Benchtop CNC Milling Machine (on hold)

[Brian_H]

The potentiality of a Spokane hackerspace has motivated me to continue my long lost benchtop cnc milling machine project.

The base mill is to be a Grizzly G0463 Benchtop Milling Machine:





The machine is fairly rigid for a benchtop mill and among the cheaper mills on the market. It weighs 400 lbs. The key to using small mills like this, whether manually or with cnc, is to know how to work within their limitations. This means using smaller diameter cutters and shallower depths of cut in harder materials. I expect It should be able to cut mild steel at typical feeds and speeds with a 1/4" end mill. In aluminum it will probably be ok with a 3/8" end mill and good removal rates. A friend of mine had this mill in stock configuration in his garage and we used to use 3/4" end mills in aluminum without it bogging down too much but this was pushing the limits.

Unfortunately the mill is four or five hundred dollars more expensive than it was in '08, however back then I was washing dishes part time while going to college for machining, so it is now more affordable to me.

The parts I already have are 3 gecko drivers and three stepper motors:



The X and Y steppers are 425 oz-in, and the Z axis stepper is 780 oz-in. These steppers should be plenty powerful for this machine, I believe. To complete the electronics portion of the project I will need to pick up a power supply and build an enclosure for the drivers.

There is a company called CNC Fusion who makes a complete CNC conversion kit with ballscrews for this mill. It is a bit expensive at a grand but will really simplify the complexity of this project. This is their deluxe ballscrew kit:



So the total cost of the essential remaining components will be somewhere around $2600. Non essentials like a flood or mist coolant system will add some cost. Also a 4" vise will be necessary which Grizzly sells for $130. I will need to build a heavy duty bench. Overall this conversion should run considerably cheaper than comparative ready made cnc benchtop mills, which typically sticker at about $5000.