Drill bit for slate

[martin35]

Hi guys

I want to add some fixation screw holes in my table slate (there is only 4 hole per slate) and I wonder which drill bit is use to drill and countersink screw holes in slate. I suppose that a standard concrete bit will work fine for drilling but I wonder what is used for countersink. I was thinking about regrind a concrete bit to 82deg. But I’m still curious to know what professional use.

Thanks

Martin

 

[91design]

I used this ceramic spheric abrasive drill bit

; it worked like a charm(you can't even spot the difference between the originals and the handmade holes), you only need to pay attention when you start to drill the countersink because sometimes the bit tend to slide.
The manufacturer is wolfcraft, it's german. http://www.wolfcraft.it/it/prodotti/p/schleifkoerper/schleifkoerper/s/p/index.html

 

[martin35]

Hello 91design, nice to talk to you again.

Thank you for the tip, we have Wolfcraft tools in North America also, I will try it.

Martin

 

[91design]

Nice to talk to you too, martin
I used this tool to create new countersinked holes on a GC IV Brazilian Slate, so it should be good with pennsylvania slates too.

 

[SlateHumper]

counter sink

Just use a masonry bit several sizes larger to make the counter sink after the initial hole is made. It's a pool table, not the space shuttle