Thread: How does Lapping actually work?

Lapping does two things.

• Establishes a flat profile
• Removes clogged swarf filled hone stone.

The flat profile is important when switching from hone to hone to hone.
If all hones dished at the same rate this would be almost unnecessary
but they do not wear at the same rate so lapping can help. In my limited
experience hones wear wrong. The coarse hones wear faster and
then the finer hones cannot touch the bevel at the edge. A 10k or
finer hone with a little sway back will produce a nice micro bevel.

Clogged swarf filled hone stone does not cut as fast
as fresh clean stone. A hone that is clogged can glaze over
and get slower and slower. For some barber hones and finishing
hones this is a good thing because it makes the hone cut
less i.e. finer.

I have an extra extra coarse large DMT for lapping flat. I do run a
very very worn old but smaller DMT over my fine hones to smooth
the surface of my finer hones because my big DMT is a bit rough.

I have noted groves on my Norton 8K. As the hone gathers swarf
the deep scratches are visible. As long as I can see these scratches
I consider the hone flat and just rub the swarf off with my hand. The
best Norton 8K edges I get are the third or later razors after lapping. So
yes for me crazy grinding the top of a fine hone is not totally necessary.
Especially because I can see when the hone departs from flat.

Summary:
Lap for flat
Lap to remove swarf when less aggressive tricks fail.