Turning Marble?

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mbroberg

mbroberg

IAP Activities Manager, Emeritus
Joined
Mar 9, 2009
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Location
Columbus, OH
Has anyone ever tried to turn marble. I was asked today if I could. I said I don't think so, but I'd ask the panel of experts.
 
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You'd need a coring bit to dril it and the vibration would cause it to shatter..... Granite same thing... You can print a picture of the marble wrap the tube and cast in in acrylic..... Soapstone is lower on the MOH scale and is drilled and turned very easily.... theres a section under articles at woodturningonline.com carbide tipped tools and watch your speed. also there is a guy named spike that makes a ton of money that has a 3 part video on youtube which is very informative... and if you email him any questions he will get back to you very quickly.. Cheers
 
Thanks for the information. That's about what I assumed would happen, but having never actually tried it I wasn't sure. The person who asked has a big slab of marble and thought I could make a pen or two.
 
I have tried granite on a metal lathe and could not get it to work. May do it again some other time. I have done soapstone and alabaster and those were fun. I like trustone better and it is easier on tools.
 
No doubt marble can be turned as I have seen some beautiful marble columns. I suspect it is ground with a wet stone rather than use common turning tools. Water cooled diamond core bits for drilling. Maybe a nice pen rest?
 
Marble

Marble can absolutely be turned!! I have extensive experience in lapidary and would not hesitate to give it a try. It is fairly soft (3 to 4 on the Moh's scale). It will respond best to being "ground" rather than "scraped".

Here is how I would proceed.

Cut the blank to length (diamond saw WET)
Drill the blank (diamond drill Wet and COOL)
Cement the tube as usual
Install and remove the pressed in parts that will end up in the final pen (this will pre-stretch the brass tubing and help assure a lower probability of cracking on final assembly.
Take the center part out of the proper size end mill and insert it into a diamond coring bit that is just a little larger (i.d.) than your finished pen barrel. You will want a coring bit that uses a 1/4" pilot bit.

Using a drill press and vice cut the "core" from the blank. The end mill center should keep you centered in the stone and you should end up with a nice cylinder. Use high speed and lots of water (keep it COOL). You will probably have to work for both ends.

Square the ends (on a belt sander?) keep it wet and cool (notice a trend here?)

Mount the bland on the lathe. A mandrel should work fine but between centers would be my choice.

Now simply sand it to size using any paper or tool that will work wet. Diamond "files" or "hones" would work for roughing and sizing. hen work up through the grit sizes as normal.

Keep in mind that with wood you can be a little sloppy between grits because scratches are fairly easy to remove. Not so with stone. Make sure that you have removed all marks from the previous grit before moving on. I would use my micro mesh to finish up.

Let me know how it goes. I may just give this a try myself!!!
 
This really has me intrigued. There is a little expense for the wed saw, saws, bits and what ever, but the results have got to be phenomenal. Are there any photos that can be shared? Sounds like a paradox; sounds so good, but will it look right?
 
Mike: Get a back issue of Woodturning Design (www.woodturningdesign.com) # 20 Winter 2009. You can buy back issues at a reasonable price! It has an excelent article by Steve "Spike" Finch on how to turn stone. You can look over the content of there back issues on line, and will find quite a number of articles by members of the IAP plus others, on pen turning, casting, and finishing. You can get a real deal if you buy back issues by 10-20- or 30 at a time. I have purchased all issues and found them very interesting, even after 50+ years of woodworking!! You realy can teach an old dog new tricks. Jim S
P.S. I just posted a new article on making molds for casting if you are interested. Look under "library-casting-Simple and easy mold making".
 
Jgrden said:
This really has me intrigued. There is a little expense for the wed saw, saws, bits and what ever, but the results have got to be phenomenal. Are there any photos that can be shared? Sounds like a paradox; sounds so good, but will it look right?
Click to expand...

I have both the large 10" tile saw from Harbor Fright, and the small 7" that is always on sale. The blades are ok but are cheap enough if you are cutting softer material they will last. I haven't used the 7" yet one of them deals we I bought it and yet to get to it:biggrin: when using the saws.

One trick I learned from the tile/stone guys when I was a Facilities Manager. Keep the water clean a larger bucket so you aren't pumping grit back into the blade. Or change it often and let the blade do the work or don't force the stone into the work. I have cut marble both natural and cultured softer than natural.

From my lapidary experience I agree with what"jeweler53" said. They turn the spheres with a 3 axis grinding machine. They do make a carbide impregnated file for tile work. That would work for roughing but I think a carbide insert would work since the carbide is about a 9 on the scale of hardness.

You can make your own core drills out of copper or brass tube with some notches cut in the bottom end you mix a slurry of grit and kerosene or water and then have a dam around the bit and slurry drill at a slower speed and light downward pressure, Clear often and refresh the slurry mix.

It id old school lapidary, before all the fancy tools came about.
:clown:
 
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