Thunderegg Cutting Jig

I needed a quick way to cut the small eggs. At first, I simply screwed a door hinge to two 2 x 4
inch x 2 feet long boards. It worked like a giant alligator clip. That worked so well, I C-clamped two bronze bearings onto the back of the frame. I put a shaft through the bearings and welded an angle iron which was really a bed railing I got out of the Quartzsite city dump. I C-clamped a square of tough cola box wood to the angle iron so the center of the saw blade edge came down flush with the box wood and put a weight on the end to hold the clamp down. All I had to do is take one rock out by lifting the angle iron and put the next one in, being sure that two points of the rock made contact with the 2 x 6 inch board at the bottom. That was enough to keep the rock from wiggling loose. All I needed was one good point for the box wood vise to bite into, then I turned the blade on and let it gently get a good start then let go. I still have that saw today and I can change a cut rock with the next one in about 10 seconds! And, I have never ruined a saw blade in the 37 years I have used it.

I have found Raytech’s continuous rim Black Blazer saw blades to be best. Now, imagine cutting a 6 inch in diameter rock with a 14 inch blade. The secret is to violate the specifications. I don’t use a collar that is
“required” to be one fourth the diameter of the blade. On a 14 inch blade, the collars would have to be 31/2 inches in diameter. I use 2 inch collars which gives me 6 inches before the collar makes contact with the rock. I put a C clamp on the front of the frame to stop the saw just before the rock would make contact with the collar. This also serves to minimize the size of the tit that breaks off the rock when the sawing is
finished.

Now again, imagine cutting a rock 6 inches wide but 7 to 8 inches long! When the vise handle hits the
C-clamp, I turn the saw off and lift the angle iron-box wood vise just enough to pull the rock forward and/or
000 (Page 12 for July, 2007) rotate it WHILE THE SAW IS STILL IN THE ROCK. CUT. After the adjustment, I hold the vise up and rotate the saw to be sure the blade is free to move and that prevents big saw groves that result trying to rotate a rock in a standard vise. Most times, I can move the saw up and down while the vise is held up just enough that the rock is loose and the saw blade will adjust the rock perfectly. Other times, I have to rotate the rock to get the same result. And the result after the cut is finished, is very little to no saw marks! It was running when I got the images off the Time Machine monitor. The over spray shields hide the egg being cut.



In the second image is the backside showing the double bucket pumping system. The kerosene and mud from the rock cut exits through a 1 x 4 inch pipe nipple into the primary bucket. When it gets 2/3 full of mud, all you need is a soup ladle to dip the mud out into another bucket.

(The mud is saturated with kerosene and I put it in a pants leg tied off on the bottom. Pour the mud
in and hang the pants leg on a hefty hook above a clean bucket. You will recover a lot of kerosene doing that.
After it stops dripping, just squeeze the pants leg by turning it on the hook and you will get more. Then dump
the mud in a large pan to dry it. Once dry, the powdery mud makes a healthy medium for your garden. Since
thundereggs are rhyolitic, using it on plants that like a little acid in their diet is best. It has the same chemical makeup as the “popped” perlite gardeners use on their plants.)
There is an outflow pipe nipple that sends clean kerosene into the secondary bucket which has a pump
motor set on two ½ x ½ inch angle iron slots that holds the pump motor that the brass shaft housing slides into.
The bronze impeller at the bottom of the brass housing is held up a few inches from the bottom of the
secondary bucket. When the mud and rock chips run out into the primary bucket, it quickly settles to the
bottom. The kerosene separates clean and rises to the level of the pipe which runs from near the top of the
primary bucket into the secondary bucket. A cotton T-shirt is cut so it can be wrapped around the bronze
impeller housing which keeps any insects from getting into the feed tube and pipe which would clog the it up
and cause the saw to run dry and warp, but I have a “clutch” mechanism that prevents the saw from being
ruined. A saw blade can warp a bit without being ruined..
Now, to put a clutch in, I violate the specifications again. The specs call for a 14 inch blade to run
about 800 to 1000 RPM. Mine runs at about 350 RPM! I have a 11/2 inch pulley on the motor and a 5 inch
pulley on the saw shaft. If the kerosene feed pipes clog up, the blade dries and warps. But, before it gets hot
enough to ruin the blade, the warping stops the saw instantly. The small pulley on the motor cant drive the
5 inch pulley on the blade shaft and the saw stops. The motor is still running and either you hear it instantly
or the pulley will squeal. If that is ignored, the worse that can happen is ruining the belt and/or the small
pulley. This is a cost effective way, even for idiots. A new 1.5 inch pulley and burnt belt can be replaced for
about $15.00. A new saw blade costs 230.00. (I buy my 14 inch Raytech Black Blazer from
<cyberrockhound.com> or phone (712) 202-1622. If you get Brian Jackson on the phone, tell him that the
Geode Kid recommended Cyber Rockhound and your order will be filled immediately).