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Locksmith Blog | Locksmiths Blog | Blog
Tuesday, 24 January 2017
Inside A Bramah MD27 | Locksmith Blog
Topic: General Chatter

bramah MD27 Lockbramah mortice lock

The Bramah MD27 was the first deadlock in the UK to be awarded a BS3621 rating back in 1963. A good 54 years on and this lock is still manufactured and considered one of the most secure mortice locks on the market, particularly against picking due to it's unique design, similar to that of a tubular lock but with sprung wafers instead of pins.

Bramah breakdownBramah lock core

This week I managed to get my hands on an old stock Bramah MD27 from a good locksmith friend, so thought I would do a simple breakdown so you can see what is inside. I know it's one I've always been curious about.

Firstly a breakdown of the lockcase itself. There is a flat coverplate on each side of the lock and a removable front faceplate. If you ever dismantle on of these you should probably leave the faceplate in place as the lock will eject it's bolt as soon as the key is turned, the faceplate effectively holds the bolt in once thrown.

You will notice that the keyway on the reverse side is upside down as one operates the bolt from above and the other from below. Each lock core is surrounded by a steel bushing with a cut out machined to allow the bolt roller (rear of the bolt) a pathway upon turning the key.

bramah keybramah lock breakdown of the core

I was reluctant to disassemble the inner core at first since I'd never seen one but soon sussed out how it worked. The machined brass plug has a groove around its circumferance with a circlip like steel plate in place. This is in fact the gates for the wafers to align with, allowing the brass plug to turn through it. Inserting the key and aligning all gates allowed the two halves to slide from the plug.

Each wafer is in fact a folded section of sprung steel with a one false gate and one true gate. The keen eyed lock enthusiasts will notice that all of the false gates appear to be below the true gate leaving it potentially vulnerable to opening. Can you guess how? That is a test for another day.
Bramah lock waferInside a Bramah Lock Core


Posted by Rick the Pick at 1:11 PM GMT
Updated: Wednesday, 15 February 2017 12:47 PM GMT
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