Quick tips 4

The subject of this months quick tips is hole drilling.  I hope you find the points of use.

• make sure you mark out the holes in the right locations on both sides of the stone.  It is so easy to make a mistake and to potentially spoil a piece of work.  Yes, it still happens to me occasionally!
  
• rest your  hand to steady the handpiece
  
• begin your hole by placing the burr at a 30 degree angle to the face and making a small indentation or socket.  You can use a small ball-shaped burr for this step, or use the tip of a longer, tapered burr with which you'll drill the hole
  
• begin the hole with the thinnest tipped burr you have.  Hold the handpiece in an upright position, in line with the intended direction of the hole.  A smaller tip means less resistance so you drill the pilot hole more easily
  
• as you drill, make sure there is an adequate supply of water to cool the burr & rock and to clear the rock flour.  This can be a mere drip every second for a small hole
  
• OK, an apology!  I'm probably using the term "rock flour" in a loose sense because strictly, it is only produced by a glacier grinding on the valley & mountain rocks underneath.  It's what is then washed out and turns those mountain rivers a beautiful bright blue colour.  I'm open to suggestions as to what I should be calling the clay-like substance that is produced by the grinding of a burr on jade!
  
• As you drill ahead, use a corkscrew-like wrist movement to create a slightly larger hole  than would otherwise be made to prevent the burr from binding in the tight hole
  
• alternatively, use a repeated prodding and lifting-off of the burr from the stone
  
• use progressively larger burrs until your hole is the desired diameter
  
• drill in from both sides of the rock to prevent blow-out of the face.  Meeting in the middle is a bit of an art but you'll get used to it with practice!
  
• as you near breakthrough between the holes, you'll hear the rock "sing" - it is a beautiful sound - and then as you reach the other hole there will often be a surge in the amount of rock flour and the tone drops to a dull grinding sound.  At this point you reduce the pressure so as to avoid the burr driving into the other hole and binding.  Be alert!
  
• enough for this month?  OK!
  

Enjoy your carving!