[lithium]

I forget if I posted this when I first built it in 2004 but in case someone might benefit from seeing it I'm posting some pictures of the design.



several more pictures http://www.zev.dk/misc/CNC/CNC2004.zip

it's just 20x20x2mm steel tube, base is 30x30x2mm tube. cheap roller skate ball bearings on 8mm bolts with 3 washers for distancing. I hand drilled the holes but you can make a rig with a ball bearing holding the drill bit in place so it's precise. some of the bearings where I needed a bit of adjustment for tensioning I drilled the hole oversize and used a nut on the backside instead of thread in the tube as most of them are. once the right position is found the nut can be welded to the tube so it's easy to take it apart and reasssemble later. the stepper motor controller I chose was relatively bad, slow weak and didn't have software for interfacing with cad software. but has to be something better around today.
I used standard threaded rod for the motion. it's somewhat slow because the threading is fine but maybe there are better options like threaded rod for vices and such. or the rod that grunblau used for his mdf cnc.

if you don't have a welder, it's my understanding that one of the very cheap manual feed ones will do plenty. pros use manual feed and they are much cheaper. I bought a disposable CO2 canister system which is also a lot cheaper than industry standard flasks, at least here in denmark where it is cartel overpriced. I forget where I bought it but it was online from england.
seems to be several sellers: in general search for 'disposable co2/gas/welding'
http://www.justoffbase.co.uk/Tool-Sh...-Gas-Cylinders
http://www.shopadilly.co.uk/Auctions...s?cat=&seite=3
http://www.tooled-up.com/MicroCatego...age=2#prodlist

be sure to get a piece of the thin hose and adapter like in my pictures so it can connect to a regular welding gas tube. (regular welding gas tube is what I used for the motor coupling too)
you can use gas less flux welding but I don't much care for that. it's not as nice but can work. not sure about how healthy it is either.

be sure to build an enclosure for the cnc though. once it starts cutting it produces a nasty unhealthy fog of wood dust.

I fitted a 3mm metal cutting tip into the much too fast cheap wood router and it actually worked fine cutting in aluminium. even without cooling lube liquid.

[Avenger454]

I like it. How much does it weigh? Looks like I have some ideas for machine number 2. Or reworking machine number 1. Building a 2'x4' solsylva. That'll get me going then who knows. Already have a decent Mig welder....

[lithium]

not sure. I'm guessing 5kg or so. it's a light structure. doesn't need to be heavy. if one wants more rigidity one can just add a few10x10mm tube struts as triangulation here and there but it seems plenty stiff.

work area is 50x50x10cm

[Mike Everman]

Simple and effective; very nice.

[trouble007]

i am looking at a concept similair to yours and i was just wondering what the accuracy was all in all it looks really good

thanks

Ryan

[Tartan5]

Looks Nice!

How much play are in the linear bearing assemblies? I didn't see any provision for adjustments, and I am wondering how you got the assembly tight enough? Just really precise drilling?

Can you mill aluminium with this? If so, any idea what your accuracy is?

Thanks!
Howard

[lithium]

there is about 0.5mm play in it from side to side depending on direction it cuts. I have no tension on the drive threads and you can probably stiffen the design with a few simple measures here and there and gain much better accuracy.

it's a wood router with an 8mm socket but I bought a 3mm metal bit (6mm socket) and made a crude adapter for it and it actually does well in aluminium. I only tried very little though.