Hi Red.
Would any diamond sharpener do the job (dc3 or 4 type) ar does it need to be a diamond file. I've had a GB mini for a few years now, and I've bashed the life out of it. So far, I've not had any problems tackling jobs most may consider "too big" for the mini. I do, however, have a small dent just behind the cutting edge (no idea how I dented it there) and it dosen't appear to interfere with the cutting, so I'm leaving it alone, but ultimately, as the axe get sharpened, it will some day go into the cutting edge and i'll need to file it out.