Skate-board bearings:
standard "608" size, with a bore of 8 mm, an outer diameter of 22 mm, and a width of 7 mm.
later,
Dean P.
Not a bearing expert but will a skate board bearing stand 8 to 10K rpm? The above size bearing from McMaster-Carr costs $12.33 and is rated at 34,000 RPM
P/N 6153K51
Ball Bearing Style , Double Shielded
Ball Bearing Type , General Purpose
For Shaft Diameter 8 mm
Outside Diameter 22 mm
Width 7 mm
ABEC Precision Bearing Rating, ABEC-1
ABEC-1 Precision Rating, Regular
Bearing Trade Number, 608
Dynamic Radial Load Capacity, 740 lbs.
Maximum rpm, 34,000
Bearing Material Stainless Steel
Stainless Steel Material Type Type 440 Stainless Steel
Shield Material Steel
http://www.mcmaster.com/#ball-and-roller-bearings/=dzk4d6