Bearing carriers for my Sieg X1 micro milling machine.

The first image shows one of the carriers next to one of the original retainers.

After squaring up a couple of 1″x1.5″x3″ aluminum blocks, I indexed the part and center drilled, then drilled a 31/64″ hole (with my new Llambrich high precision chuck!). Reamed it to .500″ (had to use the ER32 collet chuck because I don’t have enough z-axis to fit the reamer in the drill chuck and still clear the part). In case indexing the part with the left side of the stationary jaw wasn’t accurate enough, this would allow me to use a gage pin in my collet chuck to precisely align the part once the first bearing hole had been bored to size (22mm, 0.866″, to a depth of 0.273″), and the part flipped over. In the end that wasn’t necessary, but it’s always good to think ahead and eliminate possible disasters.

Center drilled then drilled two 1/4″ clearance holes for the M6 mounting bolts, then milled away some excess material with a 3/4″ 2-flute HSS-Co8 endmill. (Many of my endmills are cobalt, but none are carbide.)

The final shots show the original and the new retainer/carrier installed on the machine, one on the Y axis, the other on the X axis. Each carrier contains two 608ZZ ball bearings (8mmx22mmx7mm), one on the front side and one on the back side. Labels have subsequently been printed for the pointer and distance per division.