Hello all, this is my first post on the forum but I've read a lot of threads here.

The machine I am building has a work area of 300mm x 300mm x 200mm and is designed to cut aluminum with ease and steel with care. It is made from laser cut 3/4" 6061 aluminum plate, and then drilled with my chopped down drill press and tapped for rails and other parts.. 180 watt belt driven (3:1 or 2:1, I forgot) servos on all axes, and I'm using a 9 axis planet CNC board to drive everything..

The spindle is a BT30 assembly, that will be belt driven with a timing belt by a 2500rpm 1.5kw servo. I do not yet know what speed I want to gear it for. I'm currently thinking somewhere around 4500 rpm top speed but I don't know for sure. I don't really want to deal with the super high speed low torque spindles many homemade machines have to deal with, and I do want to tap with this machine so I need to balance the top speed with torque. Any suggestions on the drive ratio and what belt series I should use for this are welcome.

I am building this on a $3000 budget, and the machine should be only 24" wide. Because of budget limitations I'm not purchasing any custom machined parts, and just getting the big aluminum pieces from OSHcut and using the laser and brake at work to make smaller sheet metal components such as the enclosure and motor mount. I am also using SBR20 rails instead of profile rails partly because of cost, but mostly because the mounting height matches exactly to the 20mm ballscrews. That particular linear bearings do have adjustment screws to clamp the bearing in the housing to eliminate backlash, so I think adjusting that properly will make a big difference. Also, the bearings are always very close to the tool end regardless of where the table is in its travel, so the forces seen by each bearing will always be less than the cutting force.

I have chosen to make a fixed gantry machine with a rising table, because in the case of power loss the table will gently settle to the bottom, as opposed to the spindle falling into the work. The Z and Y axes are joined by a precision ground cast iron block intended for measurement fixtures, which are readily available on ebay.

Due to Fedex problems I am still missing many plates, so the mockup is very incomplete.