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Author Topic: Educational size rotational molding machine  (Read 49776 times)

Dick Stohr

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Re: Educational size rotational molding machine
« Reply #105 on: January 13, 2015, 09:53:32 PM »

Awesome, just WOW!!!!!!!!!!!!!!!!!!
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cecil

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Re: Educational size rotational molding machine
« Reply #106 on: January 13, 2015, 11:07:22 PM »

I could see how you cleaned up all the equipment before you started the project, that you are a craftsman. I can't believe you took that big mess of plastic and created so many beautiful tops. The Tips and colors are excellent. When I cut a tip I use Mo max Cobalt with a lip. I turn the body then I cut the neck with the compound set at 45 deg. then out the door at 38 deg. My wood top I made took me about twenty hours. I'm old and slow. Also I put one hole in for the lead, my teacher taught me to use two holes, the Y balance. Now I will have three holes?
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Neff

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Re: Educational size rotational molding machine
« Reply #107 on: January 13, 2015, 11:41:25 PM »

Great googly moogly those look sweet!
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jim in paris

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Re: Educational size rotational molding machine
« Reply #108 on: January 13, 2015, 11:47:09 PM »

oh la la !! what an amazing display !beautiful work !
thanks very much John , and thank you again more for having let us follow the whole process step by step.


Big Up  ;--))


jim
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Eric

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Re: Educational size rotational molding machine
« Reply #109 on: January 14, 2015, 12:55:06 PM »

Amazing work (and pictures) John!!!
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JNeff

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Re: Educational size rotational molding machine
« Reply #110 on: January 14, 2015, 01:43:08 PM »

Terrific job John. We definitely put the molding machine in the right hands.
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johnm

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Re: Educational size rotational molding machine
« Reply #111 on: January 14, 2015, 07:58:49 PM »

Some general numbers for these tops with tips installed.
nominal overall height is about 6.3 inches (160 mm)
nominal maximum diameter is about 4.7 inches (120 mm)
average weight is about 313 grams (0.7 lbs) but extends over the range from 272 grams to 353 grams which is a variation due to how much material I packed into the mold.  The earlier tops are lighter.

I've finally cut one top in half to see the distribution of material inside.  The balance on this one was quite playable but there was a significant vibrations and a noticeable visual wobble.  I marked the "high" side of the wobble while spinning with a sharpie and made the cut across that spot to the opposite side.  One side is noticeably thicker than the other and a clear lack of symmetry is seen where the tip would be installed.  I suspect that for this example the collection of extra material all on one side is coincidence and that on others the distribution might be more randomly spread around.
The inside surface is fairly smooth but there are some small shallow voids (hard to see in the picture).  The material exposed in the cross section is well merged and should provide a durable top.



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Kirk

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Re: Educational size rotational molding machine
« Reply #112 on: January 14, 2015, 08:31:01 PM »

John,
They look superb.
By the way what size threads are you using for the tip?  We probably have some spare brass inserts that are designed for plastics floating about the office that I could send you.
Kirk
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the Earl of Whirl

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Re: Educational size rotational molding machine
« Reply #113 on: January 14, 2015, 10:14:37 PM »

Those pictures are wild.  It is like looking at an x-ray of tops!  Very fascinating.

I shared this thread with an adult in our youth program to show him why this forum means so much to me and others.  He sat there and looked at all the pictures with mouth wide open amazement.  We are a bunch of fortunate individuals who have found each other and to work with this genius!!!
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Kirk

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Re: Educational size rotational molding machine
« Reply #114 on: January 15, 2015, 12:31:05 AM »

I have just been informed that I will not be throwing one of these in the kitchen.  :)
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Shootist

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Re: Educational size rotational molding machine
« Reply #115 on: January 15, 2015, 12:43:32 AM »

I have been following this thread since it started. I enjoy reading the post and seeing the photos of John's amazing progress with making these Spintops.

John they are truly amazing to see.
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cecil

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Re: Educational size rotational molding machine
« Reply #116 on: January 15, 2015, 05:45:06 AM »

11 OZ is very light, I like 13 OZ. If you put a tip with a half inch neck it would be a fantastic wire walker. Maybe 110 feet. I cant Waite to see one in action. I'm so happy to see big tops in the picture now. Some of my tops have a aluminum lighting rod in them, so I can pull them in with a 6-32 screw. To me it's allways easier to add weight than take it off. My son runs C.N.C lathes, and that's the way they check some of there parts. Cut them in half. I never thought I would see a big top cut in half.
« Last Edit: July 25, 2019, 09:23:21 PM by cecil »
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poptop

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Re: Educational size rotational molding machine
« Reply #117 on: January 21, 2015, 02:22:08 PM »

The middle "group photo" is hereby nominated for the 2015 photo contest...

Such a nice bunch of good looking tops!  :D
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Erratic Wobbler

ta0

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Re: Educational size rotational molding machine
« Reply #118 on: January 21, 2015, 03:11:31 PM »

The middle "group photo" is hereby nominated for the 2015 photo contest...

Such a nice bunch of good looking tops!  :D

Mm, I prefer the first "honeycomb" group photo for the contest.
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the Earl of Whirl

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Re: Educational size rotational molding machine
« Reply #119 on: January 22, 2015, 08:08:23 PM »

wow!  Wow!!  WOW!!!

I just spent three hours at the University of Cincinnati with the one, the only johnm.  My head is spinning with all I saw and heard.....and I have been there several times before!  Don has to be so happy with what he has done with the rotational molding machine.  I picked up lots of HDPE tips, lots of turning tips and lots of new items for the hall of fame.  What a day.  What a good friend!!!

Thanks for all your extra time and loving care with those tops.  I still cannot believe all the work and effort they took.  They look beautiful.  I cannot wait to throw mine.
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