How to properly torque suppressor mounts?

[ericoak]

So all my suppressors have recommended torque settings for their suppressor mounts. I am no tool expert, but the only torque wrenches I have ever seen look like the picture below and are used for sockets. How do you use a torque wrench with an open head that is needed to fit around the suppressor mount? Is this a completely different tool?

 

[clandestine]

You use a bit that looks like a chopped down open end wrench that has a square opening for the torque wrench to click into. I think it's called a crows foot or something. FYI, some are too wide to fit the small flats on some mounts so pick the right ones for your application.

FYI, most suppressor mounts call for a good amount of torque so stupid people don't have things loosen up, but it's excessive and can unnecessarily stress the last 1/2 of the barrel which can effect accuracy, and some rare cases even bullet stability.

I clean the threads well, apply rocksett, and install to 15-20 foot points MAXIMUM. This will hold the mount and impart minimal stress.

 

[j_h_smith]

What he said.

 

[swinokur]

it looks like this but as Chad mentioned some are too thick to use.
.

 

[kalister1]

it looks like this but as Chad mentioned some are too thick to use.
.

That is what grinders are for.

 

[ericoak]

What size open ended wrench fits on ar-15 flash hiders/ mount

 

[cap6888]

I just got the new SDTA flashider, it doesn't need to be timed to a certain position. Should I still use a washer, or is Rocksett and a torque wrench all I need?

 

[dontpanic]

What size open ended wrench fits on ar-15 flash hiders/ mount

The A2 uses a 3/4. My AR combi tool has a spot for flash hiders and a place for a 1/2" breaker bar or torque wrench. So I just use that.

This is the one I have. It came in a kit.

http://www.amazon.com/Wheeler-156-999-Delta-Series-Combo/dp/B00806BAN2

 

[outrider58]

Just realize, all these wrench ends ADD torque to the actual setting because they are off the torque axis so keep it below 20 ft/lbs and as stated before, use Rocksett.

 

[Bootknife]

AAC makes a Three Prong Adaptor for the 51t Mount, it is a little pricey about $34.

 

[BigDaddy]

You use a bit that looks like a chopped down open end wrench that has a square opening for the torque wrench to click into.

If the thickness is the problem you can make one with an appropriate sized wrench welded to a 3/8" socket.
If you do this, know that the torque changes in direct proportion to the new length. Use your torque wrench parallel to the new tool, not at some angle to keep the math simple.

example:
From the center male 3/8 stub on the torque wrench to the center of the handle where you grab the torque wrench is 10"
You weld on the socket wrench and now the distance from the open end wrench to the center of the handle is 14"

Old Length = 10" New Length = 14"
Difference = 140% That means 20 ft-lbs of torque with the old length becomes 24 ft-lbs

This is the homemade tool for BMW Airhead driveshaft bolts. It uses the closed end of the wrench, which you wouldn't want for this application

 

[clandestine]

Just realize, all these wrench ends ADD torque to the actual setting because they are off the torque axis so keep it below 20 ft/lbs and as stated before, use Rocksett.

If the thickness is the problem you can make one with an appropriate sized wrench welded to a 3/8" socket.
If you do this, know that the torque changes in direct proportion to the new length. Use your torque wrench parallel to the new tool, not at some angle to keep the math simple.

example:
From the center male 3/8 stub on the torque wrench to the center of the handle where you grab the torque wrench is 10"
You weld on the socket wrench and now the distance from the open end wrench to the center of the handle is 14"

Old Length = 10" New Length = 14"
Difference = 140% That means 20 ft-lbs of torque with the old length becomes 24 ft-lbs

This is the homemade tool for BMW Airhead driveshaft bolts. It uses the closed end of the wrench, which you wouldn't want for this application

I cover this in my AR Class.

I just got the new SDTA flashider, it doesn't need to be timed to a certain position. Should I still use a washer, or is Rocksett and a torque wrench all I need?

No washer needed, just rocksett and torque. Heat set up rocksett and water releases it.

 

[j_h_smith]

I've often wondered how you can meet the torque spec AND properly index a flash hider at the same time.

 

[clandestine]

I've often wondered how you can meet the torque spec AND properly index a flash hider at the same time.

2 ways:

1) Use a Lathe and machine the crush shoulder on the Muzzle Device so it times up. This can take a long time.

2) Use Brake/Suppressor Mount Shims. They come in packs of varied thickness. There is a chart that you can view online to see a general idea of what thicknesses to stack to get the proper timing. It still takes some trial and error.

 

[outrider58]

These work:

http://www.silencershop.com/accessories/muzzle-brakes/aac-shim-kits.html

 

['04 Cummins]

Just an FYI on crowfoot wrenches used on torque wrenches, using the crowfoot at 90 degrees to the torque wrench doesn't affect the torque value.

See the following link for some formulas. The bottom left is the method I mentioned above.

https://www.motorcraftservice.com/renderers/torquewrench/wrench_formula_main_en.asp

 

[kalister1]

2 ways:

1) Use a Lathe and machine the crush shoulder on the Muzzle Device so it times up. This can take a long time.

2) Use Brake/Suppressor Mount Shims. They come in packs of varied thickness. There is a chart that you can view online to see a general idea of what thicknesses to stack to get the proper timing. It still takes some trial and error.

Years ago I built Radar equipment for Westinghouse. We had "shim packs" that you could peel off one layer at a time to get the dimension you need. I don't know if they were off the shelf or custom made for us?

 

[clandestine]

Years ago I built Radar equipment for Westinghouse. We had "shim packs" that you could peel off one layer at a time to get the dimension you need. I don't know if they were off the shelf or custom made for us?

Peel Washers were quite common for AR15's years ago, but you dont see them often anymore.