Drill Bit Grinding Machine : 1.easy operate, accurate and fast. 2.With diamond grinding wheel 3.CE Portable Drill Bit Grinder :Portable idiot drill ... quality precision and prolong the service life of the drill bit. More products' information please browse our website. Technical parameters: ... Φ16, Φ17, Φ18, Φ19, Φ20, Φ21, Φ22, Φ23, Φ24, Φ25, Φ26 Apolegamic collets: Φ8, Φ9, Φ10, Φ11, Φ12, Φ27, Φ28, Φ29 ...