Newbie- Planning my CNC mill

[erikjgreen]

Hey all -

General comments on my sanity and my plan so far are appreciated.

I'm getting together parts for my first CNC mill. I've had a HF mini mill for a few years, and a mini lathe and a G4000 lathe for a bit less. I enjoy machining items for gadgets, etc. but I've decided for the stuff I really want to make I either need CNC or to pay to have someone else make it.

Since I'm a hands-on type, I want to CNC things myself.

So I thought to start I'd CNC convert my mini mill. Not having to build my own mill structure and ways seems like a time saver, and although I can't afford one of the nice kits, all the people that have CNC converted the mini mills are a great resource.

I have a local surplus shop I watch for deals. So far I've gotten:

• A pair of Superior Slo-Syn stepper motors, 485 and 585 oz-in torque in NEMA 34
• A pair of "unknown" japanese steppers, 140-ish oz-inch size.. probably too small to use
• Two "Universal Thread" lead screws with nuts... one 14 inch, one 12 inch. I wanted ballscrews, but these were cheap and it turns out they're very very accurate. I also got thrust bearings and some hardened rails in the same box
• A machine to take apart that is 7 feet tall, made of stainless steel, and has limit switches, 2 pneumatic cylinders, solenoid air valves, a nice control panel, a 6 foot ball screw with nut and two 6 foot rails with carriages. It was a tensile strength tester.

The last item is the one that's got me thinking differently now... the machine was made to test up to 250 lb tensile items, so the vertical column is a rectangular box of stainless steel about 6 feet tall by 3 inches by 7 inches. As is, it's very rigid, and it could be filled with polymer cement for more rigidity.

With the other stainless steel plates I got on this thing (the whole machine weighs about 250 lbs) I have enough stainless plate and bar to make the frame of a mill.

Since I can use the short lead screws (the Universal ones are 12 and 14 inches) for Y and Z axes and the long ballscrew cut down for X, and since I have more than enough round and square linear rail to make the ways, I'm actually thinking I could scratch build a mill bigger than my mini mill. The only hard thing to find/get is probably a cast iron table with T-slots.
Thoughts?

For the rest of the electronics I have several spare computers, switches, wire, etc. I'm planning on a keling power supply, 3 gecko drivers, a flood cooling pump (on the cheap, like a fountain pump) and a homemade control panel. The spindle I could either buy an X2/X3 spindle or some other aftermarket one depending on my free cash level. Has anyone ever made one?

Erik

PS: I had to pass on another neat machine... a 3x3x6 foot laser engraver cabinet. Full X, Y, Z table made of 1/2" stainless with 3 steppers of about 250 oz-in size, ballscrews, hyper accurate setup. Big microstep drivers included, plus the laser, plus the power supply. He wanted $750 though... :\

[erikjgreen]

Maybe I should have put this in benchtop machines? Mods, can you move it?

Thanks,
Erik