The wet/dry grinder at HD or Harbor Freight is for tool sharpening...the dry side is like a standard bench grinder and turns at 3450rpm , the wet side turns very slow at about 60rpm. The wet stone gets lopsided if the water trough is left full. You would
NOT be happy using this.
$60.00
This may work better depending on what stones will fit it. This is made for wet grinding: Notice the water cups and tray.
$130.00
Search craigslist or ebay for lapidary grinder.
You could use the original bench grinder pictured (at top of thread) with modifications...splash sheild, water tray and drip cups.