How to drill a hole in a cabochon or slab

by Bruce Frymire Sep 10, 2017 0 comments

Start with a small drill bit (3/4 to 1 mm), lightly touch the stone until the hole is started.  Use a little pressure but not enough to bend the shaft of the bit.

Don't drill to fast or force the bit, these small bits can break easily.  If it breaks off in the hole you may not get it back out unless you have a hollow drill bit.

As you drill, move the bit in and out of the hole in order to fill the hole with water, this helps to keep the stone cool and flushes out any waste from the drilling.

Getting it hot, drilling too close to the edge and using large bits first can cause breakage, also drilling on a fracture line may also cause the stone to break.  

After drilling with the 3/4 mm bit you can increase to a larger diamond drill bit.  Use the smallest in the set first.  You are going to gradually increase the hole by using different size drill bits.  As your drilling you can feel the bit stop when it finally touches the glass plate.  

Just go slowly and you shouldn't have a problem.  

After the hole is finished, use a small ball bit and smooth out the edges of the hole.

If you glued your stone to the pyrex plate pour a small amount of acetone to cover the stone and let set until the stone is free.  Probably less than an hour.

Safety rules, use eye protectors, don't immerse the Dremel in the water, especially if it's electric  and remember you're drilling the stone not your finger. 

Dry your dremel:  Very Important:  Using the dremel around water will cause contacts to corrode, dry the the dremel after you're done.  I use a hair dryer.   If the contacts corrode you may be able to remove it with baking soda and hot water and a wire brush.