Cutting Slate?

[rgbrown@itexas.net]

Has anyone out in this Cyber-world use a ShopBot to cut slate or other stone material?

For a proposed project I will need to surface some slate. The client has other projects in mind also.

Ron Brown - rgbrown@itexas.net (mailto:rgbrown@itexas.net)

If Stupidity got us into this mess,
then why can't it get us out? - Will Rogers

[gerald_d]

Ron, do a keyword search on "slate stone" - you will find the button over here:
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[tucker-52@charter.net]

HELLO EVERYBODY!

I've been off of the forum for a while, trying to get my ducks in a row. I've been shopping for a used ShopBot all this time without much luck until last week. I found one (or it found me) about 10 minutes from my house. A real nice fellow (Pat Jackson) has sold me his machine. His wife wants it out of the garage (HA!) and he figured out that he would be just as well selling it and subbing his work out, which he will sub to me. He has agreed for me to leave the machine at his place while he trains me on the basics. I couldn't be luckier. Several folks I know in the sign business have promised me thier work as well.

I have a lot to learn and was determined not to get back on this forum until I owned a machine.
Well, I'm finally a BotHead and I'm thrilled about it.

I'd like to say a special HELLO to Gerald D., Bruce Clark, Ron B., Ron V., (I still want your service, Ron V.) and others whose names I can't remember who have encouraged me and lent good advice. I hope I can count on you guys in the future for problem solving. This forum is why I HAD to go ShopBot!

My Best to You All!

Mark Tucker

[Mayo]

What did you mean by "surface some slate"?
If you mean to make it smooth surfaced and parallel to your table top, it may be difficult since slate is comprised of layers or sheets that will want to flake off rather than machine nicely.

Having said that, I have engraved one test piece of slate floor tile (12"x12"). I used a solid carbide roto-zip bit which is made for tile and I kept both the surface of the slate and the bit wet with water by using a spray bottle. The router air flow will quickly evaporate any water, so keep an eye on it and keep it wet. The slate dust turns to mud which can be washed away when you're done.

If I remember correctly, my cutting speed was probably .5" per second - can't remember and I didn't write it down. I cut about .125" deep in one pass. You'll also want to slow down the z movement so it doesn't shatter the slate or the bit from making contact too fast and hard.

On one letter that was engraved, (a lower case e) the center of the letter flew off but I was able to glue it back in place. The only other problem was obtaining an even depth since the surface of my sample tile was so irregular.

[rgbrown@itexas.net]

Mayo,

I have since learned I can go to the 'big city' - about a 200 mile trip and buy "gauged slate". But, before I found that out, I took an old chipped bit and did some testing.

1/2" bit; 1.5 ips; >.030 cut; 10,000 rpm worked fine - dry and dusty. If I had not been able to get the gauged slate, I planned on using an insert bit from Her-Saf ( http://www.hersaf.com/ ) and using some different inserts with angle changes and harder carbide to handle the properties of the slate.

BTW, I am beginning to really like the insert bits. I get a 'new' edge for less than a dollar on the smaller straight edge bits and the cutting diameter stays the same. It takes less than 30 seconds to change bit profiles or edges.

Ron Brown - rgbrown@itexas.net (mailto:rgbrown@itexas.net)

If Stupidity got us into this mess,
then why can't it get us out? - Will Rogers