I posted before i saw your other post
If it is ” old and brittle” it would be best to do it with a mini saw and file.
If the saw dr. used a machine to do the
Work it is possable the machine was rough on the old saw. but we dont know that. A gentle filing job by hand should bring the saw back to new As you file You can feel If it has hard and soft spots In it. Paul has good videos on this and it is dead simple Hey i could do it.