Construction my my helve came about when Stan Carter offered to swap a "hammer kit" in exchange for a set of measured drawings to help others build their own hammer. This is a picture of the kit that Stan provided, it included all of the metal precut, the acme screw and nut, heims, the toggle spring and even a set of dies and work table. Building it was like falling off of a log at this point.

Here is a close up of the the sliding bracket, as built by Stan Carter (after a quick visit with the bead blast cabinet). You can see it is a fairly simple construction, it gets the job done with the minimum amount of fabrication and is a nice package.

Stan lives in the Mojave desert, and has an amazing collection of raw materials. If Stan hadn't taken the time to gather up the parts and do the initial fabrication this would have remained a back-burner project for me for a lot longer. That would have been a shame, because this is a really useful metalshaping tool that is within the reach of ANYONE.

The first thing I did was to clean some of the desert patina off of the parts, lay them out and make a list of what else I needed to get. I already had some round bar stock in the shop to use for the toggle pivot, eccentric shaft and coupling rod. I needed to get some pillow blocks, two each in 1" and 1/2" sizes. Northern Tool is a good source for these, they seem to be cheaper than anyone else around.

I also needed a 1/2" pneumatic drill, which I got on eBay for $40. Northern Tool carries them for about $60, and they are sometimes on sale for even cheaper. I needed a pneumatic foot pedal, another eBay find for a whopping $20. A trip to The Hose Shop in Santa Cruz got me two pieces of air hose and some fittings. With all of the parts in hand I was ready to get started building.

The first thing I did was to weld up the stands for the toggle arm. These are built out of 2" x 3" x 1/8" wall rectangular tubing. I drilled the angle cut parts so I could bolt the 1" pillow blocks to them, then welded the two parts together.

Next I welded the tool post support tube to the base so I could determine roughly where the supports for the toggle are needed to be.

To make the toggle arm I drilled a 1" hole through one end of the 2" x 2" x 1/4" wall square tube, slid in the 1" round bar stock and welded it. Don't forget to put the spring bracket on the toggle arm before you weld the die holder onto the other end! Here you can see the construction of the back end of the toggle arm. I also welded the die holder onto the other end of the 2" square tube.

Once the pivot mechanism was assembled I could position the toggle supports onto the base. I double checked the alignment of the toggle arm and die holder, checked that the toggle arms were square with the base and welded them to the base.

With this done, the only remaining work was to mount the air drill and build the linkage to connect it to the spring. I started by building the eccentric. You can do this a lot of different ways, I tried to do this in a way that didn't require any fancy machine work. The key dimension is that the eccentric has a 3/4" offset, center-to-center. I laid out a 1/2" hole for the drill shaft and a 7/16" hole for the heim bolt. The 1/2" rod for the drill shaft was chamfered, and welded into the 1/2" hole.

I mounted the second set of pillow blocks, the ones with the 1/2" center hole, onto a piece of rectangular tubing. I mocked up the eccentric shaft so I could make the coupling rod. I made this linkage using 3/4" round bar stock. When I mocked it up I decided that I needed about a 1/2" of offset from the eccentric to ensure that the heim didn't crash into the eccentric. I welded a piece of 3/4" bar stock, drilled with a 7/16" hole, cut 1/2" long, onto the eccentric.

Next I made a yoke to weld to the other end of the coupling rod. You could buy a pre-made yoke for about $10, I didn't have one and didn't want to wait -- so I just machined one from some 1 1/2" bar stock.

That pretty much completes the linkage. The air drill is held to the rectangular tubing with some hardware store u-bolts. I welded some steel blocks to the side of the tube to support the drill so that when the u-bolts are tightened they don't bend the eccentric shaft.

The entire "powertrain" ends up looking like this:

Before I could try this out, I had to plumb the foot pedal.

And I was finally ready to try the hammer out and make some noise!

Please use extreme caution with this tool, it has a lot of force and the movement of the arm could cause severe injury if it happened to smack you in the face.. Bolt or clamp it to a heavy base, and treat it with respect like any other power tool.