treadle hammers

[keithh999]

I have seen several types of treadle hammers pictured in the gallery and was wondering if there is any difference in applied force if the lever action is applied internal of the main support and the anvil or external of the main support??

[keithh999]

im guessing noone has an answer or input???

[larrynjr]

I'm no kind of mechanical engineer to have an answer but I know others here are.
Possibly a similar question has already made it the rounds and they are waiting for you to find it in the archives or they haven't had time to fomulate an answer.

[John B]

I would think a lot would depend on pivot points and leverage ratios, and how efficient it is. I personally prefer one with internal connections as it takes up less space in the workshop

[Mills]

I'm unsure of what you are asking. To keep things in perspective there is not a correct answer to how to build a treadle. Consider ApprenticeMan's treadle and the Clay Spencer version then look at the Grasshopper. I have used both a swing arm and a grasshopper and while the GH is really neat, it is not worth the trouble. No real gains over the simplest of hammers. Friction is the real issue. However your mechanism operates, it needs to have the least friction in the system.

For example, I considered using a counterweight on an eccentric to reduce or eliminate springs. An engineer helped me with the design considerations and pointed out that unless I came up with a monomer strand (honking big fish line) there would be too much friction in the rope itself, aside from the numerous pulleys. Neat idea that did not work with real materials.

Thus if your design has bends and elbow then these will flex reducing the applied force. Not a good choice. if you are mounting your mechanism inside a tube but other than that it is straight lines and springs, you should be alright.

KISS

[keithh999]

i guess what i was asking/ inferring was would the hammer have more applied force if the main arm was pushed down with the external arms or pulled down via the internal arms??
thats pretty much the only way i can describe it as i dont have a treadle hammer but am considering building one with all the free stock i have available....just want more bang for my buck so to speak..LOL

[HWooldridge]

I built mine to the original ABANA plans that were put out 20 years ago or thereabouts. Not much adjustment, swing type 60lb head and about 24 inches clearance at rest. It hits very hard and I never make adjustments to it but instead, try to tailor the work and the tools to fit inside the sweet spot of contact. This area starts about 8 or 9 inches above its anvil. Higher than that and I have to assist with one hand to get a really hard hit but I don't have many combinations of tooling that are that tall. I'm not knocking any of the newer designs but the old ABANA plans will make a good hammer.

To answer your question, steel works best in tension - not compression, so in most applications, it's always better to pull than push.

[ThomasPowers]

Also as was mentioned above lever arm and piviot ratios control how the energy you put into the system gets used.

[Ken Kelley]

So with every added complication, i.e., straight line hammer as opposed to the swing type you are introducing mechanical "disadvantage" to the system and reducing efficiency. I would like to build a treadle hammer for the primary purpose of drawing out pattern welded billets. It sounds to me as if the swing type hammer would be admirably suited for this task? And simpler to build in the bargain.

[Marc]

Yup, basically I would think that you do the simple physics lever calculations between the treadle and arm, and then maybe subtract for friction. So a basic swing arm, Oliver-type, would probably be the most efficient, as there would be fewer friction points.

Personally, I like the inline, mostly because I've gotten accustomed to top tools and a swing-arm could need adjustment for different heights.