ATX chassis screw torque value
- Thread starter CST
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Thanks for the reply .however those 4 screws in the AICS chassis are M4 screws...
AT-X AICS not AT-X, not sure where to find a schematic with those torque values.
Maybe try AINA?
Maybe try AINA?
This isn't the answer you're looking for but in the absence of specific values I'll find references for the min. max. torque values for similar fasteners and trend to the lower value with threadlocker to be on the safe side.
Monster Bolts lists the setting torque for a M4 fastener at 4.83 Nm / 43 in/lbs, Holo-Krome lists 5.85 Nm / 52 in/lbs, and another reference listed the min. max. torque for a M4 socket head cap screw at 44 - 51 in/lbs so that fits too.
If it was me, I'd be comfortable torquing them 40 in/lbs with threadlocker and calling it good.
ETA: I missed that you said stainless steel fasteners. If that's the case, disregard the above, those values are referencing black oxide socket head cap screws. For stainless I'd drop that to 25 in/lbs maximum w/ blue loctite.
Edited again: I was mistaken on the fastener size for the AX AICS forend retaining screws, I misread the hex key size as the fastener diameter so on the post-2014 AX AICS the 44 in/lbs is referencing the M6 retaining screws. That being said, a pre-2014 AX AICS lists the torque for the ten blued M4 forend retaining screws as 2 Nm or about 18 in/lbs with blue loctite so they're trending towards the lower end of the spectrum. I tightened some down to 43 in/lbs with blue loctite and there were no shenanigans so I still feel the 40 in/lbs is safe for non-stainless M4 fasteners.
Monster Bolts lists the setting torque for a M4 fastener at 4.83 Nm / 43 in/lbs, Holo-Krome lists 5.85 Nm / 52 in/lbs, and another reference listed the min. max. torque for a M4 socket head cap screw at 44 - 51 in/lbs so that fits too.
If it was me, I'd be comfortable torquing them 40 in/lbs with threadlocker and calling it good.
ETA: I missed that you said stainless steel fasteners. If that's the case, disregard the above, those values are referencing black oxide socket head cap screws. For stainless I'd drop that to 25 in/lbs maximum w/ blue loctite.
Edited again: I was mistaken on the fastener size for the AX AICS forend retaining screws, I misread the hex key size as the fastener diameter so on the post-2014 AX AICS the 44 in/lbs is referencing the M6 retaining screws. That being said, a pre-2014 AX AICS lists the torque for the ten blued M4 forend retaining screws as 2 Nm or about 18 in/lbs with blue loctite so they're trending towards the lower end of the spectrum. I tightened some down to 43 in/lbs with blue loctite and there were no shenanigans so I still feel the 40 in/lbs is safe for non-stainless M4 fasteners.
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Thanks for the insight. The funny thing is the stock comes with stainless and when I removed em there is start of some damage to the hex. (After heatng it to loosen the loctite). That's why I'm asking about torque. The stainless cap screws are way too soft. If I had to fight the loctite anymore I'm very sure I would strip it. Plus the quality of the screws they used is some Chinese crap from Amazon. Only one Allen would fit out of all my different tools. (Too loose)
I don't understand why they didn't use steel alloy unless corrosion is a concern but they use steel alloy for the action screws underneath....
I bought a new set of steel alloys as a back up and ordered some higher quality stainless..
25"lbs doesn't seem like a lot bolting the upper with the heavy action and barrel to the lower. Like the same torque as a scope ring.
So look at this way...for years the typical 6-48 and 8-40 screws that hold bases and scopes to the rifle have been doing so through recoil shot after shot without too much trouble. Friction is awesome, until it's not, depends on the application really and I'm not an engineer but the clamping force on a SS M4 bolt at 25 in/lbs is probably at least several hundred pounds. Between that and the friction between the two mating surfaces, I doubt the chassis will come apart on you.
Swap the SS fasteners for black oxide and you can up the torque values for more clamping force.
Swap the SS fasteners for black oxide and you can up the torque values for more clamping force.
