Post by Saskrock on Nov 14, 2007 22:37:24 GMT -5
If anyone is interested in building a sphere cutter I made the one from this web site by Kreigh Tomaszewski.
tomaszewski.net/Kreigh/Minerals/Homemade.shtml
His idea is quite a bit different from the sphere cutters I have seen on the net but works well
Here is a picture of the one I built from his plans.
this is the first sphere I made, it is about 3/4" and the second which is about 1 1/4"
It spins at about 600 rpm, I used steel pipe instead of a copper elbow but it seems to work fine. This was easy to build and took about 4hrs. I used 2 pillow block bearings which held a 1/2" shaft vertical. The top end of the shaft I threaded to 1/2" NC to attach to the cup (reducing swedge) to hold the the rock (try to center as best you can but if the cup wobbles a little it will still work). The bottom of the shaft has a 5" OD pulley which is connected by a belt under the machine to a old furnace motor. I got the motor for free by going to the local heating and air conditioning place and asking if they had any old furnaces waiting to be sent off for scrap. It is 1/2hp 1725 rpm with a 2" pulley. I turned a bucket upside down and used a heat gun to droop it in. This catches any grit that comes off.
It took about 1/2hr to make the small sphere (I don't know what it is but fairly soft maybe 5-6 Mohs) and the larger (Agate) took about 2hrs.
When using the cutter you have to give your rock a little twist with your fingers every 10 seconds or so depending on its hardness or it will cut a groove on the bottom. Otherwise it is very easy to do but it does require constant attention.
tomaszewski.net/Kreigh/Minerals/Homemade.shtml
His idea is quite a bit different from the sphere cutters I have seen on the net but works well
Here is a picture of the one I built from his plans.
this is the first sphere I made, it is about 3/4" and the second which is about 1 1/4"
It spins at about 600 rpm, I used steel pipe instead of a copper elbow but it seems to work fine. This was easy to build and took about 4hrs. I used 2 pillow block bearings which held a 1/2" shaft vertical. The top end of the shaft I threaded to 1/2" NC to attach to the cup (reducing swedge) to hold the the rock (try to center as best you can but if the cup wobbles a little it will still work). The bottom of the shaft has a 5" OD pulley which is connected by a belt under the machine to a old furnace motor. I got the motor for free by going to the local heating and air conditioning place and asking if they had any old furnaces waiting to be sent off for scrap. It is 1/2hp 1725 rpm with a 2" pulley. I turned a bucket upside down and used a heat gun to droop it in. This catches any grit that comes off.
It took about 1/2hr to make the small sphere (I don't know what it is but fairly soft maybe 5-6 Mohs) and the larger (Agate) took about 2hrs.
When using the cutter you have to give your rock a little twist with your fingers every 10 seconds or so depending on its hardness or it will cut a groove on the bottom. Otherwise it is very easy to do but it does require constant attention.