My Keller die filer has a plastic (nylon?) collar that fits on the ram that reciprocates up and down. I am not sure if its purpose it to simply keep a large washer fixed in place below the file clamp, and this washer is an attempt to keep filing from getting down to the ram and seal?

The odd thing is the plastic collar fits into the main cast iron gearbox.

Anyone have one and can straighten me out?

Thanks in advance!