Gary Stephenson wroteThe original locks were probably from something like Tann or Ratner bookroom doors
This may help.
The TANN 9 Lever Bent Case Safe Lock.
After the successful introduction of the small case KROMER 9 lever Novum lock into the Borehamwood safes with its very considerable reduction in boltwork inventories a similar exercise was proposed for Billericay.
The “9 lever bent case lock” was designed about 1975 to replace the standard 10 lever brass case lock on the Billericay safe range and it was projected to eventually replace the Novum lock at Borehamwood.
The “footprint”, bolt gauge and bolt throw agreed with that of the small case 3 & 4 wheel combination locks. It was almost 100% interchangeable and therefore gave a considerable cost saving in the number of boltwork parts required.
The final design did not agree with the original lever layout drawing given to the Billericay design office. (This was not unusual with the internal politics of that period ‑ WHS no longer controlled the drawing offices). The lever tool was rushed through and a number of Novum cases were bought from KROMER to facilitate initial production.
In order to reduce the effect of manufacturing tolerances the levers were cut in packs to the operating keys. No barrel and curtain was fitted in the original locks; it being considered that full false notching was sufficient. These were machined in at the same time as the gate, using ganged cutters. NOTE! The number 1 lift lever had its leading racking radius increased by a squeeze pressing operation and was never false notched. It has been noticed that KROMER did notch this lever, but not the first batches(?).
Due to lack of prototype testing a rash of things when wrong with the first production batch.
These early locks were “tight” in their action (a combination of thick lever material and locksmiths not face filing the levers. The sluggish action sometimes allowed the live AED to pull bolts out of the unlocked position. Originally the lanket was open to the talon ‑ which allowed a stop screw to be fitted through the rear face of the lock, as and when wanted. The factory decided that this open lanket was “useless” and re‑tooled the bolt tail to the closed lanket as seen today. Thus the stop screw had to be moved to the cap. Changing it now meant that the lock had to removed from the equipment in order to make any alteration.
Very considerable trouble was experienced when someone in main assembly decided that some peculiar oil would silence a “squeak”, but after a few weeks in service the oil thickened so much that many lockouts occurred. Oiling of lock mechanisms or keys was strictly forbidden.
The Billericay shop floor and Production had this urge to alter components usually without considering the overall design or how one modification might start a knock‑on effect. E.g. they also moved the lever pivot back a few thousands of an inch, (this was a fairly safe modification since within narrow limits no geometric conflicts occur) but they did not move the bolt stump to suit ‑ which put the talon out… Their tactic was usually to say it wouldn’t work but by doing this it did ‑ please alter the drawing. Most problems were due to incorrectly made parts anyhow, and a minor adjustment could easily have been done by the locksmith ‑ who generally was only too happy to use a file.
They insisted that the racking was weak when subjected to heavy pressure from near wrong keys ‑ and produced examples where the leading bar had bent inwards, effectively closing down the gating width to less than the bolt stump thickness. This was “cured”(??) after they were told to leave the pocket out of the lower 6 levers, i.e. to use a plain blank. The pocket was retained in the upper 3 levers since they were required to fall and hold the bolt in the withdrawn position.
As boltworks were rationalised to use this lock the need for a nozzle became apparent since some mountplates were well off the inner door face. It was needed to capture the key as it left the keyguide otherwise the key could be turned within the glass plate space. The nozzle became a standard fitting.
When the Billericay works closed this lock was transferred to KROMER and they made it for several years. Borehamwood Production Control could never get their lock stocks correct and there were many occasions when, with a lock had a nil inventory, KROMER could not be inveigled into bringing their computer programmed deliveries forward. Eventually someone decided that an alternative supplier was necessary. LOWE & FLETCHER were chosen ‑ their unit price being slightly less than the German which allegedly justified the change. But there was an enormous hidden tool charge…
All Billericay and KROMER made locks used the standard TANN detachable bit but these apparently gave L & F problems and a switch was made to the slip bit assembly (similar to the standard CHUBB “P” pattern and “RanTann”). This in turn gave trouble since, unless the slip bit itself was made to be a snug fit in the key stem, it dropped slightly out of stem after the key had rotated 180 degrees and trapped in the keyway. A simple, inadequate, barrel was added to the nozzle assembly to cure this.
More recently the slip bit was changed to the bottom insert design as used by SMP. This too gave problems: the bit falling out if improperly secured and in some instances the key missing the stop screw, but only when unlocking!
Visually the makers of the three groups of lock can be determined as follows:
TANN Always had one cap fixing screw sealed with paint.
KROMER Always a grey hammer finish on the case and a semi matt battleship grey cap.
L & F Always a passivated zinc plated case; most locks having slip bit keys.
Differs.
This 9 lever lock had a theoretical 10,077,696 differs. The differ chart had a factorial 6 series (=720) for the first 6 digits and a selection of combinations (= 53, a prime) for the top 3 levers. The factorial series was restricted to have a constant in the 6th position until all the 120 available combinations had been permutated (= 6360). The constant was then changed, and so on. This made the chart easy to produce in batches and gave 38,160 differs before the system needed altering.
Examples of the first 6 positions of the keys:
key 1 = 123456… ) first batch (First factorial = 12345)
key 2 = 123546… ) [with a constant ‘6’ in the sixth position]
key 3 = 124356… )
key 6361 = 123465… ) second batch
key 6362 = 123645… ) [with a constant ‘5’ in the sixth position]
key 6363 = 124365… ) etc.
Thus every key differed by two levers in the first 6; one high one low. The mini chart for the top 3 levers was incremented each differ so the system gave a well scrambled chart.
After 1980 WHS personally supplied Billericay with all their differ charts using a home computer to produced them.
Charts for these lock were later supplied to KROMER and later still, on request, one batch to LOWE & FLETCHER.
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