This nut is part of an assembly to hold the blade holder in place within the tool carriage.

It allows for accurate cutting and prevents the blade holder from moving once inserted into the tool carriage. This helps the bearings inside the blade holder spin the cutter blade without any outside vibration. To replace the entire assembly the nut (part #21575134) and the bolt (part #21815109) are required. This item is for use in the CAMM-1 GX-24 & CX24 vinyl cutter.