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I Forge Iron

Interested in building a fly press


Zylogue

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Daniel: I was about to suggest some reading of a previous post, but it looks like it's gone from when the server died. Dang. Several of us posted information on flypress construction.

The upshot of it was that making a flypress is VERY difficult for the average home shop. A fly press is not just an acme threaded rod in a nut inside a 'C' clamp looking thing. It is a fairly radical thread tooth, with several leads... at least three, though new presses are more typically four now. So you have to machine a multi-lead squarish thread, and then make a substantial nut in a fairly massive frame somehow to withstand the pressures generated by the throw of the press.

A simple single-lead acme threaded rod will not work. All you will succeed in doing is making a vertical vise. When the tool bottoms out it will bind, just as a vise is supposed to do because the thread TPI is too high. More specifically, the throw is not radical enough to let the screw rebound at the bottom.

If you can get an aggressive 3 or 4 lead acme rod, and can make the frame, you CAN cast the nut. The nut in mine, for instance, is made of high-strength tin babbitt and has held up quite well from my last rebuild.

Having said all that... I'm still trying to figure out how the flypress is part of civil war reenactments. I wasn't aware they were even used outside of machine shops during that time.

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  • 2 weeks later...

Chris: Thanks; that did it.

I would like to hear a follow-up evaluation sometime. My suspicion is that they were able to develop significant pressure, but not real speed and I would be surprised if it didn't bind at the bottom. I've never seen a real single-lead flypress. Screw-press yes; but not 'fly' press.

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Chris: Thanks; that did it.

I would like to hear a follow-up evaluation sometime. My suspicion is that they were able to develop significant pressure, but not real speed and I would be surprised if it didn't bind at the bottom. I've never seen a real single-lead flypress. Screw-press yes; but not 'fly' press.



Thats what I figure too....but like I said above I'm not sure how it worked out.I'll keep an I out for more info.
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