A treadle hammer is a foot operated mechanical hammer. Think of it as a third hand or having a striker around that you don't have to pay. (Isn't that what the Pup is for?) It is not a power hammer, nor is it a hydraulic press or a fly press. It will do things that other tools won't do as well and there are things that they will do better than a treadle hammer. I have an anvil (actually several), a power hammer, treadle hammer and a hydraulic press. I would not be without any of them but then, I'm a blacksmith.
Yes, you can adjust how hard or light it hits, it just depends on how hard you push the treadle down. You can do very hard blows, harder than you would ever do with a hand hammer.
I have lots of dies but will be keeping them to use on the treadle hammer in my shop. I can give you lots of ideas about dies that you might want to build.
Rather than having a slot like some presses it has 1" square "hardy holes", top and bottom. All of the tools for my TH fit my anvils and press. (my press is set up more like a fly press than the knifemaker presses.
The ram on this TH is about 75#. I would not advise installing a heavier ram because the ram is raised by springs. If you had a heavier ram you would need stronger springs. Then it would take more energy to depress the treadle. The ram needs to just "float".
The next event at Tannehill I will be attending is the first weekend after Labor Day in September. It is the AFC's Blacksmithing Conference. Come on up, you will enjoy it. Remember the RR Spike Knife that Raymond Head had in the Spike contest at Batson's? The guy that taught Raymond how to make that is going to be one of the demonstrators, so maybe there will be something that you can learn about knife making. Or just stuff that you might enjoy. Cost of the conference is $30.00 but you have to be a member of AFC ($20.00 a year) so just figure $50.00 for the conference and you get the newsletter for a year.
I'm not sure about the overall weight but I think that it is about 700#.
There are lots of options for a power hammer. About the cheapest and a good way to go is the "Tire Hammer". Clay Spencer and John Wayne build them for 2 and a half times as much as the treadle hammer ($2,500.00).
Did I answer everything?
As I said above, it is not a power hammer although a lot of power can be delivered with it.