I got to the last part of the assembly of unit no2 and whilst putting on
the top a dowel broke through. It pushed a big 'scab' of sawdust wood out.
I tried to stick it back with super glue but no good....it is raised
slightly, although I put a precision flat surface on it weighed it down
with a microwave transformer. It looks like the dowel hole had been
drilled very close to the surface and the force offered by the mating hole
just pushed it through.