Brass Electric Motor Shaft Clamp, 3.17mm, Small Chuck Fitting for Micro Drill 1.0mm

From the shop's description

Features: Used for 3.17mm motor shaft. The meaning of 3.17 mm (0.8-1) is the motor size is 3.17mm, clamping drill of 0.8 mm to 1 mm. Concentricity adjustment method: Before the lock bit need to adjust the concentricity. Otherwise, there will be a violent vibration. Power on rotate awhile on the smooth surface of the floor or glass. Lock bit after bit concentric. Specifications : Material: Brass Color:gold(as picture show) Size: 25mm (L) x 8mm (Dia.) Diameter of back shaft (match the motor shaft): 3.17 mm Package includes: 1 x 3.17mm drill chuck