#1
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shrinker and stretcher in the Pullmax
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.
shrnkstrchr1.jpg Until I found these on E-bay. Someone had welded a stem on one set and started to make a holder for the other. copper backing plate 026.jpg I ground off the stem and remachined the holder to bolt on the dies. copper backing plate 028.jpg I encaged an allen bolt in the stem to hold the dies copper backing plate 030.jpg copper backing plate 032.jpg copper backing plate 033.jpg 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 copper backing plate 035.jpg this is the second pass copper backing plate 039.jpg this is the forth pass copper backing plate 047.jpg copper backing plate 052.jpg copper backing plate 050.jpg 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
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Rick Scott The second mouse gets the cheese! |
#2
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Thanks Rick
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?
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John Ron Covell, Autofuturist books (Tim Barton/Bill Longyard) and Kent White metalshaping DVD's available, shipped from the US. Contact lane@mountainhouseestate.com for price and availability. |
#3
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Quote:
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Dan Pate |
#4
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Overhit
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.
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John Ron Covell, Autofuturist books (Tim Barton/Bill Longyard) and Kent White metalshaping DVD's available, shipped from the US. Contact lane@mountainhouseestate.com for price and availability. |
#5
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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
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Dan Pate |
#6
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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?
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#7
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Here's a 1957 Eckold patent document that shows the construction details.
http://www.eurospares.com/graphics/m...131_ECKOLD.pdf cheers, Michael |
#8
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Pullmax vs Eckold
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?
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John Ron Covell, Autofuturist books (Tim Barton/Bill Longyard) and Kent White metalshaping DVD's available, shipped from the US. Contact lane@mountainhouseestate.com for price and availability. |
#9
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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.
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Kerry Pinkerton |
#10
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Shrinker
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
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Adam. Assumption is the Mother of all Sutff ups. Resto Rod Race. |
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