Axe Restoration Project: Part 4, Surface Treatment
In our last installment we had just finished cleaning 3 different axe heads in vinegar and had assessed their individual pros and cons. Of that group of 3 we decided to move forward with the Jersey head. This head was in need of a very aggressive surface treatment in order to remove pitting in the steel as a result of rust. We’ll basically be removing a layer of steel from the entire head and exposing clean new steel beneath.
We begin by sanding down the entire head using a disc sander and 100 grit sandpaper discs. This is a relatively laborious task as a good portion of the head needed the removal of up to a millimeter of steel. Fig. a shows the the head about a quarter of the way through the first sanding process. It should be noted that we find sanding preferable to grinding. Grinding wheels tend to remove too much material too quickly. They also heat up faster and hotter than sanding discs and belt sanders. This excessive heat can damage the temper of the steel, especially where the steel is thin at the bit edge. In fig. b the head has been completely sanded using 100 grit. From there the sanding grits get progressively finer, from 100 to 120 to 200. After 200 we switch to hand-sanding using 220 grit, then 320, then 400, and finally steel wool. Fig c. shows progress after hand sanding to 320 grit. As I said before this is a rather aggressive and time-intensive treatment, but the results are worth it. It’s possible to continue sanding and polishing until the steel shines like a mirror, although we think this is a bit excessive. You’ll notice in fig. c that the edge of the bit has been left unsanded and some pitting is still visible. This is because in this particular case the bit does not need any reshaping, just a good sharpening, and we prefer to tackle that job with our sharpening tools. In the case of badly misshapen bits it would make sense to use a sander to reshape the bit edge. In extreme cases a grinder might be used but only slowly, carefully, and with a frequent dip in a pail of water to keep the edge cool.