Thanks for the info on the P series! My apologies on not replying sooner.
Information on the S series has been EXTREMELY hard to come by on the internet. None of the old-head locksmith shops in our area that we visited had any info either, even in Worcester.
As such my wife and I began collecting keys, with an aim toward collecting the entire S series and others accidentally joining the collection as we bought up cheap lots of mixed keys on etsy and ebay.
A few months ago we ended up with 14 or 15 of the series - it turns out there are 36 keys in the S series - and spent some time with them laid out comparing them. We noticed a pattern and extrapolated it to describe the rest of the series and so far, every key’s bitting has matched exactly what we predicted.
I am sure I am using the wrong terminology but:
- there are 3 positions of the channel milled into the side of the key “flag”. Closest to shaft, centered, and closest to end.
- there are 3 positions of the notches cut into the sides of the “flag” as well, which clear the wards in the lock housing. These combine to give 9 permutations.
- the channel can be milled on the left or the right side of the “flag”. This gives 18 permutations.
- the notch/bitting in the end of the “flag” that actuates the spring loaded lever tumbler lock mechanism has two possible depths. This gives the total of 36 permutations.
The only logical differences from the P series are that there are 3 channel positions instead of only 2 and the bitting on the end has two depths instead of one. The pattern is similar otherwise.
Along the way we also ended up with most of the P series (total of 12 keys, as you showed) and discovered that M series keys are typically used for the night lock feature you described. We also deduced the patterns for the P and M series, which are obviously far simpler than the S series. So we are aiming to complete the M, P, and S series at this point. Others we may or may not collect the entire sets, I’d be fine collecting just enough examples to deduce the bitting and warding patterns and then move on to the next series.
At some point I will likely publish the pattern and dimensions/bitting depths so that others can simply buy blanks and cut their keys instead of having to search antique shops and ebay. The patterns are fairly simple… with the exception of the A series! We ended up with two A series keys from a couple of bulk key auctions and man, those are some cool, complicated keys. It appears they have 3 channel positions (plus two faces), 3 warding positions, and 3 lever tumbler lock elements each with 4 bitting depths, for a whopping 1,152 permutations! I’m pretty glad we didn’t try to start on that series, we never would have gotten anywhere.
