Gunsmithing Torque question

[BasraBoy]

Sorry if this is a really dumb question.....

I have a 1/2" square drive torque wrench.

I need a tool for a specific job that i can only find with a 3/8" attachment.

If I buy a 1/2" to 3/8" adaptor to put between the trench and the attachment, does this affect the torque settings on the wrench?

I'm guessing that a different size drive head means a different "gearing" to the 1/2" drive the wrench was calibrated for?

Any help gratefully received...especially if it gives the necessary formula for calculating how to set the wrench!

 

[rijndael]

Re: Torque question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BasraBoy</div><div class="ubbcode-body">If I buy a 1/2" to 3/8" adaptor to put between the trench and the attachment, does this affect the torque settings on the wrench?</div></div>

As long as it's a simple 1/2 to 3/8 reducer, it doesn't matter.

 

[birddog762]

Re: Torque question

it does matter if it is high torque.the reduced portion is not as strong as the thicker and thats where it will break.ymmv

 

[BasraBoy]

Re: Torque question

rijndale / birddog - thanks guys.

The max torque that I need to apply will be under 50ft/lb.

 

[Johnsusername]

Re: Torque question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BasraBoy</div><div class="ubbcode-body">Sorry if this is a really dumb question.....

I have a 1/2" square drive torque wrench.

I need a tool for a specific job that i can only find with a 3/8" attachment.

If I buy a 1/2" to 3/8" adaptor to put between the trench and the attachment, does this affect the torque settings on the wrench?

I'm guessing that a different size drive head means a different "gearing" to the 1/2" drive the wrench was calibrated for?

Any help gratefully received...especially if it gives the necessary formula for calculating how to set the wrench!

</div></div>

As long as the 1/2" to 3/8" adaptor is stamped "Craftsman, Made in USA" it won't be a problem.

John

 

[BasraBoy]

Re: Torque question

Thanks John! In a world where most tools seem to be made in China....that's not bad advice!

 

[rlepage]

Re: Torque question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BasraBoy</div><div class="ubbcode-body">rijndale / birddog - thanks guys.

The max torque that I need to apply will be under 50ft/lb.

</div></div>

50ft/lb is pretty low for a 1/2" drive wrench. I'd use a 3/8" drive torque wrench so it would be in the middle of it's range.

reducer won't affect torque reading as it's based off the center of the drive.

 

[BasraBoy]

Re: Torque question

The wrench I have is calibrated and certified from 10-50 ft/lb on a 1/2" drive. Most of what I need it for is 20-40 ft/lb

How does the size of the drive affect the torque?

I always thought the only benefit of a larger drive was for strength.

Am I missing something?

The reason I asked about 3/8" is because I need a specific attachmentfor a job and can only find it with a 3/8" drive....if I could find it with 1/2" I'd be more than happyy to miss out the adaptor...K.I.S.S

 

[birddog762]

Re: Torque question

in that range you will be fine.some times the only socket dimesionally that will fit into an opening is 3/8,1/4 etc but the " weak link in the chain" is that smaller sq drive or even the socket itself. for the record brand doesnt matter( i have broken them all snap-on,mac,matco,proto at one time or another) just shareing the wisdom gained over a lifetime of touching the wrenches.

 

[dmschmidt]

Re: Torque question

No it will not, you are not putting in a gearing adapter, so it is still a direct connection and thus the torque settings will be correct.

 

[CDiPrecision]

Re: Torque question

Are you putting on an AR-15 barrel?. OR doing a barrel?. Make sure you don't want Inch pounds..

 

[BasraBoy]

Re: Torque question

According to the manufacturer's instructions it is ft/lb.

Barrel nut at ~40 ft/lb, muzzle device at between 20-30 ft/lb

 

[rlepage]

Re: Torque question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BasraBoy</div><div class="ubbcode-body">The wrench I have is calibrated and certified from 10-50 ft/lb on a 1/2" drive. Most of what I need it for is 20-40 ft/lb

How does the size of the drive affect the torque?

I always thought the only benefit of a larger drive was for strength.

Am I missing something?

The reason I asked about 3/8" is because I need a specific attachmentfor a job and can only find it with a 3/8" drive....if I could find it with 1/2" I'd be more than happyy to miss out the adaptor...K.I.S.S </div></div>

Size of drive doesn't affect the torque. Most 1/2" torque wrenches I've seen have a range from ~25 to ~175 ft/lb. The 3/8 from ~5 to 80 ft/lb. I like to try and keep the torque near the middle of the range of the wrench.

Also the 3/8 wrench is usually shorter so you get a better "feel" with it.