Drilling/turning stone

[Chasper]

I'm attempting (and so far failing) to turn pens from stone. I'm working with banded sandstone, alabaster, soapstone, pipestone and whatever else comes along (all relative soft stone, maybe Mohs 5 and under). I have all of this stone on hand because I use it to carve knife handles.

What I thought I would do was to drill out pen blanks, mount them on my mandrel, and uses a combination of angle grinder, rasp, file and sand paper to work them down. I'm using a basic Jet pen turning lathe.

I got as far as the drilling; about half way through the second half of a blank of Minnesota pipestone. The stone got hot enough to destroy the bit. I tried slow speed on the drill press, low pressure on the drill (probably not low enough), and dribbling water into the drill hole (it all immediately splashed back into my face).

Diamond core bits are not normally long enough. Would a masonry or glass bit do the job? I'm having trouble finding a 7mm masonry bit?

Assuming I manage to get a hole drilled, can someone tell me how best to grind it down while the lathe turns? Can this even be done on the basic equipment I'm using?

Thanks,
C

 

[DocRon]

I have made a couple of pens from soapstone, but have not tried anything harder. Not much trouble with it. Used a bradpoint bit (that's what I had in the 7 mm size), slow speed, with water cooling on a drill press. Clear the cuttings often. Lathework was mostly with a scaper, at least for final shaping. I remember that I used a 1/2" bowl gouge for the intial cuts. IIRC, I rounded the edges on a belt sander before putting it on the lathe.

I recall a friend telling me he had made some small bowls of alabaster, using scraping techniques. I am guessing sandstone would be difficult since it is more abrasive.
Good luck. Keep us posted on your progress.

 

[Pikebite]

I have also turned pens from soapstone. Used a 7mm masonry bit and turned with a scraper. Not to many problens apart from the cracks in the stone. Used a little thin CA and finished by wet sanding with micromesh.

 

[Chasper]

Thanks for the tips, it looks like it can be done. Soapstone is among the softer stones to carve; probably softer than some types of wood. I have successfull drilled it for other uses. Can anyone tell me where to find a 7mm masonry or glass bit?
C

 

[Hiram33]

I have made several pens, letter openers and others out of alabaster stone ( see my album). I have used mostly Utah alabaster stone take about 4 blanks to get the job done. Drill is the hardest part. I have found the normal wood bits work best. at a slow speed. blank looks good then you find a fracture and star over. Turning can also be tricky. when you get need the end I switch from tools to sand paper. also I have tried Tiger Eye Alabaster lots more quarts and a bit harder blow out are much more common. I also just got a piece of alabaster from Montana and it looks very very quarty's not sure how that will turn. I will let you know

good lick

Peter

 

[Randy_]

Originally posted by Chasper
<br />.....Can anyone tell me where to find a 7mm masonry or glass bit?

A 5/16" bit is only slightly larger than 7mm. I would buy one of those and grind it down slightly to 7mm. Finding metric masonry drilss will probably be difficult.

 

[Randy_]

Originally posted by Chasper
<br />.....The stone got hot enough to destroy the bit. I tried slow speed on the drill press, low pressure on the drill (probably not low enough), and dribbling water into the drill hole (it all immediately splashed back into my face).

I don';t think dribbling a little water on your drill bit is going to solve your heat problem. If you watxch folks drilling srone counter tops or cutting tile, they have a steady stream of water flowing to cool the cutting edge and carry away waste. UI suspect that without professional equipment. drilling the harder stones is going tp be frustrating. Until you get the hang of it, you should probablyt restrict your efforts to the soapstone and alabaster and limestone/

 

[laspringer]

I would use a masonry bit, 1/4" and a rat tail file to finish the hole size. I have made pens out of marble and malachite.
Good luck Alan

 

[rtparso]

Remember some masonry bits are made to work with impact. Some like the glass bits are made to work under rotation only.

 

[Chasper]

I appreciate all of the help, I'll try those recommendations and show you the results. Today is the start of spring break and I'm off on a Colorado rock hunting trip with my sons. I'm planning to come back with some alabaster and jet for turning, maybe some rhodochrosite as well if we can find big enough pieces.

Thanks
C