Manual Screw Press?

[kraythe]

I was drooling over a fly press and I got to thinking about the mechanism and the power that the press generates. As I understand it a fly press generates most of its force via inertia rather than mechanical advantage of the press. As I researched this a bit more I found a site by a guy named Ron Reil on the fly press. On the bottom of that page he has a press that he picked up but is based off of mechanical advantage rather than inertia. He said it can generate over 100 tons of force which I thought was incredible at first. Then I got to thinking that with the right combination of basic machines (levers, screws, etc) why not? The only problem, I would think, would be to make it easy enough to use without the hands and also to make sure the materials wont fail under load. A load of 100 tons is a lot to put on a screw I think.

So that got me to thinking. I would love to have a fly press but alas I am monetarily challenged so spending a grand or more on one is out of reach for me. But I was wondering if it would be possible to fabricate a press in an H frame style (which should be easier than C frame I think, that would allow me to generate say 20 or 30 tons of force with a simple pedal. I can imagine using some four bar linkages for driving the press and some other basic machines. What i wouldn't know is where you could get the materials such as the screw that could handle that much force without stripping.

Does anyone know someone who has tried to do this? Are there plans out there i should be looking at or books? Is there any reason people can think of that it wouldn't be possible.

BTW. I did think of using one of the common plans to build a hydraulic forging press but discarded the idea for a couple reasons. First of all I have enough problems with my neighbors complaining about me hammering that if I was running power machinery all the time, I would get run out of town; so I need it to be quiet. Second of all, I like staying with basi, human powered, simple machines and so on rather than power equipment.

All reflections on this topic will be appreciated.

[eric sprado]

I have pictures on an old post in "Presses" of my almost century old combination
screw/arbor press. It does press things and I am making some tooling for it BUT,being SLOW, it doesn't replace a fly press. I can send you better pictures if you'd like. Eric Sprado

[ianinsa]

Hi,I do'nt mean to be a kill-joy, but I have an old H frame press(home made) that we picked up at an auction some years ago! Somebody spent a lot of time and effort to make that one. They wasted their time, it just does not compare our fly presses even with similar threads etc.
We now just use it as a glue press. Please rather save for the right thing rather that 'waste' it on something that might or might not work. Incidentally when we bought it we thought that it looked functional and well made, wich it is despite not living up to its looks.
Ian

[ThomasPowers]

*my* Hopkins #2 press cost $50 + 15% buyer's reaming and $35 for a rigger to load it into my pickup. I doubt you could buy the materials at a scrapyard to beat that price.

Screwpresses are often fairly inexpensive on the used market if you look hard enough as they are generally not used in industry today. You may want to start cultivating used machinery dealers---especially ones that have large old buildings crammed with junk...

You are correct in that everything needs to be engineered for the forces involved and so if you are cobbling something together you are "playing" with those forces and failure modes can be unpleasant if not downright tragic.

If you think about it the non-flywheel "lever" presses are just a vise set up a bit differently. What Ron was talking about was what I would call a bearing press---now generally hydraulic where slow force is wanted for controlled pressing of interference joints. You can find new ones cheap (eg: HF) and remove the hydraulic and try to retrofit a screw if you want but why not go with a hand operated hydraulic system?

[kraythe]

Thomas: that may be true out east but I have spent extensive time in Colorado trying to locate such items on auctions and whatnot with no luck whatsoever. By the time I journey from Colorado to the east, buy one on auction and ship it back, I might as wellbuy new. That is my problem currently. Out here, they just aren't around.

[ThomasPowers]

Mine was in Columbus OH; not quite "east" but close; I got to talk with a fellow who remembered when they bought my screwpress for the tool room back in the 1950's, he attended the auction where the plant had been moved to Canada and they were cleaning out the building.

The other one I know about came from Detroit MI; originally used the the Packard Plant.

I know of a bunch in NW AR; but don't think they are for sale. I can check though.

[lbas]

Mine was in Columbus OH; not quite "east" but close; I got to talk with a fellow who remembered when they bought my screwpress for the tool room back in the 1950's, he attended the auction where the plant had been moved to Canada and they were cleaning out the building.

The other one I know about came from Detroit MI; originally used the the Packard Plant.

I know of a bunch in NW AR; but don't think they are for sale. I can check though.

Just for curiosity, what's a bunch of screw presses doing in NW Arkansas?

And oh, I wouldn't be afraid to try to build one, start with a smallish one and be ready for it to do unexpected things. I got a 1 1/4" dia 2-start screw cheap (getting the nut made was more expensive) that I'll bolt into an H-frame from channel to give it a try myself. Expect about a ton from it like my little green press I put up on the forum a while back (which turns out to be something called an "Engraving Proofing Press"). Wheel? Don't know yet. Whatever I have, just trying to establish rough parameters.

Of course when you try stuff you have to take responsibility for what happens or doesn't, can't be silly and think someone else is liable (me or other). It's a real shame to have to say that, isn't it?

lbas

[fciron]

I found a couple of fly presses for a very reasonable price here in Louisville, KY. Also not the East.

Looking at the original post there is a slight misunderstanding: a fly press uses momentum AND mechanical advantage. A press that works through a screw only will not have the momentum. One could imagine that the swing of the flywheel (or weight) is analogous to swinging a hammer and that the screw gives that hammer a mechanical advantage. I swing the 80 pounds of fly wheel through 18 inches of arc and the ram moves a small fraction of that. The energy put into the work (by stopping the ram) is equal to the momentum of the fly-wheel multiplied by the mechanical advantage of the screw. Fly presses have multiple start screws with a steep lead because the momentum is as valuable as the mechanical advantage. They transfer kinetic energy from the fly-wheel into the work.

I had a screw action H-frame press in the shop, it would generate quite a bit of force, but it was very slow and not particularly useful for hot work. The ram was lowered slowly onto the die and it pushed rather than hit. It had a much finer thread than the fly press to get the maximum mechanical advantage. I believe it was being used to bend flat bar into pipe hangers before I got it, they're good for bending and cold forming, but not so much for forging operations which change the cross section of a bar.

I'm not trying to discourage anyone from building anything, just trying to explain the differences.

[kraythe]

Well Kentucky is still a 20 hour drive from Colorado. And to go there on the hope to get something is silly at best. Heck the gas alone to go there and back would be 400 bucks and the time needed would be hell. That is the point. Back east (and kentucky is east) you have it good. Remember that even kentucky is MUCH closer to the east cost then to colorado. I keep thinking I will have to buy one but the problem with that is cost.

And yeah I am aware of the difference in the two kinds of presses. The actual mechanism of the fly press is pretty simple, its the cast steel frame and screw itself that are tough to manage. If I built it I would build it oversized for safety so that you would bend the screw before the frame. The problem is I am not even able to find anything like CAD drawings or plans on the internet. One idea would be to use railroad rails for the heavy steel parts and high quality bolts that are tested to twice the force the press can deliver. Of course you have to calculate the force of the press and so on.

I am thinking the construction would be simple if you had the parts. For a C Frame you need a large wheel well balanced. If you cant find one from a scrap yard you can probably fashion one from steel stock. Railroad rails can take the stress of the frame for sure and if you used construction techniques such as that used for old style steel framed buildings it could work The weak point would be the actual joints where the uprights and top beam meet. The frame should also be under considerable tortion from the impact of the hammer. Its an interesting thought experiment.

As I think about it more though I wonder if something like a treadle hammer with a screw head mechanical advantage would be more useful. It would be controllable with the foot (something fly presses cant do) which would allow you to keep both hands on the stock. You could have the lever power something like a flywheel with an oblique gear and then have that fly wheel power the screw which would then impact the work. The force would be multiplied by gearing ratios and lever arm lengths. That could be something interesting to design. Again the trick would be making the frame strong enough.

Anyway, just thinking out loud. Its not like I am going shopping for parts or anything.

[fciron]

I don't think anyone was suggesting that you drive to either Kentucky or Ohio. If there was a jewelry shop in Jeffersonville, Indiana (10 minutes away) that had a couple of fly presses in the back, then there is a possibility of finding one in Colorado.

If I were fabricating a press I would probably use a box or tube section rather than an I-beam type section. I think old equipment had I shaped frames because they were most practical to cast. You could fab up a wicked strong box frame out of plate. (The modern Iron Kiss hammer has a box frame, old hammers have cast I frames.) Might be easier to find material.

You don't need a big wheel, you could build a barbell type fly-weight. Nor does it need to be that well balanced, it won't be spinning that fast. However, if you could find a fly-wheel off an old punch press that would be pretty awesome.

[ThomasPowers]

Well there was a small private mint in Eureka Springs AR, (now closed I wonder what they did with their tools...) And I have a friend who mints stuff and now is making buttons!

Mine came from a factory's "tool room" where it was used to straighten shafts and press bearings. Might find one in that type of thing even in CO!.

[MattBower]

I recently discovered that for the past few years I've been driving right past a couple of very nice power hammers at least a couple times a week. Not that they're for sale, but my point is that you never really know what people have tucked away in garages and back rooms. Don't give up.

[Neaves]

Here's a pic of my screw press. It has 2 speeds, the top wheel is the (relatively) high speed to bet the press to the desired point of travel while the side wheel drives the worm gear that gives it its low speed. You can't even see it move turning the low speed wheel but someone kindly added a motor to operate the low speed wheel which moves it along fast enough. I haven't had a chance to try forging with it... It's in storage until sometime this winter but it will bend a 90 degree angle in .75 inch plate effortlessly with a V die and crush bowling balls. I saw another one like this on ebay recently with a buyout of 750. I got this one off craigslist for 300 in Rhode Island. I believe it is whats called a die tryout press for injection molding dies. The two piece injection die was put in the press and pressurized to make sure the two sides where mated correctly. I could very well be wrong.

[yesteryearforge]

I have one almost identical to that ( maybe a tad larger )
was given to me free
It is an awesome press

Mike Tanner

[BIGGUNDOCTOR]

Look on the West Coast. CA has tons of manufacturing as does the Phoenix area of AZ. I believe there is a publication called the Machinery Supermarket that I used to get when I had my shop. It was put out by all of the big used machinery dealers in the West. I remember one being in Utah. Check craigslist, some pretty cool stuff shows up from time to time.

[DonS]

Something to consider if you are planning to build a fly press or buy a screw press for blacksmithing purposes:
If you use a single start lead screw, it will work much like a vise, and clamp down hard on the work piece.
Then you have to let go of the work piece and use both hands to back off the wheel if you want to take a second or
third run at it. By that time, the dies have sucked all the heat out of your project.

I built a small fly press using a 1-1/4 inch two start screw. The two start screw is less prone to jamming up.
(I originally picked up that screw to fix a leg vise, then realized that it would not hold things firmly.)

It's too bad someone does not sell a "kit" consisting of a 2 inch four start screw and matching nut to build a flypress.
Building the frame and ram only requires some heavy wall rectangular tubing and a decent buzz box welder.
See Hammer's Blow, Vol. 13, #3 (summer 2005). Shipping a screw and a nut would be a lot cheaper than trying to ship
a 600 lb machine to western Canada. If the kit was in the $100-$200 I would consider it.
-Don