I’m not a big stickler for adhering to torque specs in the most exacting way possible. I may be fooling myself but after a lifetime of working on motorcycles, guns, and all manner of things screwed-together, I feel like I can get where I need to be without carrying a set of torque wrenches in a dual shoulder rig. But when trying to wring the last drop of accuracy from a Remington 700 a while back, and reading from multiple sources the importance of a precise 65 inch-pounds of torque for the action screws, I got the Borka set below.
It’s a clever design, made to cam-over when a certain level or torque is attained. By spacing the sockets at different distances from the pivot / break-over point, different torque values can be had.
My personal torque spec for AR15 carrier key screws is “pretty tight, almost as tight as you can, with a short-leg hex key”. But I had the Borka out for something else yesterday when I needed to put a new carrier key on, so I decided to test myself against the Borka. My method actually was very close to the torque spec of these screws, which depending upon your source, is 48 inch pounds on up to I think 52.
Here’s what the set looks like. I’ve had it for probably 4-5 years now and don’t remember what I paid for it but they are available from Manson Precision Reamers: http://www.mansonreamers.com
…and how it’s used. Put the appropriate tool into the appropriate hex cutout. Here I’ve put it into the one for 50 inch-pounds (note that the "50" is etched on the side toward the work). Normally of course I'd be using two hands but somebody's gotta run the camera. Tighten until the handle “breaks over”. If you put the tool in from the side visible in this pic you get 21 inch pounds, by virtue of the fact that the break-over is occurring in the other direction, which has a lower break-over effort.
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