I'm Imperial
My plan is to use 1" ID open linear bearings on a 1" supported hardened shaft for Y; Then .5" ID closed linear bearings on .5" oil hardened drill rod for X. My Z will be .75" ID closed linear bearings on .75" hardened shaft. (weird size choices I know, but those are what were available on E-Bay) I'll build the machine out of MDF and am guessing in the neighborhood of 20 pounds of weight to move around. I'll probably get it lower than that, but am trying to be conservative in my estimate. I plan on using thrust bearings on either end of a 1/2" thick delrin block for my all thread support at my driven end and a simple bearing at the far end. For my nut I plan to use the all thread to cut threads in another block of delrin. I just found the tutorial with formulas to estimate component sizes in the FAQ and am going to put my numbers in tonight and see what comes out. I plan on cutting mostly foam, MDF, Delrin, a little light wood now and then and one small part from 6061 Aluminum. I plan on using a small end mill and going extremly slow. I will probably end up making it smaller than my dream size, but want to make it big enough to upgrade later without buying new linear bearings and shafts. To think this all started because I wanted to turn an old printer into a stencil cutter. It just got bigger and bigger
Thanks again for the quick reply. This place is great! If I could just figure out how to stop reading thread after thread until early morning.
Randall