Three reasons why *you* need a Japanese swordsmith’s hammer for forging knives.
- Size – the small face is better suited for working on a narrow target, keeping the hammer from hitting the anvil as the bevel gets thinner
- Weight – though the face is small, the long body carries the weight of a much larger hammer behind it, focusing the energy to better move tough carbon steel
- Balance – with practice, the balance of the weight forward design causes it to walk neatly along the blade while the hammer does most of the work for you
…and besides that, they just look cool. So if you are a bladesmith, find one or make one.
This one was hand forged from a length of scrap 4140 rod about 1.5″ in diameter and 6″ long (about 3lbs. according to Practical Blacksmithing p.267 – which is not in all editions). A fellow metal worker and aspiring smith, Anthony Rabideau, was over from the mainland a few weeks ago and assisted as the striker for the initial forming and punching work. The rod was upset on one end until shortened by about half an inch, widening the face end enough to form the octagon shape and still be left with a 1.5″ diameter. Anthony made a version of his custom combination slitter and punch from an old chisel to create the eye, and we forged an oval drift to open it up.
Yesterday I finished shaping and filing the face, then reheated the piece for some clean up forging of the sides and around the eye, hardened and tempered it, cut off the excess half inch above the eye, and then cleaned it all up with a sen and finished by draw filing. The face is a very flat 1 3/8″ square with diagonally rounded corners and the edges parabolic-ally rounded off to prevent marks. The head tapers down to 1″ by 1 5/16″ above the eye and the length of the head is 5 7/8″. The handle was hand shaped from an old axe handle and is currently 12″ long but may be shortened and tuned as I get used to the hammer. Sealed with a coat of pure tung oil.
Material: Scrap 4140 steel rod, reclaimed axe handle