WarrenA
fully equipped rock polisher
Member since November 2003
Posts: 1,530
|
Post by WarrenA on Dec 12, 2010 18:00:36 GMT -5
Has anyone here made their own sphere making machine? I have the motors (3 matching rpm) but have never seen one of these machines so I have no clue on where to start. Any pitfalls to avoid etc. or where to find some sort of a plan. Thanks Warren
|
|
|
Post by jakesrocks on Dec 12, 2010 18:22:20 GMT -5
I have a buddy in Rapid City, S.D. that built one. I'll see if I can find his pics, and post them here.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Dec 12, 2010 18:34:29 GMT -5
|
|
|
Post by jakesrocks on Dec 12, 2010 19:20:00 GMT -5
The sphere machines from Gemworld are a much better design than the one from Sphereheaven. Note that the sphere cups and shafts face downwards. If they face upwards, grit and water has a tendency to run back towards the bearings and motors. Even with sealed bearings, over time grit will work its way inside, shortening the life of bearings.
|
|
|
Post by tortuga on Dec 13, 2010 19:21:58 GMT -5
I have my eye on one right now from an older gentleman who is retiring from the business. The machine was made by a local lapidary shop owner of his own design. A sphere made by one of this design was measured by a nearby university (Purdue) as being within 1/1000 of an inch of a perfect sphere. He's going to sell it when he's done with his last batch of spheres (wrapping it up near the end of December by last estimate). If I'm able to get ahold of this, I'll take measurements and post pictures for everyone. The shop owner passed away this year after selling the shop about 6 years ago. No more are being made, so I don't see any harm in sharing the design.
|
|
Rockygibraltar
fully equipped rock polisher
Member since February 2006
Posts: 1,404
|
Post by Rockygibraltar on Dec 13, 2010 21:36:26 GMT -5
One of my favorite books, The Art Of The Lapidary", has a piece in it about sphere making. The author's sphere machine only uses one rotating cup. The other is held in the hand. His machine and method is very simple and effective. If I ever get around to doing spheres I want to try it.
|
|
chromenut
fully equipped rock polisher
Member since December 2009
Posts: 1,971
|
Post by chromenut on Dec 13, 2010 22:08:56 GMT -5
Question to you sphere gents, on the rough stones prior to grinding, how close to sphere shape do I need to make them so they'll work in these kind of machines? I have a lot of 2 to 3" preforms that are like I don't know, maybe 34 sided or something like that. So obviously I need to cut down the sharp edges but how much more do I need to shape them?? Here's one of my preforms:
|
|
|
Post by jakesrocks on Dec 13, 2010 22:22:34 GMT -5
One of my favorite books, The Art Of The Lapidary", has a piece in it about sphere making. The author's sphere machine only uses one rotating cup. The other is held in the hand. His machine and method is very simple and effective. If I ever get around to doing spheres I want to try it. I had an old friend that used to make them like that. I've seen spheres up to bowling ball size that he did. He used an old rotating flat lap with pipe fittings screwed on the shaft, and ran it at the slowest speed. He only used the one cup, and leather gloves on his hands. He rotated the ball in his hands to get all of the sharp edges ground off. He had different gloves and pipe fittings for each grit stage. To polish them, he used the hand held pipe fitting, and had leather stretched across the fittings.
|
|
|
Post by lonetreestudios on Dec 13, 2010 22:47:39 GMT -5
My $0.02 worth, I have a whole folder of info somewhere (will see if I can find it to post) and 9 or 10 machines I hope to have back up running sometime soon..
- 3 head machines (or even 4) are faster, but 2 head machine forms the more perfect sphere. - The closer the preform to spherical the better, but it doesn't have to be perfect. The "rougher" the preform, the more in-line you have to keep the cutter cups to keep the 'form from popping out. While this would sound ideal, perfectly in line cutters give you an oval, not a sphere. - There is a guy in Florida that regularly sells his 3 heads on eBay, you can get a pretty good idea from him. - Rule of thumb is that the cutter cups are 2/3 the diameter of the desired finished sphere - You didn't mention your RPM, but most of the machines I have seen are between 75 and 150 (I think), mine are all 105 I believe, old gearmotors from copier machines. - Cutter cups are easy to make from cast iron reducer fittings, etc. I recommend staying away from galvanized fittings, as they can mark-up a light or dark stone as the zinc wears off, may not be a concern to you based on material. Cast also rusts quickly and easily, something to watch for when starting up after a break - I will try to get some pics of my machines, grit dispensers, etc, and post them
Best of luck!
Rodney
|
|
Steve
has rocks in the head
Member since June 2005
Posts: 506
|
Post by Steve on Dec 14, 2010 23:30:39 GMT -5
The design of this sphere machine is closer to the homemade machines I've seen. www.sphereproducts.com/spheremachine.htmFor these swing arm types you can either use springs at the top to pull the arms in (which is how the one above works), or put a strong spring underneath to push the arm forward (the 3 head Covington design). I have 2 homemade machines that I got used and rebuilt. They both use the spring underneath method. If you go with grit instead of diamond you will have to invent a grit dispenser. It seems that every homemade sphere machine uses a different Rube Goldberg setup to dispense grit. If you know someone who reloads bullets go look at how they dispense gunpowder. It will give you plenty of ideas on how to dribble grit.
|
|
|
Post by jakesrocks on Dec 14, 2010 23:41:05 GMT -5
Does anyone have any experience with the sphere preformer from gemworld ? Looks like it would make cutting preforms a snap.
|
|
WarrenA
fully equipped rock polisher
Member since November 2003
Posts: 1,530
|
Post by WarrenA on Dec 15, 2010 21:16:42 GMT -5
Thanks to all who have responded. I have looked at lots of designs and have concluded that I need to just jump in and make the thing. I will post pictures when I get it finished. this is going to be fun!!!
|
|