I've seen some good deals on pneumatic jack hammers in pawn shops and was wondering...

Has anyone modified one of these into a trip hammer for forge work?

Yes I do have enough air to run a 90# jack hammer in the shop.

I have seen one used for punching holes through something like 50mm (2") square, but it was still hand held, no modification.

I prefer the precision and control of my hydraulic punching process.

Alan

Try it and report back.  I have seen videos of them being used forging hand held in Europe.  I think the biggest issue would be figuring out how to control it with enough finesse to be useful.  I have a 60lbs electric hammer and it is sort of an all or nothing type thing.  In my misguided youth we did use smaller "chipping guns" for all sorts of uses in the shipyard but again, hand held.

Edited June 21, 201511 yr by LawnJockey

Years ago remember seeing an article where they converted one.  Must not of worked that well or there would be a lot of them done that way.  If you are building do a Kinion style are hammer with an air cylinder.

IIRC, Russ Swider used them in his shop but I think they were hand held to drive drifts and do upsetting.  He would take a heat on the end of a bar then lay it horizontally on a large table against a backstop and apply the jackhammer to get plenty of upset in one heat.

IIRC, Russ Swider used them in his shop but I think they were hand held to drive drifts and do upsetting.  He would take a heat on the end of a bar then lay it horizontally on a large table against a backstop and apply the jackhammer to get plenty of upset in one heat.

I seem to remember something about that…I did try and use a little pneumatic hammer to do some upsetting and found it was okay-ish on 12mm -16mm (1/2" - 5/8") square  but it was not a great saving of effort by the time you had trued it up. Very easy to get wrinkles and folds and difficult to keep it straight. Rosebud torch and hand hammer with the bar held horizontally in the vice is the most controllable and efficient for me.

Alan

I have seen them used free hand, but I think it was more to show off than anything else. As the "throw" isnt that great i would think that somthing akin to a giant air planishing hammer might be the ticket. Think of a tradle hammer, using the air breaker as the hammer, push down on the pedal to bring the hammer down to the anvil, let up to raise. If obe fallows the planisher moddle, bowles out of 1/8" cold becomes doable. 

Search for videos with Jesse Sipola, his work is impressive.

Guys are using "jack" hammers for sinking and raising plate with good results. I'll have to ask on a list I hang on for links. IIRC one fellow does some really impressive repoussee and chasing with "jack" hammers and tooling. BIG and thick steel for large sculptures.

Guys have pedestal and stand planishing hammers and things "like" pullmaxs made with various size pneumatic hammers.

I'll ask around and see what I can find.

Frosty The Lucky.

 

Wasn't there one guy on here had plans for a doodad he called a Zipmax?  Basically a handheld pneumatic hammer mounted akin (but not exactly like) a power hammer?

Edited June 21, 201511 yr by Quarry Dog

About 20 years ago there were two articles about using a mounted jackhammer as a powerhammer.

What I remember is that: jackhammers were designed to be held loosely against the work and so a solid mounting did not work well.  One fellow used 90# spring as I recall to replicate the "belly of a bruiser hanging over the handles". Also they have very little throw so you have to have a very adjustable system to be using them in their sweet spot.

Or in other words building a tirehammer should be faster, easier, cheaper and work better.

I guess at this point, well, it was a curious observation but probably not worth the time and money trying to reinvent a square wheel.

Thanks to everyone for their input. I'll let this one die off.

The "treadle hammer" like assembly might have potetial, as you have adustibility to overcome the short throw and your using your weight to apply it to the work (or conversly to lift it off the work?) the air planishing hammers (they are hoped up air hammers and air scallers) use n adustible anvil (somthing like a 1 1/2-2" bolt with a big hand wheal) to deal with the throw issue. Just scale it up. 

First off there are a number of air hammers that are of use forging.    True Jackhammers, chippers and scaler's are probably the least useful.    What is useful are the large (and small) rivet hammers.      Chippers and jackhammers have a on/off switch,  Rivet hammers have a throttle you can feather to get slow, soft blows

 

Grant had a 100 lb air hammer built from the hammer on the back of a IR 52 upsetter.     There is a video of it on youtube.    I tried to post a link and it said I didn't have   permission

Virgil England did an article on such a hammer in Blade magazine years ago. He called it "The Arctic Rattler" and used it for raising armour, or as a planishing hammer.