| Morris Dovey wrote:
|| Marble can be machined with CNC routers. I would guess that
|| carbide-tipped bits with 1/2" or larger shanks are used. Spindle
|| and feed speeds would need to be chosen carefully, and there'd
|| need to be an effective cooling system to prevent overheating the
| I'd expect the cutters suitable for even soft stone to be grinding
| cutters, not 'slicing cutters' like those used for wood or metal.
On the ShopBot Forum, at
POST22151 you can see a marble (pet) gravestone that was routed with a
standard 90 degree V-cutter.
There's another discussion of routing marble with a photo at
POST12599 (mind the wrap). Note that in this instance the router was a
Porter Cable running at 10,000 RPM and maximum depth of cut was 0.1".
Between passes, the user softened the marble by wetting it with water
(I just learned a new trick!)
|| My quick search turned up a granite (harder than marble, I think)
|| at http://www.cncmotion.com/granite.htm - which will provide some
|| idea of what the machines look like.
|| Some of my fellow ShopBot owners have used their machines to rout
|| Corian with very nice results - and I'd expect that material is
|| more like marble than granite.
| Isn't corian plastic? E.g. an organic polymer. Hardly comparable
| to rock.
You got the first part right. It's not rock. For routing purposes,
however, it's much like a soft rock (harder than soapstone, softer
DeSoto, Iowa USA
On 2005-09-12 14:05:40 -0400, email@example.com said:
Corian is methyl metacrylate with Aluminum TriHydrate filler. ( and dyes )
When the proper sharp router bit is selected, and the rpm is just
right, the feedrate appropriate for the depth of cut, the bit will
slice/cut the material creating very thin shavings of the cut you're
taking that are light enough to become somewhat air-born in a floaty
sort of way.... that reminds me of me and my sweetie sitting in a Swiss
meadow surrounded by tiny butterflies...
If you're getting 'dust'.. you're 'grinding' turning the ATH white and
leaving a white line. Polyester solid surface countertops will almost
always 'grind' as the stuff is nothing but auto-body filler with
aquarium gravel tossed in for colour..IOW..crap. (You also cannot
eStone, as I call it, (engineered stone) is 93% quartz and 7%
acrylic... sold as Silestone, DuPont Zodiaq, Cambria,
FormicaStone...and many more. You work that stuff the same as
granite(MUCH harder than marble, btw) diamonds and lots of water.
You can't rout marble. A router will cut it (marble is indeed pretty
soft) but a router just doesn't have the rigidity for it. If you have a
shaper (English term) which is like a big table-mounted router at a
slow speed, then you can do it. A spindle moulder (big shaper, with
replaceable knives) has too high a linear speed.
Diamond tooling works fine, but needs water or air blst cooling /
lubrication / dust removal. It's not something you can run in a
You can saw marble either dry, with a diamond sawblade in an angle
grinder, or wet with a diamond tilesaw.
Marble really is pretty soft though. Get a carbide "tile file" and do it
by hand. Then use a piece of tile setter's carbide-grit coated mesh to
smooth it, then plain old silicon carbide wet ad dry paper glued to a
plywood stick (or pulled tight over a cork block) to polish it. Don't
work the paper with your hand, or you'll sand thumblines into it.
OK the outcome. I chickened out on using a router and went with the
grinders. It cut like butter with a medium 4.5 inch grinder wheel and
left bright white if somewhat rough edge. I then hit it with a medium
grit sanding disk with the little overlapping flaps. It smoothed it OK
but burnt it a bit. I used no cooling just moved the grinder. I had
three edges to do, two about 2" long to match an existing ogee and the
third about 12" which was a straight cut. The first try on small edge
is OK, the second came out real good & will be the front. I just
beveled the remaining side for now.
The next problem was the existing piece was an antique "tea with creme"
color and the new edges were bright white so it didn't matter how close
the cut was, it still stood out like a sore thumb. Ten minutes later
and a quarter can of Comet cleanser, it all blended together. Based on
how the Comet erased the burn marks, I think I'll tune it up at my
leisure with a profile sander and silicon carbide paper. So I never
tried routing, but for that adventureous soul out there...it might
Thanks for all the advice.
Hmm, I guess the burn marks were from materials in the sandpaper,
like the adhesive that holds the grit onto the paper. Makes you
wonder if similar burn marks on wood (from power sanding--not
power sawing) might be cleanable with solvent.
This is very disappointing news. With all the conversation on the subject,
we needed something more dramatic. Shattering table tops, holes blown in
the walls from flying chips, tools exploding.
Simple tools and it worked. bummer.
I wasn't going to respond to this thread since I didn't want anyone to get
hurt trying this, buttttt, I did put a 3/8 roundover on a slab of marble
with a router and a carbide bit about two years ago. I used a bit that was
about to be trashcanned anyway(cheapie), and an old crapsman router(my first
router, what did I know). I did it freehand and dry. The only problem was
the dust storm it made. A little polishing and it turmed out great. I now
have an MK 10" wetsaw and a diamond profile wheel so I wont be doing that
On 2005-09-13 00:06:23 -0400, "JERALD SMEJKAL"
If any of that dust came from the carbide bit, cheapie or not, I hope
you had a mask on your face.
According to my sharpener, carbide dust has cobalt in it and will hurt
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