I have a 16" Poulan chain saw, model 2150. I would like to sharpen it
myself. Poulan discourages this so supplies no information in the
operator's manual as to the correct file size to use. I've researched that
there are three sizes, 5/32, 3/16, 7/32. How can I find out which is the
correct file. The blade type is 91 VJP, part number 952-051211.