For optimum grinding performance and operator safety, care must be taken to select a grinding quill with the shortest possible length and the largest practical diameter. Minimum quill length should be approximately equal to the length of the bore to be ground, this allows coolant and grinding swarf to exit freely from the workpiece, but consideration must also be given to wheel thickness, fixture diameter, coolant flow, and grinding wheel wear. A length to diameter ratio of 4 to 1 is generally recommended for steel Straight Shank quills. Higher ratios may be considered but these require special care and lower than usual wheel speed.
Wheel locking width must be known to select a wheelscrew that will pilot the entire length of the wheel ID and engage the quill bore to a minimum depth equal to the wheelscrew diameter. To avoid confusion and help visualize where wheel-locking width should be determined we have pictured several grinding wheel types and indicated with arrows the point where wheel-locking width should be measured.
