FAB Variant

=FAB Variant=

FAB Variant is the best FAB has ever made. It belonged to a resistance class 4, which is the highest resistance class FAB offers. It was built using the ASSA Abloy patents, clearly showing relation to ASSA Twin Combi, although it is not a simple copy of it. Unfortunately it was not very successful commercially - it was quite expensive and users had problems with security fittings that weren't designed for the protruding core front. Also supporting it was a big hassle for locksmiths - keys were cut on expensive CNC machine, each cut had to be measured using a special device and every deviation had to be logged. Blanks were very closely watched and botched keys had to be sent to factory for destruction.

Description
The lock contains six pin stacks, all containing the ASSA barrel spool drivers. All chambers are overmilled, although there seems to be some variation in the design (cores with countermilling were spotted and some also had a nuta).

There are additional five chambers for the fingerpins, than control the sidebar. These fingerpins need to be both lifted to a correct height and also rotated to one of the three directions. The fingerpins are serrated to make the rotation harder. Unlike the Twin Combi, the sidebar has a bit more rounded sections where it interacts with the fingerpins, which makes the picking feedback much subtler compared to both Twin Combi and the ZI SK6 Sperrwelle Extracode. Also the sidebar faces are serrated unlike the others, presumably to make setting the pin height more problematic.

The profile used is quite paracentric, which adds to the protection against lockpicking. There is also considerable amount of anti-drill protection, guarding both the main pinstack and the fingerpins.

The key blanks were restricted and quite closely guarded; a key could be cut or copied only when locksmith was presented with a security card.

Dissassembly instructions
To disassemble a cylinder, it is best to remove the core with a key inside to hold the fingerpins inside. Before pulling the core out, always make sure the driver pins won't enter the fingerpin chambers - that means avoiding core rotation around the 4'o clock position.

Vulnerabilities
The FAB Variant is vulnerable to one or more of the following:


 * Lockpicking
 * Decoding
 * Key bumping - provided the fingerpins are set correctly.
 * Impressioning