Custom Wrench

[R W]

Attached is a picture with the calculaton for the diminished torque when used with an extension. (Courtesy of Dale M.)

This formula differs from the BELKNAP calculator.
The Divisor A ( first calculation) and Dividend A (second calculation) should replaced by the L (length of wrench) in both cases.

[slow50]

nice job. what did you do to heat treat it after bending and welding it? i ask becuase i fix specialty tools at work sometimes when they break and from what ive learned if you dont treat it some how its just gona break again. so far what works best for me it get it red hot then quinch in heat treat oil. those calculation charts are cool good to know. do you guys not have a torque checker? we have one at work and its amazing how much different extenstions and what not change the torque.

[Don52]

This formula differs from the BELKNAP calculator.
The Divisor A ( first calculation) and Dividend A (second calculation) should replaced by the L (length of wrench) in both cases.

The Belknap calculation is correct.
The one in my previous post is wrong.
Attached is my derivation.
Sorry for the confusion

[mediaad]

Thanks!!!!!!!!!!!!!!!!!!!!!!!!!

[Don52]

what did you do to heat treat it after bending and welding it? i ask becuase i fix specialty tools at work sometimes when they break and from what ive learned if you dont treat it some how its just gona break again. so far what works best for me it get it red hot then quinch in heat treat oil.

In this case the hot bend in the wrench was so far away from the bolt that the stress was very much diminished by the moment arm of the extension so I just let the wrench cool off in the air.

[Don52]

The engineer on the wrench project wanted to use a wrench that had a part number and was readily available from McMaster Carr because we can get it delivered overnight for standard shipping. Unfortunately the Armstrong version of the ratcheting box wrench that McMaster Carr stocked didn’t have a stop on it so the hex would pass right through it. To solve the problem I drilled a 3/32” hole thru the hex using a solid carbide drill because the hex is hardened. I was surprised when I pressed a 3/32” spring pin into the hole because the hardened hex key shaved the OD spring pin as you can see. For the second longer hex I drilled a 1/8” hole and glued in a 3mm dowel using Loctite 680. This resulted in a neater job.

[justweldthis]

Nice welding

Just jim

[Don52]

Attached is a picture of the wrench in operation.