Friday, August 31, 2012

Helve Hammer Part 1

It was around 1999 when I took a trip out to visit my friend Wray Schlelin out in Massachusetts that I started forming the ideas for my Helve Power hammer. Wray had built a Helve hammer quite a few years before that to support his home based metalshaping business. He builds replacement sheetmetal parts for old Jaguar 120's and 150's. His customers are high end restoration shops and avid Jaguar club members that are rebuilding their rotted out barn finds. He supports his family from this work alone. I met Wray over the internet. I can't quite remember the situation but I think it all started with a article he did for Artmetal on the art related uses for the English wheel and some of his innovative tools and equipment.

Wray got part of his inspiration for a Helve hammer from a tiny little picture he found in a magazine or book. I'm pretty sure this is the picture below that got him started building his own helve hammer.
This is the helve hammer Wray built with only a tiny picture and some motivation. His hammer has been used regularly for something like twenty years or more. A testament to its construction. Its amazingly quiet. You can easily carry out a conversation standing next to the operator. Not much of a picture to go on but it was enough. Below is a video of Wray's hammer in action.
The origin of the Helve hammer goes back to ancient Chinese and Roman times. There are drawings of water powered trip hammers that are basically a Helve powered by a water wheel or bunch of young indentured apprentices. Helve means handle or shaft much like the handle on a normal hammer or an axe handle. They swing in an arc like the natural swing of a human but with a lot more endurance. This distinguishes Helves from other types of power hammers like Little Giants (below) and big Yoder type hammers which are both called guided way hammers.This means they can have both top and bottom dies that meet in a precision way to perform special work.
There are two distinct end uses that determine the construction and accessories for Helve type of power hammers. One is forging like you would see a blacksmith do where the metal is heated and worked red hot. The second type is the type I was interested in building which is for compound sheet metal shaping.The work material is much thinner and the material is worked cold.
Above is a picture of a monster Yoder hammer, probably from the aircraft industry. These are massive tools generally outside the hobby type user. I don't think you could run this in your garage at home and not have your neighbors coming out with pitchforks and torches to kill the monster. These are heavy duty industrial tools and are as scarce as moon rocks.
The simplicity of the helve hammer immediately appealed to me and my sense of design. Its just like hammering with a normal hammer but without the bursitis and sweat. I was interested in compound metalshaping but not all the heavy hand hammering physics lessons. This picture of a big Bradley forging helve is an example of a hot working helve hammer.

After seeing what was possible and being highly motivated after my trip back east I started my helve project in earnest.
An early design study. At this point I was thinking along the lines of a counterbalanced mass parallel action hammer. Not a true helve but similar.
This is a scan from one of my design notebooks. This is starting to show the final layout and some of the major design elements of the helve hammer. Note the curved arm on this study. My thinking on that was I might need additional clearance under the arm for deeply formed shapes. As it turned out I abandoned that idea when I looked at finding a chunk of quality hardwood big enough to cut that out of.

Another early design sketch. Here I was still contemplating an air cylinder as my power source. This is pretty close to the final layout. The major point here is that the construction method for the signature piece of a helve has been decided. At this point Its important to mention that I switched to a CAD system to do a more detailed layout and start the real mechanical design work.

Stay tuned for the next installment.

1 comment:

  1. Tom...

    Just had to copy and paste, then send to my good buddy, we worked together in a auto shop together....he will be spitting his teeth out laughing as was I....great story!

    Chuck

    ReplyDelete