juzwuz
has rocks in the head
Member since April 2010
Posts: 526
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Post by juzwuz on Oct 26, 2011 1:20:55 GMT -5
I decided to pick up a few parts for a sphere machine. Hopefully I can get something working within a month. I bought some "plans" from here: home.earthlink.net/~jmcdohsd/index.htmlI just e-mailed the guy and asked about the bead mill, 2 head and 3 head sphere machine plans. As he states, they aren't really blueprints but the plans give you the general idea. He also seems quite willing and helpful in answering questions. I decided to try and make things out of mostly aluminum rather than wood. I bought the GE gearmotors (105RPM) from here: www.surpluscenter.com/item.asp?item=5-1074&catname=electricPicked up a few hinges, wire, electrical switch, box from the hardware store. Also had a piece of aluminum t-slot extrusion for the base and a piece of 1/8th inch thick aluminum for the motor mount. I think I'll start with a 2-head machine and maybe make the design flexible enough to turn it into a 3-head machine if needed. So far, I've really only cut the aluminum plate in half for the motor mounts and tried to roughly position things. What is a good height for the motor installation above the base or does it matter?  |
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Post by jakesrocks on Oct 26, 2011 5:38:41 GMT -5
Don't think there's a set height for the motors, but I'd set them high enough to set a catch pan under the cutters, to catch most of the mud that will drip off.
Don't forget to have your motors slanted down slightly, so mud and grit will run away from the motor bearings.
Somewhere on here there was a discussion about only using one capacitor to start all of the motors. I think they discussed how to wire it up.
I like your idea of using the tee slot extrusion for the base rails. Should help to keep everything properly aligned.
Don
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Post by christopherl1234 on Oct 26, 2011 11:06:53 GMT -5
I am eager to see how this turns out!!
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juzwuz
has rocks in the head
Member since April 2010
Posts: 526
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Post by juzwuz on Nov 3, 2011 2:21:55 GMT -5
I wasn't quite sure what to do about the grinding cups. I would like to just use diamond rather than grit. I've seen people use diamond core drills so I decided to get some motor arbor adapters and some drill chucks which can hold up to 1/2" diameter drill bits. Unfortunately the adapters which are supposed to fit on a 1/2" shaft are just slightly small and I can't quite get them to fit very well on the motor. Not sure what to do about that yet but here is a picture of the test "fit". I guess I could try drilling them out or something else? Any ideas?  |
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quartz
Cave Dweller 
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,359
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Post by quartz on Nov 3, 2011 20:58:27 GMT -5
My inclination would be to contact the place of adapter purchase and ask them why the pieces don't fit. I have had some problems with parts in the past and the suppliers were very good about making them right.
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Post by jakesrocks on Nov 3, 2011 21:15:03 GMT -5
Before doing that, I'd put a micrometer on the gear head output shaft. Lots of these parts are coming out of China, and may be a metric size slightly larger hand 1/2".
Another thing you could try is to wrap some sandpaper around a dowel and twist it inside your adapter a few times. There may be burrs inside from the machining process. Also, back the set screws out all the way before trying to fit your adapter to the shaft. The set screws should line up with the small flat area on your output shaft. I notice from your picture that the set screws are almost 1/4 turn off the flat.
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rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
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Post by rockhound97058 on Nov 3, 2011 23:28:42 GMT -5
If I get a chance this weekend - I'll snap a photo of my sphere machine. It's a design a relative of mine used to build and sell years ago. I have thought about building some more myself and even try to sell one or two.
I'll take pictures of my motor shafts and show you what my relative did... They sleeved the shafts with 3/4" round stock with a set screw and the end of the shaft is threaded with pipe thread to be able and use the bell reducers.
My machine uses all three capacitors and has a metal box built with a lid to house them and keep sticky fingers from touching them lol.
Anyrate - I'll try my best to get some photo's this weekend!
Jason
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juzwuz
has rocks in the head
Member since April 2010
Posts: 526
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Post by juzwuz on Nov 4, 2011 14:29:57 GMT -5
I used my cheap digital calipers (made in China of course) to measure the motor shafts and the adapters. The shafts are 0.500 inches and the adapters are around 0.497 to 0.5 inches. The finish inside the adapters seem kind of "rough" so I will try the sandpaper trick.
I do have some 5/8-11 adapters hopefully coming soon. I have some stone polishing pads from 200 grit up to I think 1500 grit that should fit on these adapters. I also ordered some diamond core drill bits with the 5/8-11 threads. I have one 2" diameter bit that I will use for "coring" and two 1 3/8" bits for the sphere grinding. Hopefully these sizes will work for a 2" sphere.
Just for fun, I'm setting up my small CNC mill to drill the holes for the motor mount plate. I haven't cut metal on the mill before except for engraving on brass so it should be "interesting".
Jason - I'd appreciate any pictures you might have of your setup. I'm really taking the "MacGyver" approach to making this machine so pictures of working machines will help a lot. Eventually, I'm hoping to make some spheres from the obsidian I got from you a while back.
Justin
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NDK
Cave Dweller
Member since January 2009
Posts: 9,440
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Post by NDK on Nov 4, 2011 20:29:59 GMT -5
Keep the pix coming, Justin. I love seeing projects like this come together!
Nate
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Post by jakesrocks on Nov 7, 2011 8:09:19 GMT -5
Your machine will shake a bit in the rough grinding stage, until the spheres are trued up. After you have a true sphere things will tame down. The more time you spend on the grinder taking sharp corners off of your sphere blank, the less time you'll get that shake.
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juzwuz
has rocks in the head
Member since April 2010
Posts: 526
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Post by juzwuz on Nov 16, 2011 15:54:06 GMT -5
I received some 1/2" to 5/8-11 motor shaft adapters from HP Lapidary and they are quite nice. I might abandon my plans of using the drill bit chucks and just go with the diamond core drill bits with the 5/8-11 thread.
I ordered some 4-pin molex connectors for the motor wiring and hopefully it will get here by the weekend. I think I have some time this weekend to make the 3rd motor plate. Right now, I think I can make the machine work as a 2-head machine and also be able to easily convert it to a 3-head machine and back again on the fly.
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Post by jakesrocks on Nov 16, 2011 16:07:49 GMT -5
Justin, do you have a link for HP Lapidary ? I want to find out if they have adapters for 1/2" - 20 to 3/4" NPT. I want to build an old school single cutter sphere machine, using an old flat lap arbor that I have. I've seen spheres up to bowling ball size made this way, and want to do a pictorial to show our members that it can be done.
Don
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juzwuz
has rocks in the head
Member since April 2010
Posts: 526
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Post by juzwuz on Nov 17, 2011 0:06:51 GMT -5
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juzwuz
has rocks in the head
Member since April 2010
Posts: 526
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Post by juzwuz on Nov 17, 2011 0:07:38 GMT -5
Justin, do you have a link for HP Lapidary ? I want to find out if they have adapters for 1/2" - 20 to 3/4" NPT. I want to build an old school single cutter sphere machine, using an old flat lap arbor that I have. I've seen spheres up to bowling ball size made this way, and want to do a pictorial to show our members that it can be done. Don Don, That would be a cool tutorial. Looking forward to it. Justin |
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Post by jakesrocks on Nov 17, 2011 10:14:50 GMT -5
Justin, I found HP Lapidary. They don't have the adapter I need. McMaster doesn't have then either. I'll probably need to have one made special. If anyone on the board has the equipment to make an adapter, I'd like to hear from them.
The adapter would have to be made out of 1" hex stock with about 1" of 3/4" NPT on one end, and center drilled on the other end with 1/2" 20 female thread about 1-1/2" deep. It would have to be tapped with a bottoming tap so the threads go all the way to the bottom of the hole. The whole adapter would be about 2" long, with the hex sides left on the unthreaded portion, so I can use a wrench to remove it. My cutter cups would be standard bell reducers, with 1 reducer for each grit size to eliminate cross contamination.
Don
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juzwuz
has rocks in the head
Member since April 2010
Posts: 526
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Post by juzwuz on Nov 19, 2011 16:36:03 GMT -5
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Post by jakesrocks on Nov 19, 2011 22:25:16 GMT -5
I'm just getting ready to order 3 of those motors from the surplus center. Gonna build a 3 head machine loosely based on your design. Once I get started, I'll post pics.
I'd go with at least 16 gauge wire for your motors. 14 gauge would be even better.
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juzwuz
has rocks in the head
Member since April 2010
Posts: 526
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Post by juzwuz on Nov 19, 2011 23:08:24 GMT -5
I'm just getting ready to order 3 of those motors from the surplus center. Gonna build a 3 head machine loosely based on your design. Once I get started, I'll post pics. I'd go with at least 16 gauge wire for your motors. 14 gauge would be even better. That would be great! I really like the T-slot aluminum extrusion for the base because it is so adjustable and fairly easy to work with. Hopefully I'll have some pictures of the transformation between a 2-head machine and a 3-head machine. I found it slightly cheaper to order the motors directly through surplus center rather than their ebay store. I went to the hardware store and bought 25 ft of 4 wire, 14 gauge, 600V indoor copper wire which was actually cheaper than the low voltage wire. I'm just working on the switch and motor wiring and hopefully cutting another motor adapter plate. |
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