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I Forge Iron

Test run of my new power hammer

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I finally got my new power hammer wired! This is its first run. It was built by the same cousin who built the hydraulic forging press. It's a modified Appalachian "Rusty" helve hammer utilitizing a spare tire clutch. Very little new material went into making it. It has an 80 pound ram and is running dies made from railroad track caps. More dies and a different die holding system in the future.

The test piece of steel is about 5/8" automobile coil spring.

The Hausmann Millworks mentioned in the video is the creative community where my shop is located, just north of downtown San Antonio, Texas.

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Thanks for posting some video of the important end of the hammer. (As opposed to the fun end. ;) )

My one quibble: it looks to me like the turnbuckle adjusts the height of the dies and the many holes on the crank adjust the stroke length. (That's a nice idea, the holes. Is that your innovation of part of the Rusty design?) I'm only bringing it up to try to avoid confusion if the conversation turns to how to tune these hammers.

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Fcion - Thanks to your clarification on the adjustment holes, I was able to realize part of why my hammer wasn't hitting as hard as it needed to: it was short-stroking. I moved the pin to the furthermost hole (after having to do some cutting and welding to deal with clearance issues) and now it hits a lot harder. Thanks!


I've had to do some tweaking now that it's actually wired and able to move. I extended my contact wheel so that it actually covers the whole length of the tire, I had to shave a bit off the eccentric/flywheel to clear the motor housing when going full tilt, and most importantly, I moved the pivot bolt for the eccentric to its furthest-out hole, which lengthened the stroke. It hits a lot harder now. I still think I can get more power out of the machine. I have three leaf springs stacked. I think they are keeping the helve from whipping appropriately. I'm going to study the situation some more and then probably remove one or both of the secondary springs. And then I'll move on to changing my die holding setup and maybe brace the anvil a bit more.

Ah, the joys of using home-brewed machinery!

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Cool! Happy to help.

On Little Giant the spec is for the dies to be about one inch apart for working down to a point. So you may not need too much whip. (all that weight flying around scares me.) I know there are some other folks around who've built these hammers. Maybe one will weigh in soon with some informed advice ;)

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Arftist - I'll try to get approximate measurements today. As for the blows per minute, not sure, but you can see how fast it was hitting in the first video.

So I've increased the new hammer's power of its blows by increasing the length of the stroke, but my springs are now preventing me from getting as much power as it could. There are three fairly heavy truck (not pickup) springs in the helve, all about the same length, shackled together at the ends. Thinking about it, not a great way to get the spring to whip. I've actually had to crank the dies down to where there's no daylight between the die and the steel being worked in order to get it to hit, which I know isn't a good thing. So I need to alter my springs.

Here's what I'm thinking: If I shorten the top spring to about 1/3 the length of the main leaf (in the center) and arch the end a bit to reduce stress per the suggestion of another smith who made a nice one of these, can I leave the bottom spring long on the ram end of the pivot as long as it's not shackled to the main leaf? Seems to me like that wouldn't affect the hit, but could help support the main leaf as the ram is being lifted. Make sense?

For that matter, what about leaving the top leaf long on then back side of the pivot to help brace the main leaf on the down-stroke? Seems to me that it would preserve the whip on the fore-end and reduce it on the hind end, maybe delivering more force in the blow. Is that a good thing? Am I thinking about this right?

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  • 2 weeks later...

Update - I got my springs sorted out. I took off the top and bottom helper springs, which were about as long as the main spring and shackled to it at the ends, and replaced them with some of the medium-short leaves out of the stack, which still had their arch. These were approximately 1/3 the length of the main leaf.

What a difference! We had essentially converted the springs into a solid beam. With the main leaf free to flex and do its thing, the hammer hits nice and hard. It contacts the helper springs right at about the extreme of its flex, not putting undue stress on the main leaf (I believe). Turns 1" square into very thin flat with alacrity and ease. In fact, I may move the pivot point of the eccentric back down a notch or two to shorten the stroke and take the power down a bit for general forging. I'll have to play with it more and see.

I'm working on changing from bolted-on dies to a quick-change system. After I'm done with that, I'll shoot a new video documenting the changes and showing how hard the hammer hits.

I do have to say, I think that this is probably about as much weight on which a person would want to use a tire clutch setup (it has an 80 pound ram, plus the weight of the die, coming in over 100 pounds). It's eating rubber a bit. I'm thinking about putting a layer of sacrificial rubber, perhaps inner tube or round hay baler belt, around the tire.

Would a slack belt clutch with a flat belt be the next step up on a machine like this?

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Thanks, Sweany! The base is 1.5" thick, 18" wide, and 6' long, and it's anchored into the cement with four good-sized bolts. When we test-ran it sitting up on wooden blocks, it didn't threaten to tip over or anything. :)

Arftist - Finally measured those springs. They are 3" wide and .5" thick.

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  • 3 weeks later...

Having gotten my die holding system worked out (and seems to be working great so far!) and finally getting down to some real hammer time, I found that I have a few more issues to tweak, which I will try to get done before the New Year.

1. Add a greasing system to the ram guide. A couple of zerks, some channels milled in the plastic, and I'm good on that.

2. Re-stiffen the springs somewhat. I've discovered that the spring is now *too* whippy. It forms an S shape under power, and when going full tilt, the eccentric is rotating faster than the S can unwind itself and whip the ram down. This means that when trying to hit hardest and fastest, the ram often isn't hitting at all and you have to ride the clutch, which wears the tire. I'll put the original helper springs back on after I shorten them.

3. The wheel keeps falling off! It's held to the shaft with a key and a set screw. I need to put some Loktite on the setscrew and that should solve the problem.

4. I'll ascertain this for sure once I start playing with hand-held tooling a bit, but I'm thinking I may want to shorten my linkage up a bit.

The adventure continues! Thank goodness I've been able to understand what is going wrong at every point and been able to fix it. One of the big reasons I went with this design: simplicity! This is only the third level of complexity in a power hammer.

'Course, if I had a big air compressor, an air hammer probably would have been better. Some day, when I'm making more money!

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