celt40
noticing nice landscape pebbles
KNIGHTHOOD FOR JOCK STEIN.
Member since July 2009
Posts: 99
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Post by celt40 on Sept 8, 2009 17:31:12 GMT -5
I was thinking of having a go at converting my old dry bench grinder into a wet grind for shaping stone. I know that this might cause a problem of keeping the eletric dry. Also will the speed of the grinder approx 2,920rpm be to fast. The other idea i had was to buy a low priced combination grinder. These have both dry (fast) & wet (slow) grinding. If i used the wet grind it will be properly sealed and the water problem before will not come into it. The wet grind runs at 120rpm will this be too slow? Can you give me your thoughts on this is it a crazy idea or will it work.
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Sept 9, 2009 0:40:44 GMT -5
If you are just shaping before tumbling, I think your old grinder would work. I have one of the combo grinders and tried it on rock before I got my lap. It can grind a rock, but very slowly. Faster would be better.
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celt40
noticing nice landscape pebbles
KNIGHTHOOD FOR JOCK STEIN.
Member since July 2009
Posts: 99
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Post by celt40 on Sept 9, 2009 6:42:20 GMT -5
Scott will i need to use water to cool as this will get hot. I don,t have a combo just now, i will need to buy it. I do have an old grinder that i used to sharpen my woodturning tools. This is the one i want to see if i can use anyway possable.
I have a good wet sharpening system that i now use for my woodturning a Tormek. This is the slow speed stone passing through a water filled trough.
Thanks Dermot.
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
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Post by drjo on Sept 9, 2009 7:00:09 GMT -5
Hey celt40. More things can be pressed into service for something else, but being satisfied with the results is the problem. The speed is about 1000 rpm's too high for most work, you'll have heat build-up quickly and will have to run more water as it will sling off faster. (faster speeds require a lighter touch also). If the unit is a 6"wheel and you can replace them with 8" wheels you will effectively reduce the surface speed. You'll also want SiC (silicon carbide or carborundum) wheels since most grinders come with Aluminum Oxide wheels which don't rough grind rock very well. You can try the unit out as is if you just use a spray bottle for water. Start the unit, then spray the wheel well with water, if you have a third hand (helper) they can keep spraying the wheel while you try a bit of grinding, mind you, this is just to get a feel for the unit, as in 30 seconds ish. If you try this, leave the machine running for a minute afterwards so all the excess water is slung out of the wheel(s)!! (otherwise if you restart the grinder, the wheels will be very out of balance and could break apart)!! A better use may be to replace one of the wheels with a pulley to run an arbor (or mandrel) www.acehardware.com/largeImage/index.jsp?LargeImageURL=http%3A//ACE.imageg.net/graphics/product_images/pACE3-989451dt.jpg (these are double ended) with the the wheels of your choice and control the speed with pulley size. this way you can mount the motor away from the water hazard. (or something like ( forum.rocktumblinghobby.com/index.cgi?board=hmequip&action=display&thread=32981 ) The slow wet grinder is just that...slow. And may have too fine of a grinding wheel for rough shaping. Plus it won't be usable for tools without redressing it. Keep us posted on your progress, especially if you try the unit out as is (take before and after pix of the rock). Good Luck, Dr Joe .
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RockyBlue
fully equipped rock polisher
Go U.K.
Member since June 2006
Posts: 1,719
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Post by RockyBlue on Sept 28, 2009 0:07:40 GMT -5
I have 2 inexpensive grinders that i use,one is set up with the green grinding wheels and the other has buffing wheels on it. DO NOT USE DRY on the grinding wheels with out a shop vac hose hooked to the back of your grinder.I keep a little pan of water sitting by that i put pendants in too keep them cool.i grind about10 sec.at the most then put it in the water and pickup another one and grind on it etc. When grinding this way you have to be very carefull not to get the stones to hot or they will crack especially blue lace agate..........Rocky
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Oct 1, 2009 2:03:50 GMT -5
The old one is probably on the fast side, and when I tried the wet side of a combo unit it ground very very slowly. Always use water when grinding rocks. The dust is really bad for you. en.wikipedia.org/wiki/SilicosisIf your planning on buying why not buy the parts for a flat lap? It would cost about the same to build one as buying a combo unit and you will be much happier with it. Take a look through this section, there are several you could copy.
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