Choosing a Chasing Hammer
V1.0 © Brian Meek. All rights reserved.
A selection of chasing hammers. Ranging from high quality to low from left to right.
Chasing hammers are odd ducks. Every other hammer is intended to contact the work directly, so the most important parts of it are the faces on the head. The handle’s just there to help hold onto it. Chasing hammers on the other hand are intended simply to be the driving force behind the chasing punch that’s doing the actual work. In that sense, the nature and shape of their heads is largely irrelevant to the work. Weirdly, the most important part of a chasing hammer is the handle.
The head on a chasing hammer has a very large, flat face. The reason for the big face is to make it easy to hit the back of a chasing punch without paying too much attention to it. When chasing, the jeweler’s attention is focused on the working end of the chasing punch. It would detract from the work to have to spare part of the mind to worry about accurately hitting the back end of the punch, so the heads have very large faces to make it easy. They also tend to be very heavy in proportion to the thickness of the handle. The handles of good chasing hammers look positively spindly in comparison to the handle of any other type of hammer. The reason for this is simple: the handle’s a spring.
Other kinds of hammer rely on a strong handle to channel the energy generated by the shoulders through the hand and out onto the head where it can be slammed into the metal. They need to be stiff and strong to survive that sort of treatment. In aid of this, they’re usually made of hickory wood, which is very strong, and very rigid. Raising, forging, or other metalworking operations rely on a limited number of hammer blows driven by the full arm and shoulder of the worker. Heavier heads aid in delivering more energy per blow, but most of the energy is coming directly from the major muscles of the worker, in a series of slow, powerful blows. Chasing hammers work differently. Instead of relying on slow, powerful blows, chasing depends on a fast succession of light blows, sometimes as quickly as two per second, for minutes at a time. The full arm can’t move that fast for more than a few cycles. The way chasing hammers are used is to hold them in the hand and flick them at the back of the chasing punch. The power comes from the hand and wrist muscles. These muscles aren’t intended for that sort abuse, and won’t take it for long at maximum output. What actually happens is that the hammer head is flicked at the back of the punch, and the weight of the head itself does most of the work. The springiness of the handle is critical in cutting down on the amount of energy required to keep the head jackhammering into the back of the punch. When the head hits the punch, the head stops, but the inertia of the hand keeps the hand moving forward, flexing the springy handle. The spring energy building up in the handle slows down the hand, and helps it reverse direction for the backstroke, saving the energy that would otherwise be required to get the hand stopped and moving backwards. At the end of the backstroke, the arm muscles stop the hand, and get it moving forward, but the momentum of the hammer head wants to keep going backwards. Again, the handle flexes, forming a spring. Once the head stops moving backwards and begins moving forwards, the energy that was just stored in the flex of the handle accelerates the head forwards faster than the motion of the holding hand. With a properly springy handle, the hammer head reaches maximum forward speed just as it slams into the back of the punch, moving more quickly than the hand that threw the blow, thanks to the stored energy from the flexible handle. The reason this matters is that impact energy is exponential with speed. (I=.5*MV2) So even a little bit of extra energy from a springy handle is enough to make a difference. Good chasing hammers also have fairly hard steel heads. This makes the heads springy as well. When the steel head slams into the back of the steel punch, there’s an elastic rebound that helps throw the head backwards. With the material of the hammer manipulated to form a set of labor reducing springs, a good chasing hammer helps make chasing much easier than it would otherwise be.
The problem is that good chasing hammers are getting harder and harder to find. Largely because the buying public doesn’t know what to look for in a good hammer.
The most important element is the handle. Most hammer handles are made of Hickory, a very strong, stiff, tough wood. Chasing hammer handles are traditionally made of fruit woods such as apple or pear. These woods are neither strong nor stiff. What they are is springy, which is exactly what’s needed in a chasing hammer handle. Good luck finding one of those short of making your own. However, it is possible to get chasing hammers with very thin handles made in a wood that I don’t recognize (not being a woodsmith). It’s not hickory, but neither is it apple. It looks almost like Ash, but I’m far from an expert. (The first three hammers on the left above are this wood, whatever it is.) The big issue with these (and applewood handles, should you ever see such a unicorn) is that they be thin. The thinner and whippier, the better, so long as they can survive being used. The leftmost hammer above is the only properly sized chasing hammer handle I’ve come across in the past 15 years that was for sale, and even that was as a replacement. Fortunately, I got a good head to go with it, and put together a very nice hammer. I scrounged the handle out of the back bins of a tool dealer in London’s Hatton Garden. Lord only knows how long it’d been hiding back there. The second and third hammers from the left above are more typical of ‘good’ hammers today. The red-and-silver one is mine, the other one belongs to the Wake center. You’ll notice that mine has a thinner handle. It arrived looking very much like the school’s. I used files and sandpaper to shave down the handle to a thinner, snappier incarnation. There’s no reason not to do that, and it seems to be the best way to get a decent handle these days. If you do that, be careful to transition gently from the reinforced section under the head, into the thinner ‘spring’ section, and back out at the bottom. If you create sharp transitions, they’ll concentrate stress, and make that area more likely to break. Look at the transitions on my shaved-down handle. One final thing to note is that with handles this thin, chasing hammers cannot take being used like normal hammers. If you try to swing them with the full force of your arm, the handles will snap in seconds. They’re intended to be used to flick the head into the back of a punch. The weight of the head does most of the work, not the hand pushing the handle. If you put too much energy into the handle, you’ll snap it. Keep that in mind.
All of the hammers have what’s known as ‘pistol grip’ handles. I prefer these, as the asymmetry makes it easy to keep track of the orientation of the hammer head by feel alone. There are symmetrical oval handles, but they make it harder to keep the head oriented without looking at it periodically. The handle of hammer #6 is almost an oval, to the extent that it’s anything.
Having mentioned the good handles, it’s time to talk about what you don’t want. The three good handles above all came with either German or English hammers. The three on the right are from India, Pakistan and points unknown. I have seen some decent hammers come out of Asia, but equally, I’ve seen loads of crud. These are definitely in the latter category. I’m not sure what the wood is, but I’ve seen all sorts of Asian hammers with handles made out of it, whatever it is. It’s very tough, but not especially springy. The biggest issue with the handles comes from the shaping. Notice the good English handle: it’s got a long center section of equal thinness for a spring, and gentle transitions into and out of that section. Note the shaping of the cheaper handles: they’re much thicker, even at their thinnest point, and it is a point, not a sustained thin section. So instead of the whole thin section flexing, these handles will flex only in that one thinnest spot if they flex at all. Note the sharp transition under the heads of the innermost two of the cheaper handles. This will concentrate stress at that point. In use, these handles are so stiff they’re essentially clubs. There’s no flex or snap to them at all, and chasing with them for any time is a chore.
Top view of the hammer heads, showing the sockets.
The cheap ones are on the left this time.
As I said above, the handles are by far the most important part of a chasing hammer, but the head isn’t totally irrelevant, especially the socket by which it hangs onto the handle. Good sockets are oval, to keep the head from spinning on the handle shaft. They also taper from top to bottom, to keep the head from flying off once wedged in place. Speaking of wedges, proper handles are fixed in place either with wooden or metal wedges. Sometimes both. Either way, it’s critical that the hole in the head be an oval. In the image of the hammer heads above, the astute observer will note that the two cheaper hammers on the left have round holes. This means the heads are always spinning around on the handle shaft. Totally unacceptable. The leftmost hammer is one of those ‘mystery hammers’ that turn up from time to time any school shop. I’m not sure where it came from, but it appears to have been manufactured originally with those three brass nails in the head by way of an attempt at a wedge. There’s no trace of a proper wedge, or the slot it would have left behind. It looks like it really was made that way. Needless to say, this hammer spends most of its time in the back of the junk drawer. On the second hammer from the right, that round ring wedge is a European style. They work very well, and are a good thing to see.
To wrap up, the most critical thing to look for in a chasing hammer is the handle. Ideally, it should have a long thin spring section, with smooth transitions. It should be of whatever that light blond wood is, rather than the unknown dark asian wood, which is too stiff. I prefer pistol gripped handles. If the handle arrives too thick, don’t hesitate to shave it down. As far as heads go, a 1” diameter head or larger seems to be the right size for most things. 7/8” heads are surprisingly small and delicate. Most importantly, make sure the handle socket is properly oval, and the handle is well fitted. If at all possible, try to buy your chasing hammers in person, so that you can pick out the best of the litter.