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My hammer was inspired by Bruce Freeman, New Jersey Blacksmiths Association. Bruce researched, designed and prototyped the Grasshopper Treadle Hammer. After seeing his wooden model I was determined to build one. Although there are some major differences between Bruce's design and my modification of his concept, they are essentially the same in terms of the mechanical movement of the device. Bear in mind, this hammer is a "straight-line" motion hammer. As far as I know, the first of it's kind. Most treadle hammers have an arc-line motion. This is fine is you want to use hand held top tools. The major benefit of a straight-line motion is, like power hammers, die sets can be attached to the hammer and anvil freeing one hand and assuring an "on center" blow. The "grasshopper linkage" was used on early steam engines. One of the most appealing aspects of this type device is the simplicity of it's fabrication and maintenance. I used a single 3/4" plate as the frame of the hammer. I did so because it offered great strength, allowed for a thin, obstacle free area around the throat. After cutting to shape I needed only drill (2) 1"ø holes for the radius arms connectons. |
 | So, instead of having a single set of arms and a double frame, I have a single frame and double set of arms. The arms are all 1/2" x 2" flat bar. All the pivots have oil impregnated bronze bushings in them. Most of the pivot pins are actually 3/4"ø x 4" grade 5 machine screws with heavy duty NyLoc® nuts. All these parts are commonly found in most iron shops. Additionally, no machine shop work is needed to build this hammer. I used only:
The 6"ø anvil stands 30" high. The hammer is 4 1/2"ø and weighs approx. 120 pounds. A section of 4" pipe was welded to the top of the solid hammer section to increase it's length to make the connection to the hammer arms.Since the hammer connections weigh at least 10 pounds, I call this a 130 pound hammer. This hammer uses only HALF the potential stroke of the grasshopper mechanism. Bruce Freeman and Marshall Bienstock have built a double framed grasshopper hammer that employs the full stroke! |
 | I was able to achieve sufficient space above the anvil (13") by using 3' hammer arms. With Bruce's design, the overall depth of the hammer can be shortened by using shorter arms and the entire stroke. Although the photo to the left shows the hammer in the down position, it actually travels further downward to strike the bare anvil. This is achieved by a slotted joint (center pin) in the treadle. I plan to use anvil and hammer dies so the effective stroke necessary will be less than the hammers capacity. The diamond plate treadle pedal was a left over from a previous design and will probably be reworked. I'd also like to experiment shifting some of the springs from the top set to the treadle. This position seems to be more favorable. |