Torque developed with a hammer wrench 1

[Ralph2]

Can any "old-timers" recall the rule of thumb to use when "torquing" a nut using a hammer wrench. Seems it was so many hits after it stopped turning with a 10 pound sledge swung by a "good" man.

Thanks
Ralph

 

[JStephen]

If the torque's not important, then it doesn't matter. If it is important, find a better way to measure it!

Seriously, it sounds like that kind of thing would be very dependent on the exact nut, bolt, application, lubrication, and equipment that was being used.

 

[Ralph2]

Very crude by todays standards of course. But bolted joints were made tight to a reasonable consistency long before Snap-On and torque wrenches.
There are still lots of applications where the only wrench that will do the job is a hammer wrench.. Sometimes one would like to differentiate between 3,000 foot pounds and 10,000 at which point the threads are stripped / stretched.
The question though was started by... how much torque can one typically develop with a hammer wrench. The answer I know is... depends on how long one beats on it and how big the boy is that is swinging the hammer. However I vaguely recall a rough rule of thumb... but all the other old timers at work, like myself.... have forgotten the details.

 

[rnd2]

Advice from a good old friend of mine is "As tight as you can then hit it up a half a turn" Hope that helps

 

[rmw]

Well, I hate to be called an old timer, but I was once formally trained in proper slugging wrench techniques. Beat up many of them. By the way you quickly learned not to miss with the hammer.

The determining factor was the stretch called for in order to obtain the clamping forces desired. Some quick math using the thread pitch of the bolt or stud determined how much rotation of the nut or bolt head was required after it was 'snugged' up. Now, that was subjective, what exactly was 'snugged up'?

Then a mark was made on the stationary part, the flats were counted and a mark made at the appropriate place on the rotating part. Then the wrench was slugged until the mark on the flat lined up with the mark made on the stationary part, where upon the required 'stretch' had been obtained.

Anyone who had done that a few times rarely required actually marking the flats unless the required stretch was critical. I don't think there was a 'rule of thumb' as much as there was just the experience of having done it. When swinging a 10 lb sledge, one didn't want to be too generous with extra 'strokes.'

I sure do love bolt heaters and torquing tools. We've come a long way baby.

rmw

 

[Ron]

Bring the bolt to a "snug tight" condition. Mark the nut and the surface below with corresponding marks. Turn another 2/3 of a turn....turn of nut method.

Snug tight is pulling hard with a spud wrench, so probably in the 100-150 ft-lb range.

 

[blfarrar]

Howdy

If you think about this it isnt far away from the technology of today that use angle as the criteria rather than a torque wrench.

Having had the classical education that torque wrenches were the only way to go....I found it alien to consider torque angle.
But when you think about it this excludes lube etc & stretches the bolt as needed, what the hammer aproach achieves is just a bit easier - physically.

What has to be considered is the material of the bolt, the type of threads (% location) some consideration of temperature of the assembly in use most importantly the yield point of the bolt
Umbrako did have an excellent slide rule calculator for small fasteners my engineering handbook has some data on torquing up.

Bruce L Farrar.
Works Engineering Manager
Marshalls Mono PLC.Brookfoot Works.
Halifax W.Yorks UK