Treadle hammer

Dale Peters · December 4, 2007

Another can crusher is born. I finished my treadle hammer this weekend. The hammer assembly weighs about 80 lbs. The anvil is a piece of 7-inch round on top a piece of 4x6-inch 3/8-inch wall tubing. It may not be as heavy as it should be, but I think it

Ian · December 4, 2007

looks good Dale, does the bar that actually pulls the mechanism down move or is it fixed? I ask because the guide system obviously makes the head go straight up and down. The usual slight lateral movement on the top tup you get with a normal oliver type treadle hammer has been eliminated on this design (good idea) so the linkages must take up this movement but it's not clear where on the photo. Care to fill us in? All I can see is a link from the top beam of the hammer down to the bottom of the bar that pulls down the ram, does that move?

Jacob · December 4, 2007

Nice. I'm currently collecting parts and ideas for a similar one. I'm planning on using a square hole in the hammer and anvil, with a wedge to hold tooling in place. It looks like you have the room underneath for a wedge, but no hole. Are you planning on using bolster plates or something similar to clamp onto the anvil/head? You're alignment system for the head looks different than others I've seen online, too. I'd like to see another picture or two. I'm currently thinking of using the roller blade wheel guide, but I have access to a mill for cutting alignment slots.

Marc · December 4, 2007

And here's another guide method. It's so interesting to see how one set of plans can be altered to suit whatever's on hand.

I used the tube-in-a-tube, but my bearings are 1" UHMW round rods tucked in some pipe 1/2-nipples. The bolt in the pipe cap is used to adjust the UHMW rods. For lube, I used some Teflon/Silicone lube squirt. That stuff is pretty slick.

Jmercier · December 4, 2007

I didnt build this hammer myself, I purchased it from another smith who was selling it for a friend of his who had built it and never got the chance to use it before moving across country, but here is a picture of how my hammer is setup. I need to make a flat die for the bottom still, the top is also removeable with a wedge, and there's a square hole for bottom dies in the anvil.

Dale Peters · December 5, 2007

Thanks for the comments. I've enclosed more photos to help explain how I built it.

Ian, the rod swivels at both ends. The threaded rod at the top adjusts the height of the hammer over the anvil. It's 3/4-inch by 12-inches so there's plenty of adjustment. Some people use a commercially made adjustment wheel (the correct name escapes me at the moment), but I'm cheap so I built my own. The clevises and the swivel are all cut from heavy duty rectangular tubing.

Jacob, the lower die has a 1-inch square bar welded to it and it slips into the die holder. I'm hoping it stays in place without any additional work. As you can see from the photo, I welded four pieces together, then to the anvil to make the die holder. It fits snugly and doesn't move much. If it doesn't stay in place I guess I could drill and tap a hole in the side for a set screw.

evfreek · December 5, 2007

Hi Ian. Good question. I was puzzling about that one myself. If you look at the straight linear path that the head moves from the up to the down position, the arm pulling the hammer head forms two legs of a triangle with the linear path of the hammer as the base. Therefore, it must change in length as it sweeps out the path, or else the hammer would have to move in a circular arc whose radius was equal to the arm's length. Since it is constrained by the guide, it moves in a straight path. The slight deviation of the paths means that the arm must change length during the stroke.

Note that it must only change length if it remained straight. I suspect that it bends slightly, since it appears to be made out of some kind of leaf spring material. I have seen such designs with rollers on the actuating rod joint, but I think that this design takes the slop in the bending of the arm.

Dale Peters · December 5, 2007

The arm is a leaf spring and may flex some, but the pivot point at the back end of the spring and at the bottom of the support bracket (attached to the top cross beam) acts like an elbow joint on an arm. As the hammer is pulled down, the pivot point draws back (closer to the support column) and forward again after the hammer passes the center point of its path downward. I found that the push rod bracket had to be past a certain point (closer to the hammer) or it was impossible to lift the hammer with the springs. I'm not very good at explaining things, so I hope this explanation doesn't confuse the issue.

I was lucky the leaf spring had an "eye" on one end. It made it a lot easier to attach it to the hanging bracket.

Marc · December 5, 2007

Dale, I wish I had thought about your method to make the square tool hole when I made mine. I cut four corner holes, then used a hole saw to cut out the middle. Then a lot of filing. The thing is, I've used that method to make square holes before. There's something about the memory being the first thing to go, but I don't remember what it is.

In case Dale's explanation about the arm pivots isn't totally clear, let me try to muddy it up. If you look at his first picture, in the message that started this, you'll see that the left end of the spring/arm is pivoting on an assembly that hangs down from the top horizontal support arm. That assembly also pivots at the top. So when the hammer comes crashing down, you will see the left end of the spring/arm swing in and out while that vertical assembly swings left and right.

This is basically Clay Spencer's inline treadle hammer design. I bought his plans and found them to be a great resource. I strayed from them quite a bit, sometimes because of what I had on hand, others to "tinker", but the basic measurements and operation were very useful. Someone cleverer than me could probably just look at the picture, though.

Some improvements I tinkered with:

Springs - I use just barely enough spring to hold the ram to its top resting spot. Then I connected a real short, maybe 4", spring with a chain. That spring only comes into action at the bottom of the ram's travel to give it an extra boost for the return. This makes for an easier push down and less energy, but still a quick recovery for faster blows. Bruce Freeman, of Grasshopper fame, suggested this and calls it a "kickback", I think.

Guide - I mentioned it above, but I used some UHMW as bearings. I got a 4-ft rod from eBay for about $10 after shipping. And if you look at the hammer head closeup I posted above, you'll see what looks like hockey pucks. They are indeed hockey pucks with holes drilled in them. I use them as bumpers for when the ram returns to the top.

Hammer - I kept it light, at 35 lbs. My reasoning is that a heavy hammer takes too long to return, unless the springs were real strong. Since I mostly work in small stuff, 5/8" and smaller, I didn't feel I needed all of 80 lbs or so. And since a whole lot of work was done in earlier times by a striker with a 16-lb sledge, I think my 35 lbs is sufficient. I used it to make a hand hammer and it performs very well in punching the eye and forming. I even upset the 2-1/4" round 4140 to get the length/weight ratio I wanted. I gave up a whole lot of sweat making this, but energy is energy. No matter what hammer weight you use, the end result is the work you put into it. More blows with light, or less with heavy, as long as the hammer mass is up to the task, it will probably turn into a similar amount of work on your part.

Treadle - I curved a piece of 1-1/2" pipe for mine instead of fabb'ing one. That's just because I thought it would be cool. One could argue that it lets you stand at any angle, but it really doesn't make a difference. However, the tinkering thing I did was to connect it to the connecting rod using a leaf spring bent in an elongated "C" to make a shock absorber. The TH's I've tried had too quick of a stop at the end for my aging knees. The ram's arm is a leaf spring, but it's too short to absorb enough shock. This added C-spring feels nice to me. It does add a little response delay from when you press down, but that was easy to get used to. And on small, repeated, blows, I can get a really nifty rhythm going.

Bottom line on this project - I've said it before and will probably say it again, but the only thing I'm disappointed with on my TH is the time it took for me to get it done. I use it almost every time I'm forging. As a third hand, it's now become indispensable. For bigger work, it's no power hammer, but for a part-time hacker like me it's so much better than a hand hammer. Drawing, spreading, and cutting are done in 1/2 to 1/4 the time, saving heats. It lets me spread the work around the different joints in my body instead of just my elbow and shoulder. For a tool nut like me, just building it was fun and rewarding. And it really does a great job on cans :)

Dale Peters · December 6, 2007

Marc, I also had to use a kickback spring. You can see it in the first photo. Even with four garage door springs, there wasn't quite enough "oomph" to pull the hammer back up. The extra spring is enough to get it started back up, and like yours, it doesn't come into play until the hammer is near the bottom of its stroke. It doesn't take much effort to get the hammer moving on its downward stroke.

As far as the weight, it is probably heavier than it needs to be. The main part of the hammer is only 40 lbs, but by the time I added the extension, the rods and the die holder, it gained weight pretty fast.

I like the idea of using a leaf spring as a shock-absorbing connecting rod. I'll keep that in mind in case this one is hard my joints. I'm no spring chicken anymore.

This evening I started on building fullering and flat dies for it. While the flat plates you see in the photo might be useful for cutting and other hand held tooling, they're especially good for crushing cans. There's enough room for squishing three at a time.

I also plan on making some hand tooling. If anyone has any suggestions for tools they use a lot, I'd appreciate it.

Sam Salvati · December 6, 2007

Get a section of pipe, weld a cap to one end and weld it to the side of the anvil, and keep the "often used" tools in there, like a straight hot and cold chisel, center punch, hot cut(along with a cap to go over the bottom die to protect from the hot cut marks, made from copper or brass or mild steel).