I whipped one up yesterday. Cut both butt ends at 30 and a kerf. Can file from the end inward for right and left cutters, and think I can use more of the file than a 90 cut butt.
Kept the print on pipe up so to use it as angle reference.
Easy to cheat the angle that way. Like for used up stump chains so not to remove the heel from cutter tooth.
I did one beat 325 chain and concluded I need a new box of small files and throw away an old dozen. I might hang weight or tension on the chain slack.
I thinner kerf might be better than the carbide tipped miter saw I used. Stumps and dirty wood don't care tho.
Not my every time thing but maybe the go to for beat chains that no longer fit my grinder, I have a bunch of those.
And I know, I need a new camera.
Like I said, too simple.