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Armorers Wrench/Torque question


eward4

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I'm working on my first build so I'm doing everything I can to not screw it up! I have this armorers wrench and just want to know if I can get proper torque for the castle nut with the torque wrench slot at the opposite end from the castle nut wrench end? All wrenches I've seen the torque wrench slot is just behind the wrench itself. Like the wrench I have with it just behind the barrel nut wrench. Appreciate any help! 

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Edited by eward4
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My MagPul wrench is setup similarly -- 1/2" drive socket nearest barrel nut wrench, and opposite the castle nut wrench.

MagPul's website says the torque specs listed on the wrench are correct for the setup. They're identical, IIRC, to the military torque specs.

 

Short answer: Yes, I believe so.

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This is a "crow's foot" setup.  When working with a torque wrench and a crow's foot, you set the torque wrench at 90 degrees to the crow's foot, and torque your setting.

FWIW, that castle nut torque spec is irrelevant.  It's not the barrel nut, which has a wideass spec of 30~80lb/ft.  The castle nut is 40lb/ft, but snug that damn thing up, then STAKE the receiver endplate into the slots in the castle nut.

No matter what the prior popular belief of one super-gunsmith here was, and he stated that such an action was "mangling parts" because he wanted to use loc-tite there - DO NOT use loc-tite there, Snug that thing up good, STAKE those two slots that are available into the castle nut (You'll never get all three, not possible), and you'll never have a problem.

This is the preferred tool for staking that:

Automatic centerpunch. Lowe's, Harbor Freight, whatever.  It's cheap.

image_24936.jpg

Torque wrench on crow's foot - set it up like this, if you need to go through it:

WrenchAdp.jpg

Staked receiver endplate, with the automatic center punch:

440965238_stakedendplate.thumb.jpg.9b2652241ce24e8165b772700e69e620.jpg

Edited by 98Z5V
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Thanks for the reply! I do understand the crows foot setup and having it at a 90 degree angle but what I'm wondering is will the distance from the torque wrench socket to the castle nut wrench end affect the torque? I'm putting a Strike Industries enhanced castle nut and end plate on my gun and there's no where to stake it so I'm just going to torque it to spec but was just wondering about this wrench I have getting it right. No big deal, just wanted some ideas since I'm learning this as I go along. Thanks!

IMG_1813.JPG

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10 minutes ago, eward4 said:

 will the distance from the torque wrench socket to the castle nut wrench end affect the torque?

Yes, but not enough to make a difference on this part.  The torque wrench being further away from the attachment point on the armorer's wrench will increase the torque.  There's a formula for figuring that out:

https://www.finishing.com/118/94_crows_foot_torque.shtml

Show me a picture of a tape measure beside your armorer's wrench, and I'll tell you exactly what it will be, and spell out the formula for that armorer's wrench. :thumbup:

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43 minutes ago, 98Z5V said:

Yes, but not enough to make a difference on this part.  The torque wrench being further away from the attachment point on the armorer's wrench will increase the torque.  There's a formula for figuring that out:

https://www.finishing.com/118/94_crows_foot_torque.shtml

Show me a picture of a tape measure beside your armorer's wrench, and I'll tell you exactly what it will be, and spell out the formula for that armorer's wrench. :thumbup:

Here you go! The wrench is about 12" long and about 7.25" from the center of the castle nut wrench to the center of the torque wrench socket.

IMG_1816.JPG

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43 minutes ago, 98Z5V said:

^^^  This is why I don't complicate shiit with complicated shiit, FWIW... :thumbup:

It's not complicated. That castle nut goes on just like any other castle nut and end plate. I'm just trying to figure out how torque is affected by the torque wrench socket being so far from the castle nut end of the armorers wrench. 

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17 minutes ago, eward4 said:

It's not complicated. That castle nut goes on just like any other castle nut and end plate. I'm just trying to figure out how torque is affected by the torque wrench socket being so far from the castle nut end of the armorers wrench. 

People don't have these issues with standard parts, special castle nuts, and a receiver endplate that is complicated like yours. They just don't. They just tighten it down, stake the damn thing, and never have to worry about anything else, ever in the life of their recoil system, and it never loosens up... So... Yes, you complicated shiit with complicated shiit, and you're worried that it might come loose later one, and you want to make sure it's exactly on spec due to that...

  I hope that makes sense.

So, you're looking at about 7.25" of extension, minus diameter (or thickness). You're about 1" off of that, so use 6.25" for your calculations. Depends on your torque wrench, really, and how far the pivot head is away from the center of the ratchet...  but the real truth is that it won't matter.

That would matter, if it was straight on - torque wrench lined up with your extension, in this case either 7.25" or 6.25", witchever method you believe in.  When you torque it at 90 degrees - it negates that extension, every time. That's why I linked the information that I did. Beyond that first post in what I linked, further below, like 4th reply down, is the information that you really need.

Quote

A. If the crowsfoot is put on at a 90° angle and not at the end increasing the length, it will not effectively change the torque value. The overall length of the lever will be the same for the applied force.

The rest of the answers for calculating the increased length, 7.25, or 6.25, are in the article I linked.  Short answer - set it up on a 90 degree angle, like should be done when working with a crow's foot, and it doesn't really matter. 

I think I said that right away - set it up at a 90 degree angle...  :thumbup:

Good luck.

Edited by 98Z5V
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2 minutes ago, 98Z5V said:

I think I said that right away - set it up at a 90 degree angle...  :thumbup:
 

Yeah, I said that...

1 hour ago, 98Z5V said:

This is a "crow's foot" setup.  When working with a torque wrench and a crow's foot, you set the torque wrench at 90 degrees to the crow's foot, and torque your setting.

 

Set it up how you want, calculate what you want. Do what you want. 

You're over-thinking it.

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32 minutes ago, 98Z5V said:

Yeah, I said that...

Set it up how you want, calculate what you want. Do what you want. 

You're over-thinking it.

You're right; I'm over thinking it! I always do! I'm unfortunately like that with about everything I do.  Like I said, this is my first build so I'm just making sure I'm getting everything right. I appreciate the help! 

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57 minutes ago, eward4 said:

It's not complicated. That castle nut goes on just like any other castle nut and end plate. I'm just trying to figure out how torque is affected by the torque wrench socket being so far from the castle nut end of the armorers wrench. 

Here is the answer to that very question; if the torque wrench is at a 90° angle to the armorer's wrench, there is no effect, you'll get the torque that you set the wrench to get. If you use the torque wrench in line with the armorer's wrench, you'll get 1.75 times your torque wrench setting.

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Okay, I've never been able to wrap my head around the idea of keeping a crowsfoot wrench (or armorer's wrench, in this case) at 90° to the torque wrench handle.

Seems to me, the armorer's wrench is the same length, regardless of the position of the torque wrench.

The torque wrench is designed to apply torque at the 1/2" square drive. If you set it to, say, 40 lb-ft, you get 40 lb-ft at the drive. This torque is transferred to the armorer's wrench, which transfers it to the castle nut.

You're not adding any length to your lever (the torque wrench + armorer's wrench) by varying the position of the armorer's wrench in relation to the torque wrench.

 

I guess I just need to rig something up to test one wrench against another to either prove or disprove my thought process to myself...

Edited by COBrien
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Most socket torque wrenches are accurate when you are using socket attached directly to the wrench square drive.  Using the crowsfoot at 90 degrees to the length will give you a slightly different amounts of torque on the nut  remember that the actual amount of force your arm is applying is figured at the breaking swivel of the wrench the length of the handle only reduces the force your arm applies.  .... and I may be full of bull hockey,too!LOL

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90 degrees eliminates that.  Doesn't matter the length.  You go straight on, and you increased your leverage. You go 90, you increased no leverage, no matter what the length of that 90.   Anything you measure in a difference will be negligible...    :thumbup:

That is why you run a crow's foot at 90.

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