten a little more. I doubt you will have to do anything more.
It sounds to me like you used pretty good judgement tightening
your stock. I am with BobK above on this, there does not seem
to be a really precision answer because the wood tends to
change size a lot with humidity changes. I have experienced
some really difficult stocks to remove at times and I always
wondered if they were put on too tight, or just tightened up
from wood expanding.
your stock. I am with BobK above on this, there does not seem
to be a really precision answer because the wood tends to
change size a lot with humidity changes. I have experienced
some really difficult stocks to remove at times and I always
wondered if they were put on too tight, or just tightened up
from wood expanding.
You had your two fingers and thumb on the "head" of the ratchet??? It doesn't sound like you could apply much torque at all that way. I agree that you don't want to apply too much torque, but, OTOH, you don't want the stock to be loose either. If it's loose and you continue to shoot the gun with a loose stock, you can crack/split that stock that way too.
I've never used a torque wrench to measure the torque I use on tightening a stock, but my SWAG is about 5 to 7 ft-lbs is about right. YMMV.
I've never used a torque wrench to measure the torque I use on tightening a stock, but my SWAG is about 5 to 7 ft-lbs is about right. YMMV.
What does bolt size have to do with the amount of torque applied? The calculation for torque has no place to plug bolt size into the formula. Torque is force x distance.mliebs said:
You said you would have used a torque wrench if you had something to go by. Well, how about re-doing it with your torque wrench and tell us how much torque to had to apply to get the bolt moving again or to break it free. If you get up to 7 ft-lbs or so, I think you'll be good, although some may take 10 or 12 ft-lbs of torque.
While this is technically correct, it does not tell the whole story. The allowable torque on any given fastener is determined by several factors, including material grade, bolt size, thread design and clamp load. That said, your recommendation for 7 to 10 ft-lbs of torque is probably correct given the application and bolt sizes in common usage. The critical component here is clamp load as it applies to crushing or splitting the wood.Ulysses said:
Frank
The bolt diameter is 8mm if I recall correctly. The correct torque for a machine bolt is 185-200 inch lbs. This will not hold true for steel vs wood. I generally go on the lite side and use 185 inch lbs.
185 inch-lbs is equal to 15.4 ft-lbs which is more than double the 5 to 7 ft-lbs I suggested. So I wouldn't call 185 inch-lbs as being on the "lite side". It might be safe for some stocks, but I'd prefer to start with the 5 to 7 ft-lbs and see if that is enough to keep the stock snug against the receiver. If not, you can always add a little more tightening force.cfoster said:
Different grades of bolts are rated for varying torques, depending on the application.
With a stock bolt, the limiting factor is the wood. While in typical applications, for an 8mm bolt, the torque values can range form 8 to 29 LB FT (maximum) depending on the grade of the bolt and other requirements.
I would recommend starting with a low value, 5~7 LB FT and using something like Vibra-Tite VC-3 on the threads, if it loosens up go to 7~9 LB FT...
With a stock bolt, the limiting factor is the wood. While in typical applications, for an 8mm bolt, the torque values can range form 8 to 29 LB FT (maximum) depending on the grade of the bolt and other requirements.
I would recommend starting with a low value, 5~7 LB FT and using something like Vibra-Tite VC-3 on the threads, if it loosens up go to 7~9 LB FT...
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