Machine capability and pricing

[coyoteboy]

Hi All,

I hope you don't mind me asking here but it seemed like the most suitable place....

I'm looking at purchasing a Micromill 2000 for home use but I'm not sure if it will really cope with what I'd need it to, and in which case it's a waste of cash I could put towards something bigger (but probably never buy because it's such a large jump in price). I'm looking at 3D milling alu parts around 200x50x100mm absolute max, and not requiring super precision (+-0.1mm would be fine). The question I have is would the micromill cope with such jobs (assuming I didn't have time constraints and took fairly light cuts at high feeds)? I'm concerned about the depth of Z axis movement but I suspect that is going to rely primarily on the length of my cutter and it's flex, but the Z axis on these does concern me regarding stiffness (possibly without cause). I'm only used to working with the likes of large bridgeport manual machines so normally stiffness isn't a problem I encounter.

What sort of cash (UK) should I be paying for one in decent condition, with original software?

Any help appreciated!

[angel-tech]

i would look at either the novamill or the triac.

[coyoteboy]

Hmmm I'd been looking around that size, or converting something larger, but the price really does start to shoot up. I'd be looking at about £450 for the micromill but it seems I'd be looking around 2K for a Triac? I know, I know, you get what you pay for ! Point noted though - is that "it won't do it" or "you'll be struggling"?

[angel-tech]

you would be struggling badly, with the micromill.

bordering on the edge of not possible.

[Denford Admin]

The travels on the Micromill are:
Travel X-=228mm
Travel Y-=130mm
Travel Z-=167mm

So should do what you're thinking of. I think the rigidity should also be OK but it's hard to tell without seeing what you'll be making.
You could always fit a high speed spindle motor and use quality tooling to reduce load on the machine if it can't cope.
I'd bear in mind that the axes aren't that quick and probably even slower if doing 3D, but if time isn't that important (vs the cost of the machine) then I'd be tempted to have a go.
PS if you google "Sherline milling aluminium" then you'll get a good idea what the machine would be capable of
eg: http://www.youtube.com/watch?v=QXduzH2g-zo

[coyoteboy]

The kind of thing I'm thinking of is something akin to 4 pot caliper halves :
http://i82.photobucket.com/albums/j272/ ... d4pot3.jpg

It's within dimensions I admit but I get told pretty consistently that I can't make anything of use without half a ton of cast iron. Seemed to me that I'd only need something fairly small if sticking with soft alloys but I don't have the experience needed with smaller high spindle speed machines. As you say, considering the capital cost and having plenty of time it seems like the best tradeoff but I'm cautious of being caught out by my budget. It seems ideal for a lot of the much smaller stuff I'd like to make (also alloys) but I want the moon on a stick of course! It's certainly not for commercial use, this will be 6 months of me making mistakes and having fun, then making bits that are useful for small hobby robots and a race car I'm building.