I have two very different projects that I would like the communities thoughts and recommendations on:
First, has anyone tried cutting marble on an Altmill? What bits would you recommend for such an endeavor? In my case I am cutting a 1" thick slab that I dumpster dived. My first plan was to use the altmill to cut a plywood pattern, use that to rough cut the marble to shape with a diamond blade in a tile saw, then use the pattern with a 3.5hp plunge router and guide with a diamond bit. But then I started wondering “Why not try to cut it right on the machine?”. I was told by someone far more experienced than I that was a dumb thought but I was interested in what this community thinks or has experienced.
Second project is two inch thick closed cell polyethylene foam that I need to cut inserts out that will fit in a particular shaped steel fabrication that I am working on. Any recommendations on bits, feeds and speeds that have worked for you?
My thoughts on the first question: ‘someone’ was right. Using the mill is a stupid move for two reasons - for one, you will generate a tremendous amount of abrasive dust and even with perfect dust collection, I would not risk my mill for that. Using a (preferably) old and tired plunge router seems to be a smarter idea (while smarter, I still think it’s not smart)
You would want to wear a space suit with positive air supply unless you like the idea of a damaged lung. Water cooling would be ideal.
I suppose flowing water coolant on the mill would be ok if you can find an authoritative source for speeds and feeds …
Phewww, marble. Isn’t that like hard stuff? I have done slate -not on the mill, mind you except for lasering- but I did need to cut it to fit pockets and I can tell you, stone does dust like nothing else. It is easy to solve though. Keep it wetwetwet. Stone does not care being soaked, and dust does not dust quite as much when wet.
But slate aint marble. You only kinda need to cut slate where you want it to break, hit it with a hammer and bobs yer uncle. Marble is another beast.
Maybe look intomhow pros handle this material and test small poeces to see if you are able to even scratch it with power tools. I would not use the mill untill you have a reasonable idea on what’s needed to work this material. Cooling, dust mitigation, tooling etcetera. Only when you can work it with hand helds, you can get a feel for what it would do on yer machine and what you need it to do, to not break down on ya.
@McDarrin Is this cultured marble or real marble? The answer won’t really change my opinion of this project. I’m just curious. Unless you have a closed “box” for your Altmill and a water flood system, this is a very bad idea. Take a look at the commercial operations that cut this stuff and you will realize why.
As to the foam, you may want to take a look at this
I’ve cut thin foam with a drag knife, but my setup would not touch anything 2" thick.
Good luck. I have a feeling that you’re going to need it.
It’s harder than most woods, but as far as stone goes it is not bad. Much softer than granite for example. I’ve looked into how the pro’s do it and there are router bits made just for this type of work. For me the deciding negative factor is the abrasive dust all over the machine would necessitate a complete clean and relube.
Unless you have a closed “box” for your Altmill and a water flood system, this is a very bad idea. Take a look at the commercial operations that cut this stuff and you will realize why.