/diy/ - Do It Yourself

>>1446766
not gonna lie, i aint indicating shit. at least not till im more finished with this project. indicating tends to put a damper on my projects and causes me to lose all momentum. the spindle is sitting high at .0006" runnout, because i havent done a final grind on the collet bore yet . i dont have enough motors to use my grinding spindle. repeatability on the stages are less than 0.00mm, i currently have no backlash, these ballscrews have a nice preload.

>>1446767
theres a few reasons for that,
easy of use, easy as fuck to use and mount 4-6 bolts per axis
scale, at this scale, almost all linear rails are 2 rows of balls instead of 4. when you get up into rails 15mm(standard profiles) and up, they start being 4 rows, small rails (5mm,7,9,12mm) are all 2 rows making them a lot less ridged . the rails one these stages are integrated, and the balls contact the rail in a different way as well from the outside of the carriage like in the pic i posted. size for size these are the most ridged linear rails i can get before moving to crossed roller bearings
cost is the last reason, $150-200(used) from ebay for one of these units. thats basically THK ballscrew, THK rail, THK bearing blocks, motor mount and coupler. i could spend thjat much on new chinese shit or used THK, which is sooo much fucking better than my chinese shit.

pic is my harmonic gearbox for my 4th axis still in progress