Call me a cheap skate, but.....

I have a good quality Maun rotary hole punch that I've flogged to death and ask, is there a way of resharpening the punches.

It does not appear that the punches unscrew, there are no flats around the base of each punch. If they were removable, the job would be easy, however it looks like I'll have to sharpen them up insitu.

Any ideas on how I might do this.

One thought I had was to try and find a small dia grind stone that had a bevelled recess in the end of it. Probably nothing available.

I can buy a new one for about $35, just don't like chucking out good old fashioned tools.

Ken