This update is for the Y axis and Z axis extensions and the Rear mounted Y stepper.
The mods to the base and column are not critical operations at all. You just need to get some stock out of the way to allow the ballscrew to pass thru and the ballnut mounts to move farther. They don't have to be pretty and can be done with hand tools. The Y axis extension will require a longer ballscrew and 2 prints are included for where you want to mount the stepper, the front or the rear. CJA Masterworks has the prints and can machine them for you. http://shop.cjamasterworks.com/Add-On-Kits_c50.htm
At the time of writing, prices are not yet posted for the extended screws.
The bearings for the rear bearing block are the same as specifed for the front and wouls assemble the same way, ballscrew, AC bearing, shim, bearing block, shim, AC bearing, washer, (2) 3/8-24 jam nuts. I used a 16 Tooth XL pulley on the motor and a 32 Tooth XL pulley on the ballscrew for a 1:2 ratio because I had them on hand. I will finally be using (2) 25 Tooth pulleys for a 1:1 ratio because you can get them with .3125 and .375 bores to use on the motor and ballscrew without modification.
Econobelt.com part #'s
QPEXLA37025F10
QPEXLA37025F12
uses a 76 tooth XL 3/8 inch belt
For futher information follow my thread on cnczone
http://www.cnczone.com/forums/benchtop_machines/111863-hosss_g0704-102.html
and on Youtube.
http://www.youtube.com/hossmachine
And as always, contact me at hoss@g0704.com
Thanks.