Altering a chasing hammer for ergonomics
By Charles Lewton-Brain
Many jewelers and toolmakers have forgotten that the jeweler is supposed to modify tools for his or her own use. Changing a hammer handle, engraving tool, or hammer face used to be standard operating procedure—and one of the key reasons to do so was to improve the ergonomic use of the tool and adjust it to your own body and usage patterns.
I know a famous chaser who cannot chase anymore because his elbow is damaged. I believe this damage was caused in part by his hammer angle, as well as the way that he grasps the hammer in his hand while using it.
A straight hammer requires you to hold your elbow up in the air when chasing, which is a real strain. There is an easy way to alter chasing hammers for ergonomic use—but first you have to be prepared to alter your method of chasing and adopt a Scandinavian approach. Hold the hammer with only your forefinger and thumb. It pivots, balanced, so that you don’t have to use your wrist much. This is vital, as actually gripping the handle and moving the wrist is damaging. Instead, a slight rhythmic motion rocks the hammer, and there is almost no work involved in using it on chasing punches.
This is why professional chasers have so many different sizes of heads on their chasing hammers. The weight of the head does the work, not you. You find the balance point in the hammer and set up a regular, slight movement of your hand. You aren’t grasping the handle, but rather allowing the fingers to be the pivot points. Using this technique, you can chase all day without a problem. I was taught to use a little talcum powder (corn starch these days) to reduce friction where the fingers grip the handle.
Here’s how you can alter your chasing hammer in a few easy steps:
1. Begin by cutting the handle off the hammer right below the head.
2. Reshape the extra thick wood at the top of the handle using rasps, files, a belt sander, or an angle grinder. Fashion an angled peg that the head can fit onto, placing the flat striking face between 6 and 8 degrees to the handle. Wedge the head on and epoxy it into place.
3. Once the epoxy has set, cut off the top back end of the handle at an angle. This will allow the hammer to pivot and swing more into the palm during use.
4. From the end view, slice off the handle material at the angles shown.
5. Blend the surfaces, rounding them and making them comfortable to hold. In this image, you can see how the surfaces have been blended and where the finish on the handle is worn thin and pale from use. The word areas are where the thumb and forefingers touch the hammer, allowing it to pivot and rock. When filing and sanding, continually test the swing and balance so it feels comfortable.
6. When the broad shape is comfortable and the hammer can move easily between your thumb and forefingers, use sandpaper and smooth it. The smoother the handle is, the better. You can use tung oil on the handle or dip it in double-boiled linseed oil and let it hang to drip dry, repeating this process until the surface builds up. This can take three weeks or longer.
At the end of this project, you will have a beautiful, comfortable, ergonomically correct chasing hammer that pivots and swings without must wrist action—and you’ll realize that you need more hammers with different size heads. So repeat the process on as many chasing hammers as you need. The actual time required to reshape a hammer handle, especially if you have some power tools, is only about an hour. Happy—and healthy—hammering!