Just condensing what a joint effort between Mikael, me and the Town Museum of Esklistuna has come up with:
There were three different lettering systems: MK, BK and RK, as well as Heljestrands with no letters. The 'K' designation is swedish for Quality - 'kvalitet' and the 'MK's were the highest quality, but we have not been able to find out what the M, B and R stand for.
MK, BK and RK were - apparently - different grinds. MK = Full Hollow, BK = One-quarter Hollow and RK = Half Hollow. BK and MK appeared in 1935, it seems, and RK came 1944. From 1952 It seems that MK (with three crowns inbetween) was Heljestrands only highest quality, with the
numbers 29-33. I say 'apparently' because I have seen a table collated by a member of this forum - 'bassguy' which seems to include a wedge, full hollow and hollow within the MK designation.
There were razors produced especially for France, but it seems that 'MK' has nothing to do with the sole french distributor Maison Kindal (House of Kindal) or Magnus Kindal, the proprietor. Below is a postcard from 1905 saying that M Kindal had the 'monopoly' (sole agency) for C V Heljestrand in France:
http://img.photobucket.com/albums/v2...s/087/Mk-1.jpg
Magnus Kindal, btw, ran a family business in the town of Eskilstuna before setting-up shop in France.
Three models made for the french market were with white celluloid scales, all 9/16: Royal Kindal full hollow, Le Prince half hollow and Le Duc one-quarter hollow.
As far as the numbering goes, according to mparker in the 30 series the last digit would seem to indicate the width of the blade: 30 = 4/8, 31 = 5/8, 32 = 6/8 but I have not been able to confirm this - we would have to compare pristine examples as hone wear can be misleading and I have a suspicion that a metric rather than an imperial system was used.
Anyway, that's all the three of us have been able to come up, some of it intriguing, some of it conflicting, and the main part of the work has been done by Mikael and the Museum.
Regards,
Neil