Gunsmithing AICS Torque Sequence

[ShtrRdy]

I'll be receiving my barreled action back from the gunsmith soon, (I hope), and will be installing it in an AICS stock. Is there a preferred sequence to tighten the action screws? For example, is it better to alternately tighten the front screw and tang screw, increasing the torque a little each time? Or to tighten the front screw first and then the tang screw, in a two step process?

 

[smschulz]

Re: AICS Torque Sequence

It's always better to incrementally increase torque on just about anything with multiple screws.

 

[TxShooter63]

Re: AICS Torque Sequence

I do them together. Start each at 20 inch lbs and work up to 50 in 10 in/lb increments. I don't torque the entire 10 in/lbs at once for each move up. I turn each bolt 1/8th of a turn until I reach each level and then move the wrench up 10 in/lbs. I finish off with a 5 in/lb move from 50 to 55. Some people go to 65 in/lbs but on the AICS V-Block chassis I find that 55 is plenty.
I have a .260 and a .300WM in AICS chassis and use the same torque setting for
both.

 

[wtopace]

Re: AICS Torque Sequence

Normally I just snug them both up then click them with the torque driver (this is also on my AICS). Rifle seems to still shoot straight every time.

 

[HarryBallz2029]

Re: AICS Torque Sequence

I normally tighten both down to 35-40 then the front to 65 and the back to 50 to 57(borka tool).

 

[300sniper]

Re: AICS Torque Sequence

start screws. stand rifle muzzle up on it's butt pad. snug front screw. snug rear screw. torque front screw. torque rear screw.

 

[Jackalope33B]

Re: AICS Torque Sequence

According to AINA, torque specs on the ALL AICS Chassis is 53 inch/lbs

 

[E. Bryant]

Re: AICS Torque Sequence

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TxShooter63</div><div class="ubbcode-body">I do them together. Start each at 20 inch lbs and work up to 50 in 10 in/lb increments. I don't torque the entire 10 in/lbs at once for each move up. I turn each bolt 1/8th of a turn until I reach each level and then move the wrench up 10 in/lbs. I finish off with a 5 in/lb move from 50 to 55. Some people go to 65 in/lbs but on the AICS V-Block chassis I find that 55 is plenty.</div></div>

I fear that you are not only overthinking this simple task, but possibly being a bit counterproductive. Here's why - the biggest variable in establishing the proper stress in a fastener is friction. By making such small increments in the applied torque, you may not overcoming the static friction between the fastener and its interfaces, and thus the applied torque fails to add any preload.

For a fastener of this size, there is little need for more than two steps total. Snug the fasteners "finger tight" (approximately 10-15 in-lb), bang the buttstock on the floor a couple of times to settle the action towards the rear, and then torque to the final value.

 

[TxShooter63]

Re: AICS Torque Sequence

My torque sequence comes from having owned a race engine business for 10 years where I torqued thousands of bolts of all sizes. The last increment of 5 in/lbs is really just to make sure both bolts are torqued equally more than to add any additional force. The truth is you could torque these from 35-65 in/lbs and probaby get satisfactory results. Since 53 is the recommended I use 55. The key is to make sure that both bolts are torqued equally and incrementally, so as not to induce any distortion in the action which can be done with a V-block chassis. I am currently doing R&D work with a new company that is designing a chassis similar to the AI's but with a ball milled receiver groove to eliminate the possibility of receiver distortion. Most new chassis designs are going this route for that reason. V-Blocking is just cheaper and easier to hold tolerance on and obviously works pretty well in most cases.

 

[Rthur]

Re: AICS Torque Sequence

I use the sequence 300 has and 53 inch/lbs has always worked for me. In fact the zero seems to be on or within a tenth.

 

[E. Bryant]

Re: AICS Torque Sequence

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TxShooter63</div><div class="ubbcode-body">My torque sequence comes from having owned a race engine business for 10 years where I torqued thousands of bolts of all sizes. The last increment of 5 in/lbs is really just to make sure both bolts are torqued equally more than to add any additional force.</div></div>

While I respect that experience, and having myself torqued a lot of fasteners in engines, I have to point out that there is some difference between a finely-machined ARP stud/nut/washer combination that is coated in moly lube and being "bumped" in 5 ft-lb increments, and a (relatively) poorly-formed off-the-shelf fastener that is dry and being "bumped" in 5 in-lb increments. In the latter case, the static friction is likely substantial enough to prevent any fastener motion with small increments in torque. And if the fastener head does not rotate, then the additional torque didn't have <span style="font-style: italic">any</span> effect on fastener preload. This is why torque-to-yield fasteners and their torque-to-angle tightening process have become so common.

For action bolts, there is no need to get fancy. Snug 'em, bump the stock to settle the action, then tighten them to spec. If there is any concern beyond that, then simply fire the rifle a few times and re-check the torque.

- Eric

 

[kortik]

Re: AICS Torque Sequence

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Eric Bryant</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TxShooter63</div><div class="ubbcode-body">My torque sequence comes from having owned a race engine business for 10 years where I torqued thousands of bolts of all sizes. The last increment of 5 in/lbs is really just to make sure both bolts are torqued equally more than to add any additional force.</div></div>

While I respect that experience, and having myself torqued a lot of fasteners in engines, I have to point out that there is some difference between a finely-machined ARP stud/nut/washer combination that is coated in moly lube and being "bumped" in 5 ft-lb increments, and a (relatively) poorly-formed off-the-shelf fastener that is dry and being "bumped" in 5 in-lb increments. In the latter case, the static friction is likely substantial enough to prevent any fastener motion with small increments in torque. And if the fastener head does not rotate, then the additional torque didn't have <span style="font-style: italic">any</span> effect on fastener preload. This is why torque-to-yield fasteners and their torque-to-angle tightening process have become so common.

For action bolts, there is no need to get fancy. Snug 'em, bump the stock to settle the action, then tighten them to spec. If there is any concern beyond that, then simply fire the rifle a few times and re-check the torque.

- Eric </div></div>

I agree with Eric. Friction related to fasteners is a tricky thing. Don't even need to mention completely unpredictable flat heads.. As far as I can tell based on my own experince, toqueing in for just 2 action screws should be real simple procedure, similar to what Eric suggested, although sometimes it is kind of beneficial to know which one to torque first.