How large of a stone are you talking about? That would be a help in giving you advice.
Very small, rough grind it to shape and then tumble it to polish. This can take up to 30 days.
Larger pieces are shaped with pressure cutters. diamond saws, or 'chipping' by hand and chisel.
Any stone (like granite) is worked with diamond wheels/cutters.
The problem with stone is if there are any fractures in the piece you are working.
Like cracks in wood.....these are the rough spots.
Are you close to a monument shop that does it's own engraving/blasting?
If you can talk to them they can be a help.
Boring pieces that are fairly large can be done with a boring maching and diamond hole saws.
Boring a little stone. You might need a diamond cutter that fits a dremel tool.
Very small, take your time, LIGHT pressure and you might be able to do it.
Good luck,
Stoney
I'm sure with a bit of creative brainstorming a water cooled pen lathe setup could be modified/made. Hey farmer, if your ever near Reno, let me know, perhaps we could sit and have a lunch somewhere and brainstorm a bit.
Another thought to consider...
If you're referring to raw stone (as opposed to the resin impregnated stuff commonly used for pens) coolant becomes important, as heat builds up very quickly when abrading stone and can lead to failures of the stone matrix.....(said another way, your piece breaks or flies apart). Often this is accomplished with recirculating water, not complex, but it is an additional important consideration.
Search locally for 'lapidary supply'....a good supply house will introduce you to a whole new world of specialized stone working tools and be able to provide guidance.
Cheers,
Sam
There is a guy on here that does alabaster and granite, GW pens( Ihttp://www.penturners.org/forum/member.php?u=14386) think and they look beautiful. I've tried alabaster with just a skew, you will need good ventilation and breathing mask, go slow because it will heat up and crack and blow up. Alabaster is soft like soap stone turns nice
Can you specify what kind of live cutters or tooling you have? RPM? Shank size or collet size?
Ornamental turners do a lot of this on soft materials (malachite) to hard materials (rock crystal). They do it with diamond wheels and they typically do it wet. Doing it wet may be a problem and also keeping all the rock dust and the errant diamond specks out of your machine ways. These diamond wheels are mounted on a variety of cutting frames to get the cutters in at various angles. Are you just trying to turn a cylindrical blank or get more exotic
Rich
Ok People.
Lets start with the easy parts. Columns are turned on a lathe. The bigger the columns the bigger the lathe. Polishing is also done either by hand or on the lathe. These have water for cooling and a waste trap in the floor. The monument companies have always made designs easier as they went along. So, Square columns became the way most things have been done for the last 40 years. With the use of computers , some of the old styles are starting to come back.
What you are needing is more for the jewerly kind of saw. These are as small as a older portable TV. The stone is 'cut' in oil. That is why they are called "Oil Saws". Jewerly tools is what you are going to need, Grinders like a carving tool size bits. Looking in lapidary is going to give you the very basics which is where you need to start. With a few changes to a faceting maching you might be able to do what you are wanting to do.
These are not cheap.
The hardness of the stone is going to also make a difference. No matter how you go about this.....it will be a challenge.
You might be better off drilling the stone first. Then taking it to what is loosely called a grinding wheel. This has a 'dripping' source of water from the top. There is a pan under the wheel with a siphon connection to allow the water to fall into a pail at your feet. To polish a stone is much like wood. What you are doing is putting smaller and smaller scratches in the stone. This is what happens when when you change the 'grit' size in a tumbler. On a grinder, you use finer and finer wheels till you get to a point where tin oxide or aluminum oxide can be used as a final step. Which one you would use depends on the stone you are polishing.
Good luck Farmer on what you are trying to do. I look forward to seeing what you come up with.
Stoney
When I made my Petoskey Stone Pen, I drilled with a masonry bit, chased with a HSS drill bit (although a boring bar would have worked better), turned it on a metal lathe with a carbide cutter, and then sanded smooth. A true lapidary lathe would use a grinding wheel on the cross-slide rather than a cutting tool.
I hope that helps,
Eric
Looks like your way ahead of me in skills and equipment. I have quite a bit of lapidary equipment, but nothing set up to do cylinder shapes. PM me in Feb, when your going to be in town. I'll see if I can get away for lunch.