shrinker and stretcher in the Pullmax

[HEATNBEAT]

I have been wanting to make a deep throat shrinker and stretcher ever sence I used Lazze's, when I took his class 6 years ago. But the dies have been out of my price range.

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Until I found these on E-bay. Someone had welded a stem on one set and started to make a holder for the other.

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I ground off the stem and remachined the holder to bolt on the dies.


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I encaged an allen bolt in the stem to hold the dies

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I bent 1-3/4 angle out of 16 gage
I marked it every inch but I feed the materail every 1/2"
this is the first pass

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this is the second pass

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this is the forth pass

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I didn't take to many pictures of the stretching but I did the same as the shrinking I stopped here anymore and I think the material will just rip.

NOTE:

I have a P9 and the distance between the collets when the upper is all the down is 4"( that is about 1/2" more then most pullmax) and I need every bit of it. But if you use your second slot on the deepth you might be able to have eough room.
I also have a VFD on my pullmax so I can slow it down(A MUST). I set the speed at 5 Hurtz about 60-100 strokes per minute. that was enough time for the dies to react. I moved the material in slowly it hit 4 times going in and the same going out.
I was very pleased with the results

[Overkill]

I've thought that should work. Just wonder how shrinking dies, on low speed, will work in smaller Pullmax machines?

Clay Cook used to use Eckold shrinking dies in his P2, but said it would flex the frame. I don't know what speed he was running. Truly, I believe that to allow the dies to react, that low speed, just like the Eckold uses, is the key.

Would love to hear the thoughts of those with Eckolds about the Eckold vs Pullmax with VFD debate. Why can't Pullmax, at low speeds, match the Eckold - assuming similar tooling?

[route56wingnut]

Originally Posted by Overkill

I've thought that should work. Just wonder how shrinking dies, on low speed, will work in smaller Pullmax machines?

Clay Cook used to use Eckold shrinking dies in his P2, but said it would flex the frame. I don't know what speed he was running. Truly, I believe that to allow the dies to react, that low speed, just like the Eckold uses, is the key.

Would love to hear the thoughts of those with Eckolds about the Eckold vs Pullmax with VFD debate. Why can't Pullmax, at low speeds, match the Eckold - assuming similar tooling?

The major difference between these machines is that Eckolds are designed with the ability to "over hit".That is that there are multiple contact points that are made of a non metalic material that wont ruin the machine(as I would suspect may happen over time) with a recip machine.As has been mentioned elsewhere the speed of the stroke is realy critical with this type of dye as it has to have time to recover.That is it has to go to its base position so as to fully hold the metal and then either S or S.The design of an Eckold die is completely different and to make these dies work correctly you would unfotunatly have to then Overhit with a machine not designed to do so.Dan

[Overkill]

Dan,

I was hoping you'd chime in. I'm not understanding what you mean by 'overhit'. The word is used when talking about power hammers, and I understand the meaning there. As the eckold is an electric reciprocating machine - I'm missing the point.

[route56wingnut]

Ill just refer to the way the Pmax and Eckold work as I have dug into both of them.First an overhit would be most similar to me a piston traveling a given distance in a bore with a pre determined stroke and you readjusted the stroke and now it just hits the head.Over time you get what will happen.Now the Eckold does not have a dirrect conection between the crank and (rod so to speak)It has a large flywheel that rides against a composite wheel so there is also little or no friction .Also in the front of the machine where the die holder goes up and down,it also has a rubber or composite to allow another contact point to have a little cussion.Dan

[mr.c]

Why couldn't you machine a deep pocket in one of the die holders(lower) and place a piece of rubber or urethane between the holder and the die? The sides of the pocket would need to be thick enough to keep the pressure from blowing out the side. Wouldn't that take a bit of the shock out of the mechanism of the Pullmax head?

[Michael Moore]

Here's a 1957 Eckold patent document that shows the construction details.

http://www.eurospares.com/graphics/m...131_ECKOLD.pdf

cheers,
Michael

[Overkill]

Dan,

Thanks for the explaination, and Mr. C, thanks for the idea.

Using Rick's P9 for discussion purposes, the machine has so much more capacity, do you think the toggle mechanism would be damaged when using as a shrinker over time? Because the machine is so overbuilt, I would think it could stand up to the stresses.

Mr. C's shock absorber idea (could use other materials) would reduce the shock loading on the toggle mechanism - would that work? I know that when you get the dishing doming dies too close, the machine will sure make noise.

Expanding on Mr. C's idea, I think I'm going to try to get a 5/8" square piece of urethane, cap it on both ends with sheet metal, drop it down inside the lower tool holder, leave the collet slightly loose, and attempt to see what that contained shock absorber will do. Thoughts?

[Kerry Pinkerton]

I believe if Rick ever bottoms his dies out, they will break into pieces. The P9 is MASSIVE compared to lesser machines like my P6. It has enough power (5hp?), inertia, and mass to run slow enough and have the oomph to compress the dies at low speed. And those dies require much less pressure than the Eckold or Marchant dies.

When I ran my Eckold dies in the P6, it would stall at slow speed and at high speed it was making expensive noises and flexing. Gave up on that experiment very quickly.

There is NOTHING in the Pmax (or most other recip machines) that has ANY give at all. The Eckolds is a different beast as there are places, as Dan described, where there is elastic material in the drive train. This, coupled with the flywheel, allows the machine to use the rotating mass of the flywheel at slower speed to compress the tooling. The Eckold machine is really a different thing from what we normally call a reciprocating machine.

[Resto Rod Race]

I have been wondering about this and been looking through some older posts, I have a P5 pullmax and have been looking at buying the eckold style shrinker dies, but from whats been said the rpm of the machine is to fast and it wont have enough ompf if i get a variable speed unit for it, and i might have clearance issues?
Thanks
Adam