Nut size - confused

[JHZR2]

I have a couple nuts that I need to torque specifically for an application. I can't find the right size nut though. Advice?

One will be loose with a 22mm socket but won't fit a 21mm. 7/8 fits about the same as 22, and 13/16 does not fit.

The other is loose with 17mm, but 16mm doesn't fit. 11/16 is loose but 5/8 won't fit.

Any ideas? I need to but a crowfoot for final fit application, but don't know what to get... If I had to say, 22 and 17mm fit marginally better but both have a lot of movement on the nut. None are snug.

My attempts were with 12mm sockets and standard wrenches from craftsman, fwiw. I then did the experiment with 6-point SK sockets, and the 22mm was a nearly snug fit, but the 17mm one still had a lot of movement.

Thanks!

 

[R80RS]

Could they be Whitworth?

http://www.sat.dundee.ac.uk/psc/spanner_jaw.html

 

[Joe_Power]

Is this the Saturday morning riddle???

 

[JHZR2]

No its real unfortunately. I think these are forged brass parts.

 

[Darwin1138]

Maybe you need a 1/32nd interval socket set, because a 21/32 is 16.66875 mm and a 27/32 socket will be 21.43125 mm.

These sizes were popular like 50 years ago, how old is your application???

 

[expat]

Depending on the application.
Does it matter?

These are moderate sizes (not too big, not very small)

My guess is you should be able to remove, or tighten to any reasonable torque even with a slightly loose fit.

Shim the wrench if you are worried.

 

[loyd]

What are you working on that you need a crow's foot to torque brass nuts?

 

[Donald]

There are some 1/2 mm size sockets but they are made (for example) a 18mm lug nut with rust between the chrome plating and nut. But you have brass.

 

[Merkava_4]

JHZR2, after reading your description, if it were me, I'd get new nuts.

I'm assuming this is on your BMW, correct?

 

[JHZR2]

These are forged brass flare nuts for an AC lineset.

Torquing the 45 degree flares properly is important.

The nuts on the lineset fit better, but every advisement I've seen is to use the nuts from the OEM.

 

[Merkava_4]

Are they on the original AC lineset made in Germany?

 

[GMBoy]

This sounds like a perfect case to use "universal" sockets on. I have a Craftsman set and they really do work pretty well.

 

[JHZR2]

Can't use a socket, need a crowfoot.

 

[expat]

Am I the only one that thinks you might be over thinking this?

Cut a strip (or two) of metal off a Coke can, use it as a shim on the closest oversize wrench.
Job done!

 

[JHZR2]

Yeah that's a great idea!

Mainly concerned with rounding the fastener, busting a crowfoot due to flex, etc.

 

[yonyon]

I'm not familiar with your application, but you're working with brass nuts. You shouldn't need a tool that fits the nut too snugly. By the time you have to worry about the tool slipping and rounding the nut you've already overtorqued it. You're not planning to overtorque it so this souldn't be an issue.

Where is the need to have such a snugly fitting tool? Are you concerned that using a crow's foot and an extension you'll end up with the tool going cocked on the nut? If that's the issue you're better off with a loose fit anyway. Use your other hand or a tool to act as a fulcrum instead of asking the nut to do that job.

 

[paulo57509]

Instead of using a traditional open-end wrench type crowfoot, have you tried a flare nut style crowfoot? It would give you a couple of more bearing surfaces on the nut.

 

[JHZR2]

Originally Posted By: paulo57509
Instead of using a traditional open-end wrench type crowfoot, have you tried a flare nut style crowfoot? It would give you a couple of more bearing surfaces on the nut.


Yes, absolutely. I wasn't clear, but a flare nut crowfoot is indeed my interest. But the fact that they can have some flex is exactly why I'm a little more concerned with this.