* All ER collets are hardened and pricision ground for accuracy
* These collest are for through hole coolant and normally used on CNC machines
* Sealed ER Collets for coolant through applications do not have a collapse range, and must be used at exact size
* The radius of the collet must exactly match the radius of the cutting tool shank in order to maintain a complete seal
* If companies claim that they have sealed collets with a collapse range please keep in mind that if the radius does not match exactly coolant canals will be created by the mismatched radius of an improperly sized collet.
* ER Collets must be tightened correctly
* Many machinists have been trained that nothing is ever too tight
* This is particularly not true with collets and collet chucks. * Overtightening a collet chuck will distort the collet and actually diminish the holding strength and accuracy. * Maximum tightening torque for ER Systems is as follows:
RER 11 20 Max. Tightening Torque (ft. lbs.) ER 25 70
EER 16 40 ER 32 80
RER 20 60 ER 40 90