A plunger can for a roller assembly within a pulverizing mill has a body which contains a compression spring. A stub shaft transfers the force generated by the compression spring to the roller assembly. A bushing in cooperation with a locking guide in the fore end of the plunger can, along with the stub shaft in an aft end of the plunger can, contains the compression spring there between. The locking guide has an annular flange that fits within an annular channel within the plunger can body. A plurality of extensions spaced around an outside perimeter of the annular flange cooperates with a plurality of extensions around an inside perimeter of the plunger can body such that both sets of extensions clear each other when the locking guide is inserted into the plunger can body. When rotated, the sets of extensions are aligned with each, forming a mechanical lock.