1. Bit Diam. Max Speed
3 to 9mm 24,000 RPM
10 to 35mm 18,000 RPM
38 to 50mm 16,000 RPM
56mm plus 12,000 RPM
2. Bearing care:
Ball bearings should be cleaned in solvent and dipped in light oil after use
Feeding the bit too slowly causes fiction and burning.
Blunt cutters will also cause fiction and burning.
Blunt cutters will also cause burning aggravated by a fast feed rate.