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I Forge Iron

A novel approach to getting the necessary flexibility in your power hammer linkage.


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We don't need no STEENKEEN SPRINGS! Pretty slick, I love ingenuity in action. We used to put a tire between in the tow chain and tow vehicle to cushion the tow. Tires are excellent shock absorbers.

Frosty The Lucky.

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I’ve got a forklift tire on the back of my treadle hammer to absorb the force of the arm stopping at the top of its upstroke. Works really well. 

In thinking about the video, I realized that there’s really not much difference in principle between the tire and the rubber straps on a Bradley. 

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For the first iteration of my DIY power hammer I used tow straps instead of a linkage. I wanted to minimize the number of metal on metal wear surfaces. It worked ok, but with the design I used it required fairly frequent adjusting/tightening to keep everything lined up properly.

This makes me wonder if I could use a tire instead of the entire linkage/spring assembly.  Unfortunately the tension on the linkage arms does affect how well the hammer runs, and I'm not sure there's a reasonably good way to change the tension on a used tire.

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Adjusting throw and blow weight is a matter of adjusting the spring tension, not mounting brackets. Unless the hammer in question was built very differently than any I've ever seen and I have The Powerhammer book and a number of saved files of old power hammer patent drawings from when I thought I'd have to build my own.

I'll try this analogy, maybe it'll draw a useful picture. The adjustment to the arm mount on the crank pin. Is like getting the timing chain and timing sprokets set properly. You time the motor with a light and mark on the flywheel just like you adjust the hammer by adjusting spring tension on the link arms.

I can't see enough of the tire spring hammer but I don't see anything to suggest adjustability, crank or hammer arm.

Frosty The Lucky.

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I'm a fan of cranks too, besides my friends here. I was drinking coffee and sketching on my pad of graph paper in the old Country Kitchen restaurant when a friend, Cruz, walks by glances at the sketches of a drive mechanism for a power hammer I was working on and said, "Scotch yoke" and walks back to the conference table the coffee club hung out at. 

I sat there blinking and thinking for a minute then got up and headed back to ask what the heck he'd said and what it meant. Took good old Cruz maybe 90 seconds to describe what and how a scotch yoke works. I was danged close to reinventing a crank mechanism but was compensating for motions a scotch yoke damps naturally. 

Then before I got more than materials collecting started I got a deal on a 50lb. Little Giant and never built my design. Were I up to it I MIGHT have tried converting the linkages on my LG to a scotch yoke drive and reveled in a LG that didn't want to go walk about in use.

Frosty The Lucky.

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  Some designs of metal shapers run on Scotch yokes.  I've thought about using them to make sculptures wave at people.  Until I found 1800 mechanical movements book and forgot about that idea and started in on a new one.... or two.  I'd reccomend it.

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