Be careful when doing Through mortises, The chain can catch when you break through to the other side. When this happens the mortiser head will slam down on the depth stop, if it hits hard enough the casting may break. Just be aware and be careful when you break through.

I use chain saw bar oil on the chain, just a squirt every couple of mortises, WD40 on the posts and head pivot. Use a metal detector and you won't need a spare chain. I sharpen the chain on the machine using a chain saw file. This is a rip chain so file straight across.

Score the end lines of mortises with a chisel to avoid tear out. To keep the sides square I plunge the sides first and then clean up the middle last. The mortiser bar will flex into a void ( path of least resistance ). It will cut the best if both sides of the chain are doing an equal amount of work.