John,
These they are very similar in appearance but different in function. The British Borer was used to do the same as a Fuze Gimlet, that is to reduce burning time on a fuse before it was inserted in the projectile. The Fuse Auger on the other hand, was used to change the burning time on a fuse after it was set in the projectile by removing powder from the fuse. The depth of the auger was sent with a graduated scale to accurately removed the powder.
Dan
