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I Forge Iron

Fly press lateral thinking


brian

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OK Folks,
Have located a couple of presses but the cost of freighting them from one side of Australia to the other is prohibitive.:(
If I could get a 4 start thread cut internal and external, would it be possible to make the frame from some heavy pieces of steel,I've got some old axles made of 3" solid square stock that have a 90 degree bend on each end which I'm sure have been bent not welded.
Would any of the learned gentlemen be able to calculate how thick the steel would need to be to withstand the force of the screw?
Alternative would be a two post frame which I guess would be simpler to make though not as convenient to work with.
Guess it all depends on the cost of the thread cutting?:confused:

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Jeeze and i thought my new (used) press just about killed me moving it yesterday evening =D That thing's a monster imagedude. I think my press is between the equivalent of a #2 and a #3 at least by dimensions. and looking at flypress.com and other places. I think i'm getting heavy enough tools i should invest in a hoist of some sort before i blow out my back (and my neighbor's too since it took 2 of us to move the press heh)

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I have thought about contacting a local tech school about having them turn a multiple lead screw for me.

I worked as an engineer in a large machine shop that turned multiple lead acme screws. It is not that difficult if you have the right tools...

Unforatunately I do not have access to that shop anymore.

Has anyone tried their local tech school?

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I dont think a fabricated frame would stand the force of the screw (unless massivly constructed), your heading for a world of frustration & cost trying to make one.

You may as well make a hydraulic press, or a treadle hammer, or a simple mechanical / pneumatic power hammer.

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it actually wouldnt be that hard to engineer a structure that can deal with the forces involved, its the moving it afterwards that is the pain :P

pretty easy (and relatively cheap) to build a steel structure that is then cast withing concrete. Steel is good for shear, concrete compression, pretensioned for tensile strength and the design for torque. When compared to casting iron it makes a lot of sense, but you better be pretty sure of where you want it located :p

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We would like to know where in the world your located.



and if Carmen Sandiego is with you :P

I think there are two scenarios here
1. having parts of a press made, which inst likely a great time or cost saver and gets the negative vote or
2. developing the skills and tooling to make a fly press, which can pay off with other projects ;)
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I had been looking for a small puch press at a junkyard when I was considering building a flypress. The Frame, bed and ram are all premade. Just replace the crank and flywheel with a screw assembly.

The Ram and bed plate may not be standard for flypress tooling but were made standardized easy tooling changes.

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Man, don't try to make a flypress. Find a way to buy one and spend your time making tools and jigs and actually squishing metal. You really do get a lotta tool for the $ and it will work right the 1'st time.


You may be right Nuge.
Much as I hate buying stuff,I like making it,:( but the cost of cutting a 4 start thread is more than buying a second hand press .Add to that the time spent making it plus the chance that it may not work and I may be better off buying one.
Then again...... might phone a few of my old mates and see if I can find an old lathe or some other machine that has a thread of the right type on it,must be something that uses similar lying around somewhere.

Just goes against the grain to buy stuff. ;)
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This may be a little left-field, but does the thread neccesarily need to be cut? Would a wrapped-and-brazed thread like on old vises work I wonder?


Would it be Possible, yes, practical not so sure. Remember that when you wrap the threads that you are making both the threads for the screw and the nut, so you are trying to control 8 treads in a helix pattern, with constant pitch and lead. then you remove one set of four and braze them into the nut while maintaining that pitch and lead. Then braze and lap.
I once did a multi start nut on a screw from a garage door opener, when I was making a fast closing vice. I took a piece of square pipe and centered a short piece of the 2 start thread in it after I covered the tread with carbon from acetylene. (carbon acts as a release and spacer) I sealed the bottom of the pipe to a piece of pine with play dough and pored it full of babbitt. I had to lap the nut with valve grinding compound. I am not sure that babbitt would hold up under the massive forces of the fly press, but the same process can be done with a brass nut. That might solve half of the problem.
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