TEMPORARELY OUT OF STOCK!

Manual Stone Crusher
This handy tool will pulverise your stone to fill cracks
and holes when mixed with Opticon 224 resin.
Item #: MSC901
Size: 9.5 x 4 x 4.5 inches
Weight: 5.25 lbs.
Price: $39.95 Another View

Just to be clear; Backer pads must be Milled out in the center and Diamond Pads must be split from the center hole down to the second ring of diamond to work on a sphere machine. Tell me in the checkout "instructions to seller" box if you do NOT want them modified.

This is a photo of Segments welded onto a cup with a rubber foam noise reducer inside.

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Diamond Rod Inventory
Here is what I have in stock:
30/40 mesh = 0
40/50 mesh = 0
50/60 mesh = 0
140/170 mesh = 0
220 mesh = 0
600 mesh = 0 (No Backorder) No longer supplied!
1/16 Inch Bronze 80 mesh = 81
Last updated 10/20/2023

How to use Opticon Resin (224) (Requires Adobe PDF Reader)

DIAMOND BRAZING - FAQ
1. I'm wondering about how many spheres can be ground before discarding or refreshing the diamond.
Answer: It depends! There are many variables to consider.
a. Hardness of the rocks
b. Size of the cups
c. Speed of cup rotation (I recommend between 120 and 200 RPM). I have used this motor with good results: DAYTON 6Z084 AC Gearmotor, 124 rpm, TENV, 115V and Dayton 4Z613 (154RPM).
d. Tension on the cups
e. Mesh size and concentration of diamond in the matrix.
Experience so far has shown that in excess of 50 balls of varying sizes at a minimum can be ground before renewal of course diamond matrix is required using the diamond rods we sell. The fine mesh cups last much longer.
2. Can you apply more diamond as the original brazing wears away or do you have to toss the old brazed cups and replace them completely?
Answer: Once brazed, the cups can be renewed with new diamond practically forever. The second brazed will meld and blend with whatever is leftover from the first braze. The only thing you have to "toss" is the grindings in the drip pan under the cups. I recommend pre-heating your cups before brazing.

3.What diamond mesh size should I use as a roughing grade or should I use a medium grade to try it out first before going completely diamond?
Answer: The rods come in a variety of mesh sizes designed to meet standard lapidary techniques. Here is a list of popular sizes and their uses:
a. 30/40 mesh - Used for course(DR001-1) grinding of soft stones such as Marble, Onyx or Granite. Stones of 5 hardness (Mohs) or less. The reason is that the harder stones will crack and break the diamond bits out of the matrix. You must then re-sharpen the cup using loose grit to expose more diamond.
b. 40/50 mesh - This is a good all around course(DR001-2) grind compromise between speed of cutting and longevity of the cups. Most Lapidary applications can use this mesh size.

c. 50/60 mesh - (DR001-3)Used to course grind harder agates and Petrified Wood. Provides good longevity of cups without excessive scoring of the stone. I've made about 70 spheres of varying sizes before re-brazing is required with this mesh size dependent on the rock hardness.
d. 140/170 mesh - Use as a medium smoothing step (DR002-1) `to remove scratches made by 30/40 mesh grinding if necessary. Use this size to work Jasper that tends to flake and chip. Not needed in most applications.
e. 220 mesh - Use as a medium smoothing step (DR002-2) to remove scratches made by course (40/50, 50/60) mesh grinding if necessary.
f. 600 mesh - (I no longer sell this mesh size) This size will provide a semi-polish before preceding to the final polish. Most of the time I've been able to go directly from course grind to this mesh with great results. It's amazing how much slurry is produced by the 600 mesh cups rotating at 157 RPM. Be aware that the metal cups will scratch some stones. I have converted to using Diamond pads now. I find that metal cups scrach most rocks.

4. I have my own torch and have some existing worn-in cups. Can they be brazed?
Answer: Yes! Standard brazing techniques are used to apply the rod to the steel cups. A word of CAUTION! Do not braze GALVANIZED cups without using the proper breathing (Carbon Filtered) mask. Galvanized cups heated with a torch produce toxic fumes. Try to remove as much of the galvanize as possible before heating.

5. Do the grinding cups need to be beveled inside?
Answer: The cups will perform better and are easier to adjust if beveled before brazing. I recommend a 22 degree angle about 5/16's of an inch wide inside the cup. You can simply pre-grind the cup using silicon carbide until you get the desired beveled surface. Otherwise, visit your local Mill Shop.

6. How well do I have to make the weld on the cup?
Answer: The weld doesn't have to be pretty or even smooth. The wear from the stone you are grinding will soon make the surface very smooth. It will take several spheres of various sizes to smooth out the weld from edge to edge. A diamond rod deposit depth of at least 1/8th inch is recommended.

7. How do I tell when to renew the diamond braze?
Answer: When you see the steel cup surface breaking through the matrix it's time to re-braze the cup. In most cases the bottom inside will wear through first (Point of most wear). The cup will still grind on a larger sphere until you see the steel underneath breaking through.

8. My cups seem to have stopped cutting. What's wrong?
Answer: Just as in the case of a dull diamond saw blade, the cups will sometimes glaze over after excess pressure is used and new diamond needs to be exposed. Simply apply a few shakes of silicon carbide of the same mesh size as the cups to expose more (new) diamond. Once you see the slurry return after the S/C has washed away you have applied enough loose grit to sharpen the cups. This should not be necessary very often. Another effective way of getting the cups to cut once more is to put in a different sized ball. I've found that this helps keep the wear more even as well. Be aware that diamonds never wear out; they crack and break into little pieces and then fall out of the matrix material. If you see a lot of empty holes on your cup the diamonds have been shattered. This means you might be applying too much pressure on the cups.

9. How much water should I use on the sphere during grinding and polishing?
Answer: You need to keep a steady drip on the sphere during grinding to flush out the loose particles during the grinding phase. If the sphere is covered with slurry then you need to increase the drip just a bit. When polishing I start out with a light drip on the sphere using Velcro diamond pads and adapters (see above) or cut pieces inside of PVC pipe cups. After the spots are gone, I start with 200 or 300 mesh advancing to 500 , 1000, 1500 for about 20 minutes each step and then 3000. After a half hour the sphere should have a bright polish at 3000 mesh pads. You can go higher in mesh size but the result is sometimes hard to see any improvement in the shine. I''ve been experimenting with 8000 mesh & DF pads and I like the results I'm getting. I have found that pads labeled DF provide a superior shine on any sphere.

10. How many rods will it take to braze my cups?
Answer: It depends on the cup size and depth of weld deposit. I generally put 1/8th inch deep welds on approximately 5/16th inch wide beveled cups which takes 1 rod per cup for 1 ¼ inch cups. It takes about 1.25 to 2 rods to braze each 2 inch cup but you can go a little thinner on the depth and stretch it out. The rods are 15 inches long for all mesh sizes. Please call (see the "About Us" tab on the Home Page) if you have more questions concerning the brazing process. The size I'm referring to is the pipe size number stamped on the reducer.

11. Why does the cup wear through in just one spot (usually near the bottom of the circle)?
Answer: Unless you grind several different size spheres over time the abrasive diamond matrix will be depleted in a single spot on the cup ring. A small sphere size relative to the cup size will wear on the inner part of the cup were as a larger sphere size will wear on the outer ring of the cup. Even though the matrix has worn through in a particular spot, the cup will still work on a different sized sphere.

12. I have been xperimenting with JB Weld epoxy to attach Core Bit segments and my results are not that good. It works pretty well on smooth rocks but they become detached if the sphere has points or uneven surfaces. I've decided it is not reliable enough to use on a commercial basis; Therefore all my cups made for customers will be bronze welded.

This is a diagram of the jig I use to make my preforms from a square cube into a facetted ball in a 24 inch or 18 inch saw.
The Jig base plate should be 1/4 inch steel.

Cube Cutting Chart