trip hammer questions

Before I found my LG, I built a treadle hammer. It has a head that weioghs about

180 lbs, held up by a coil-over motorcycle shock that leaked all its oil out. I set it up to swing out over the anvil in use. It sure makes things flat. It shakes the whole building and the neighbor says he can feel the ground shake when I use it. The head is a chunk of three inch thick plate welded to a length of four inch pipe filled with lead and slung from a vertical support by spring bars that I had fabbed at the local spring shop. The shock clamps to the upper spring bar and rests on the vertical support, like an abbreviated independent front end suspension. Linkage goes down from the lower spring bar to the pedal that's hinged to the bottom of the vertical support. By moving the clamp along the upper bar, I can adjust the rebound height from the coil spring on the shock, and adjust the coil spring preload with the step adjuster that came with it. The whole thing is bolted to the building frame with some really big U-bolts I got off a Big Rig axle and sits on an oak block to keep it from driving itself into the concrete floor. Converting it to power would entail making a crank and connecting rod assembly and spinning it with an electric motor through some sort of gear-down tranny. But... since I have the LG, it seems to be a lot of bother to motorize it. It still gets used from time to time to straighten out billets, and as a third hand clamp on the anvil. Hope this gives you some ideas...

Charly

I've built both of Clay Spencer's hammer plans. One is a swing arm (head / arms / column form a parallelogram) that I built one of and the other is an in-line head that I organized with some others and built either six or eight of. The in-line type uses a piece of steel shafting for the head and it runs in skate wheels, so it always moves straight up and down.

Clay's plans are excellent. All the detail you need, and not too much. You can get them several places including Norm Larson ( snipped-for-privacy@impulse.net).

Charly's approach sounds interesting, but I bet it has a pretty slow repetition rate. On the other hand, you probably only need one whack. A friend of mine attached a sledge hammer to the overhead beam with a bunji cord. He said it worked pretty well.

Steve

theChas. wrote:

I forgot--Clay's heads weigh around 60 pounds.

Steve

theChas. wrote:

Actually, it rebounds pretty fast. I can get in about three strokes a second average with my 'kickstarting' leg. It does have a fairly short stroke length, about six inches,which helps the cyclic rate. The roller bearings help too, less drag in the mechanism.

Charly

Pretty "impressive" Charly. Roller bearings make a lot of sense.

Steve

********* 'kickstarting'??? Does that mean you use your toe to assist the spring, in the 'lift' stroke? charlie

No, it means that my right leg is significantly stronger than my left from kicking the bike all these years. "Electric starter? What's that? Oh, that ugly little motor that ruins the lines of the primary case? Don't hold with 'em, Just a bunch of useless extra weight".

Charly