continued...
WOOD DOWEL UPDATE
Use wooden candle cups from Hobby Lobby. These are made out of wood and the ones that I have are 7/8" X 1". They can be force screwed right onto the 1/4" flex-adaptor. There is a small hole in the center of the end and you will need to "dish" (where the marble goes) this out with a drill and bit. With the small hole as the guide the "cup" will be centered. They work perfect for me. Here is the item number at Hobby Lobby: 165894 Candle Cup Value pack; 22 pcs. 7/8" X 1". 22 pcs or cups cost all of $2.99. Easier than using the dowel rods mentioned below.
Well now, we have the marble ready for final polish. First we have to make the polishing heads and these must be made from wood. Caution-Never use oak. Oak has about three different oils in it and will leave a rather dull shine on the marble. I use dial rods of various sizes. I'll talk about the 3/8" size. First if you have a drill press, pick a bit that will just cover the end of the rod and "dish" or "cup" out the end. Do not leave shoulders on the dish or cup. The more surface of the wood that touches the marble the better. You can use two dowel rods of one size, and the other dowel rod can be a larger diameter to help hold larger marbles. This puts more wood surface on the marble.
After you have a nice dish or cup in the end saw it off 1 1/4" long. Now sand or whittle the sawed of end down to the point that you can screw it into a 1/4" coupling. The interior threads of the coupling will cut threads in the wood and hold it in the coupling. Do this for all three heads. I use dowel rod sizes all the way up to and including 3/4".
Now you are ready to final polish a marble. Here again, Patience, Patience, Patience. You may have to work with the machine to get it set properly. In a Solo clear cup put 2 heaping teaspoon of final polishing material. (White powder) Add water to a half inch above the powder and stir. It is now ready for use.
Make a new chain for this step and keep it separate from the others. I leave a marble in the final polish for at least one hour and sometimes up to 4 hours. You won't have to stir the compound nearly as much as you did the 220. By the way, you won't have to stir the 1000 grit much at all. When checking the progress of the marble, again I caution you to never put it in cold water. Sometimes if my hands are real cold (most of the time), I will warm them in the warm water before handling the marble. You will find that you will wash your hands more often in a day than a doctor does.
When setting the uprights for working on a marble, make sure that they are tilted in at the top 10 to 15 degrees. This will make it downhill from the coupler grinding head to the marble. This will cause the pickup chain to run on the marble side of the coupling and against the marble. Don't worry about this hurting the marble as glass is harder than metal and that's right where you want the chain to run. This tilting of the heads is also a must to help the turning in every direction of the marble in the heads.
A few words about the flex-adaptors. Due to the shaft hole being cut too small in the uprights on my machines the bottom edge of the upright shaft hole will finally cut the back of the compression nut off and then I have to replace it. I had you folks cut the holes bigger and I don't think you will have this problem. If you do, I have figured out what to do.
First, don't expect McMaster-Carr to sell you any parts separate for the flex-adaptor. You have to buy the whole thing (they won't even sell you the bubble washer). I didn't like that, so I did some leg work and found another way. Here it is. First go to an auto store and pick up some hose (UPC 038244768552 0488 OD 7/32"OD ID 5.6mm). Outside diameter is 7/16" and the inside diameter is 1/16" (about 30 cents a foot). This will work and you should have some on hand as the rubber will wear out in the adaptor. Use the old rubber washer to cut the length of a new one. If the hex compression nut gets ruined like they do sometimes with my machines, you will need to replace it. I finally found a hex nut that will work at True Value. It is as follows: Master Plumber-5/16 or 5MM compression hex nut (2 for $1.79). Number 287-631. Much, much cheaper than buying the entire Flex-adaptor.
What do you do to get the compounds out of the surfaced bubbles and etc? Buy yourself a "sonic" for about $38.00 or so. This is the same thing that a Jeweler uses to clean jewelry. It's an almost must if you are planning on reconditioning marble. Make sure you get a nice ultra-sonic cleaner. The cheap ones don't work. You want to make sure there is no white polish showing in any of the pits.
Let's talk about sizes of grinding and pre-polish heads. Using the 1/4" all thread nipples a person will soon have the threads coming loose and binding up the machine (when this happens, I use pliers to break them off and keep going). There is a way around this. I'll talk about the 1/4", but this can apply to bigger sizes also. Using a 1/4" by 2" nipple, saw them in half. This gives you an area of pipe with no threads. Dish out the non thread end with a drill and bit. Not much, but good enough that there is a cupping to hold the marble. Screw the threaded end into a 1/4" coupling and than on to the adaptor on the motor shaft. You now have a grinding/pre-polish, trouble free head that will do several marbles.
This size machine isn't large enough to work on marbles bigger than 1 1/2". In order to work on the marbles, say from 1" up to 1 1/2" it's best to use bell reducers. For instance, if you are going to work on a marble that is 1 1/2", I use bell reducers that measure 1/2" by 1/4". Of course the 1/4" end will screws onto the adaptor leaving the 1/2" end as your grinding heads. If I'm working on a marble that is 1" I use the 1/4" by 3/8" bell reducers and so on. Don't be afraid to experiment with the various sizes.
I will be glad to answer as many questions as I can. If I don't have the answer, I'll find it. I can call on my mentor (Ed Junker) and between the two of us we can come up with the answers. Remember there is no such thing as a stupid question, so don't be afraid to ask a question.
One question that has been asked was why two pickup chains are on the machine in the pictures. There are a couple of reasons for this. Sometimes the marble just won't turn right unless the uprights are to straight up to keep the chain running next to the marble and by adding more chains it will force them where I want them. Another reason is some times the material is to thick for one chain to turn fast enough (another answer to this is to pour off some on the material in the cup and add more anti-freeze to thin it down).
Another question: Do you have to stay right with the machine while a marble is turning in it. The answer is no. Once you have mastered the machine (I wonder if we ever do) you don't have to be there for periods of time. I check on my machines as a general rule about every 15-20 minutes. Sometimes with a big marble that is badly hurt and will require lots of time in the machine, I'll check on it about every hour.
The only thing I will add is that the motors/capacitors have to be wired in parallel. That means that the cord you use for the 115 volt supply should be wired to all the motors, so when you plug it in, you start all the motors at once. Another option would be to wire in a switch on the base plate of the machine. I assume that all the motors should rotate in the same direction.
To wire in a switch is simple. Just cut one of the 115 volt wires and put one wire on one terminal of the switch, and the other wire on the other terminal and then on to the motors. The other wire will remain unbroken and follow through to the motors.
I suggest you do this with the cord unplugged unless you would like to take the chance of having your zipper welded shut.
A word about the feet or legs under the base of the machine. 1"x2"X3" or 1"x4"x3" will work just fine. Place them centered directly under the motor uprights. Before you do, cut a 1/4" or 3/8" groove in them about 1/2" deep. Than nail or screw them under the base. Make sure that the outside edge is even with the outside edge of the base. You may mount them with the groove up or down. This groove will hold the wiring coming out to the motors. I have them both ways, but prefer the groove down. This keeps anything from collecting in them. All wiring will meet at the center of the underside of the base and can be fastened into position.
Don't forget that the hinges have to be welded onto the bottom of the uprights.
Bruce,
Here's a few pictures of the machine from different angles. You should be able to do this in a larger version with your bigger motors. I will have to send the MS Word .DOC file from my office, I don't have it here at home.
Here is some info on the grits I use: I purchase from Ebersole Lapidary Supply in Wichita, KS.
220 faceting grit is 100% virgin silicon carbide abrasive grain. It is harder, sharper and faster cutting
action than most other grits. use with anti-freeze.
1000 grit is the same as above. Use with anti-freeze.
Polishing compound for final polish. Super rapid aluminum oxide. Use with water.
I use McMaster-Carr to buy all my brass compression fittings.
www.mcmaster.com
Let me know if you need any more info. Talk to you soon.
Craig
1. 220, 1000, and final polish compounds.
2. Large rubber bands.
3. Small chain from hardware store. Need enough chain for each grit.
4. ¼" pipe nipples & ¼" pipe couplings. Black steel is fine.
5. 3/8" and larger wood dowel rods from hardware store.
6. Additional brass flex couplings for each grit. (9 total)
7. Three old coffee cups or plastic cups to hold the grit.
8. Anti-freeze to mix the grit with.
9. Ultra-Sonic jewelry cleaner. (Nice one) Clean your marbles with it after polishing to get white grit deposits off marble.
TIPS
1. Keep the distance between motors evenly spaced. Look at the distance the back of the motor support is from the edge of the base. This should be equal all the way around for each motor base.
2. Always seal the brass compression fitting with silicone. There is a small hole in the middle of the fitting. Seal it up. This prevents grit from getting onto the motor shaft. This will extend the life of your motors.
3. Experiment with wood dowel sizes. I use two ½" or so dowels and one ¾' dowel for most marbles. This helps hold it in easier, and also puts more wood on the marble for a better finish.
4. Use 1 or 2 rubber bands for tension. If one doesn't seem to be enough, just add another with it. Don't get is too tight so as not to bind up the motors.
5. How much time for each grit? 220 - 10 minutes to ? Check the marble every 10-15 minutes to see if your are down far enough. I usually rinse and dry the marble to check the progress. 1000 grit - 1 hour Final polish grit - 1 hour to 1 ½ hour. Again, check the marble to make sure it's coming along ok. Stir your grit regularly.
6. If the marble you are working on is out of round to begin with, it may stay that way. You can't always take off enough glass to get it perfectly round.
7. Make sure your marble is turning every which way in the heads. If it is only turning two directions, it can make the marble out of round. I make slight adjustments to the rubber bands every 15 minutes or so to make it turn just a bit in a different direction to prevent this.
How to Shop 
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Linear Mode
