Armstrong 1/2" Torque Wrench Calibration Specialty Tool

[rpcope1]

Greetings,

This is for those of you who own (or know about) Armstrong (or any of the other rebadged versions) torque wrenches and the calibration of them. I've got a Armstrong 64-086 torque wrench which had never been calibrated (and I bought secondhand). I ended up opting to have my local metrology lab calibrate it, rather than ship it off to Angle Repair.

I got to talking with the guy doing the calibration, and he told me that it was about 10 ft-lbs low in places. He mentioned the adjustment was extra tricky on the torque wrench because as he described it, it has an "allen nut" (that's how he described it to me, maybe this is a cap screw with an allen head?) and some other nut behind it which can't be turned with a normal socket (he said it needed some super thin wall specialty socket). He made it sound like they'd have to source this very special socket from Angle Repair just to adjust the wrench. He also mentioned that most torque wrenches they service (like the older Craftsman I had calibrated at the same time) are less of a PITA; I found this pretty interesting, and am kind of curious now if there are any other brands that are a challenge to calibrate.

I wish he had sent me pictures of adjustment mechanism, but has anyone seen this before, or know anything about a specialty tool needed to calibrate this thing?

 

[Packard V8]

I just found this old thread and yes, the Armstrong calibration procedure requires a special thinwall socket to loosen/tighten the lock nut in the handle. If one has that unobtanium piece, the calibration is easy and Armstrongs are especially accurate. They repeat to a closer standard than most others.

FWIW, I used an old Craftsman thinwall 1/2"dr deep well socket and turned it thin enough on the lathe.

It's pretty moot any more, as the Armstrongs have been out of production for some years now.

jack vines

 

[JulianMorrow]

I just bought a Tekton 1/2" torque wrench; as a DIY weekender, I'm wondering how often would it need to be recalibrated. It may be cheaper to just replace it after a few years.

 

[Packard V8]

I just bought a Tekton 1/2" torque wrench; as a DIY weekender, I'm wondering how often would it need to be recalibrated. It may be cheaper to just replace it after a few years.

For the DIYguy, unless you're using it as a hammer or a pry bar, it will probably never go out of calibration.

Having said that, since HF is selling their little digital whizbang torque adapter for $28.95, you never have to worry; you can know to the tenth of a foot pound.

jack vines

 

[dan18774]

I just found this old thread and yes, the Armstrong calibration procedure requires a special thinwall socket to loosen/tighten the lock nut in the handle. If one has that unobtanium piece, the calibration is easy and Armstrongs are especially accurate. They repeat to a closer standard than most others.

FWIW, I used an old Craftsman thinwall 1/2"dr deep well socket and turned it thin enough on the lathe.

It's pretty moot any more, as the Armstrongs have been out of production for some years now.

jack vines

Hello sir may i ask you if you recall the size of the socket you used on the Armstrong 1/2" torque wrench lock nut in the handle please.

Edit: Should have realized when you just said you used some random 1/2 drive socket you'd probably not remember the size.

 

[KnurledNut]

*Updating an old thread for anyone searching.

This isnt a complete tutorial, just some tips to help the next guy.
First off, kudos to @visionguru for mentioning the socket size in a couple other threads:
https://www.garagejournal.com/forum...q-wrench-for-calibration.422748/#post-7908320
https://www.garagejournal.com/forum/threads/turning-grinding-down-a-socket-options.442750/

I picked up one of these wrenches recently and calibrated it using a known-good torque adaptor.
This requires a super-duper thin-wall 11/16 deep socket, which I custom made using a Snap-on 12-point.
I turned it down with a drill and angle grinder.
It also takes a 7/32 hex key. I used a t-handle.
Remove the end cap in the handle. Just pry it out.
To adjust, lock the handle, loosen the nut (standard thread), and then turn the hex to the left to decrease/to the right to increase torque output.
Tighten the nut (no need to go full gorilla here), unlock the handle and test.
The adjuster is fairly sensitive. Unless its way out of calibration (which could mean bigger issues/internal damage), start with quarter to half turn increments.
A very basic job with the right tools.
If your gonna make your own socket, the O.D. needs to be .875” or less, necked down for 1.2”.
(I wish someone manufactured a set of extreme thin-wall sockets.)