PDQ makes many special master holders. Use a special PDQ holder in your machine with a non-standard spindle taper. This allows the use of standard off the shelf adapters and eliminates the need for costly special tool holders. Add quick tool changing to your high production machinery by using special PDQ master holders. Have a machine with a worn and oversize spindle taper? PDQ can make a special master holder with an oversized standard taper to save that machine.