This rectangular, 2″ column spacer is designed to be used in conjunction with the rectangular, rigid column bases. If you have a 4″ rigid-column base you can machine right down to the top of the mill table. However, if you have an angle table, or a rotary table mounted on your machine you may want to have the 2″ column spacer to allow for more clearance above the table while using those types of accessories. It is much easier to add the 2″ column spacer than it is to switch out your 4″ column base for the 6″ column base.
If you are looking for a riser to use on a 5000 or 5400 series mill without a rigid column base, see P/N 1300.
NOTE: The overall thickness of the spacer block is within .001″ tolerance, but it is not recommended to use more than one spacer. As more spacers are added the stack tolerance will increase and the extra spacers can affect the rigidity and integrity of the machine.