Sunday 1 March 2020

More Brass Beauty

B-Lock II
After last week's fabulous luck with a lock, I decided to move to the other chunk of brass in my collection that has been awaiting an attempt. As I have said before, I am rubbish at solving puzzle locks despite having several Popplocks, all of Shane's Haleslocks and a couple of other of the Feldman family locks. I had absolutely loved the first lock in my collection, the amazing (essential purchase) Danlock which is available now from Dan's son Boaz Feldman and at the Paris IPP had been completely stupefied by the workmanship that had gone into the design and manufacture of the B-Lock version I (also available from Boaz). Thus, when the B-Lock II was released, I absolutely had to contact Boaz to ask about getting a copy for my own collection and to be able to write about. He put me on a waiting list and in November had completed a bunch and sold one to me. I duly admired it (especially the very nice laser inscription on the front and matching cloth bag), dutifully tried to open it as normal with the key (failing, of course!) and then tucked it away until I had some time to properly play.

The lock sat next to the Titan lock (discussed last week) and was looked at intermittently every month or so in the hope that something like an idea would spring out at me. The funny thing is that the same thing was tried every time and each time I got nowhere. Remembering the very nice trick in version 1 I had a REALLY close look at the lock but, of course, Boaz would never do the same trick twice.

Having been triumphant with the Titan, I set this as my target for the following week and took it to work. On Tuesday, after a very nice successful Abdominal Aortic Aneurysm repair, I had a little time in the coffee room for a break and the lock came out, much to the amusement of a few nurses, ODPs and consultant colleagues who were also there.

The puzzle is a standard Israeli Nabob padlock and I could see no helpful signs of tampering apart from places where access to the locking pins had been drilled and then refilled. Apart from this and some wiggle/play of the shackle, it looked like a normal lock. The fact that the pins have been drilled always makes me wonder whether unusual things can be done with the key and I tried a "thing" or two. Nope - that didn't work but it did provide a teeny tiny Aha! moment. That's interesting even if it didn't unlock it. What if I do this? AHA! again.

Gotcha! That's really quite clever.
The onlookers were quite surprised when I managed to open this new puzzle in about 3-4 minutes and several of them wanted to have a try. I kept it a few extra minutes to make sure that I really had done the opening by design rather than luck and could confirm the mechanism. I duly handed it over and several people took it in turns to solve it. Several colleagues managed it in about 10 minutes apart from one surgeon who decided it was beyond him. It was delightful to see the satisfaction on their faces when they got it.

This puzzle is available now for about £50 and, whilst expensive, is a beautifully made puzzle which clearly had a lot of work put into the manufacture. If you can manage it, I would definitely suggest you buy all 3 - they are a really good start to a puzzle lock collection.

The Monkey's Nuts
At the last Midlands Puzzle Party, I picked up a copy of The Monkey's Nuts. It's not really a puzzle apart from trying to work out how such a strange thing can happen - The normal way a nut and bolt works is "Righty-tighty - lefty-loosey". With this beautifully made and rather large (74mm x 22mm) and heavy (1lb/454g) object, turning the nuts "righty" leaves one coming off (loosening) and the other moving on (tightening) - WTF?

I had seen this made in plastic and given away at an IPP by Scott Eliott. I thought I understood how it worked and squinting at the object in the right light gives a hint (you might be able to see it in the photo above). I showed this to a few orthopaedic surgeons who tend to really appreciate fine engineering and completely failed to explain to them how it worked. A bit of Googling about found me a wonderful description of what is going on - you can download an interesting PDF showing the trick here. It really is a marvellous idea and well worth buying a copy for yourself.


  1. Caution: the PDF you linked to describes the MK3 trick bolt, a totally different mechanism. It works completely differently, although it achieves the same result: nuts that go different ways on the same thread.

    The Monkey's Nuts was adapted from the MK2 trick bolt, which was used in the plastic Its' Nuts puzzles. Brass Monkeys meticulously built custom tooling and devised additional refinements to make it practical to machine it from solid brass, making their bolt vastly superior to the original plastic ones.

    Here's a linke to a video on Greg's Channel that really *does* explain the MK2 mechanism.

    1. Wow! Thanks for that useful information Scott. Very helpful. I did not know that there were two different mechanisms.

    2. Bookmarked to my Mathematics folder. Many thanks. -Tyler.