A little backstory, if you don't mind, for context
Or you can just skip to past to the "---- Question Stars Here ---- " line
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So, a couple days ago, I was getting bored of the slow pace and getting sore and tired of all the dust while make slabs of hard minerals (jasper, for example) from my rock collection with my angle grinder and diamond pads. That is, my normal process is that I cut my pieces first with a tile saw, but there's usually some unevenness in the sawing, and there are plenty of pieces that have to be sawn from multiple angles due to their size or shape or can't be properly sawn at all, means having to grind down through several millimeters (maybe to upwards of a centimeter) of unevenness before I can give them a proper polish. And sawing is a messy process on its own
So, I build myself a homebuilt automated slab grinder - rigged and tension-loaded the grinder, built a safety cage out of a bird cage, with plastic to control the dust, bolts to help hold slabs in place, a tray of water to catch the dust, etc. It worked... "okay", about as well as you'd expect for a first-generation prototype at least
I had been coming up with all sorts of ideas for an improved version - three times more powerful grinder, 15cm/6" discs instead of 10cm/4", a cooling system for both the grinder and specimens, soundproofing, a ratcheting net to hold the samples better against the disc, etc. So when on the third night of testing two of the support wires on my grinder broke, I figured that now was the time to make "version 2.0" But when I took my grinder out I noticed it was leaking oil. I'd only been running it through maybe a 25% duty cycle to give it time to cool, yet it still looked unhappy. Even though the new version would have a cooling system and stronger motor, it sort of shook my confidence in its potential longevity, whether one really can use angle grinders like this.
Sooo.... instead of just rushing off to try the new approach...
---- Question Starts Here ----
.... I'm wanting to learn more about what "proper" lapidary solutions are out there
I mean, I know there's flat laps; although the pictures I've seen show people holding their pieces against it, which is not something I want to have to do (although I could rig up a system to hold them), and a lot seem to have a "spike" in the center which would limit the size of pieces I could polish (again, I'm making slabs and some of my specimens are kind of large, I don't want to be constrained to a tiny work area).
My needs are:
1) Price - unfortunately - is an issue. Anything I buy will have its price nearly doubled by shipping and customs by the time it reaches me (I live in Iceland).
2) Size is important - but of course, anything helps. Space to smooth off, say, a circle 30cm (12") in diameter would probably be big enough for 97% of my specimens, including my largest (and neatest) specimens. 15cm (6") would be enough for 90% of them, 10cm (4") for 75% of them, 7,5cm (3") for 55% of my needs, 5cm (2") for about 30% of them, and so on down.
3) I don't want to have to stand over the thing for hours, so a provided solution for holding specimens in place would be ideal - but I can jury-rig something if need be.
4) It doesn't need to be fast - it can take a couple days to smooth the side of a specimen for all I care. So long as I don't have to stand there the whole time.
5) Noise and dust do matter - but I can also rig up solutions to deal with them as needed.
6) 220-250V. I can use devices through power converters, but I really prefer not to - they're unreliable, they tend to cause ground faults, they're heavy (and thus expensive to ship), etc.
So... what should I know?