Some years back I queried Tom Palmer about Pete's [de facto] grading by line, using wood quality as the metric:
This was his response:
-------------------
> >
> > Thank you for your reply of 5th February.
> >
> > By way of background, we have hundreds of different pipe shapes and
> > from say 100 pieces of shapes, say 03, 3-5 pieces would be deemed
> > "fill free". These special pieces would then be finished with the
> > following series :-
> >
> > Straight Grains
> > Supremes - Silver and Gold Mounted
> >
> > In addition the following series could have small root marks but no
> > putty, namely :-
> >
> > De Luxe System
> > De Luxe Classic
> > Army Spigot
> > Celtic Natural
> > Rosslare Natural
> > Grafton
> > Hinged Lip Cap Natural
> > Silver Caps
> >
> > I trust the above information is of some help and wish you many
> > hours of smoking pleasure.
> >
> > Kind regards
> >
> > Tom Palmer
> > Peterson of Dublin
> > Peterson House
> > Sallynoggin
> > Co. Dublin
> > IRELAND