Soviet ZGK combination lock

[@tp3521]

Great job figuring that out for us! No need to apologize for giving a thorough description of how that unique lock works!

[@m0g07]

Thanks for the video! Really awesome to see how it works, super cool and unique lock indeed :)

[@alexandermundy2403]

Thanks m0g. I had an insane idea (because it is taking so long) and I am making a clear acrylic version. BTW, got a Moneo now. It is in my future project drawer.

[@m0g07]

@@alexandermundy2403 hehe I've seen some pics of your progress in the discord! looking forward to seeing it finished! I am well familiar with the future project drawer - I have a few too many safe locks sitting in such an area myself. Hopefully I don't find more nice-looking locks before I get through a few of those!

[@Pyrolock]

Yes, an interesting lock -- seems like there is another video that shows this lock as well, perhaps that is the Trideka? Thanks for the "assembly notes" should one acquire one of these.

[@alexandermundy2403]

That video by Alexander is what got me interested in this style of lock. I have so far been unable to get my hands on a "Тридакна". "Tridacna" so I misspelled it and will correct that. kzbin.info/www/bejne/eHTVhGxrotiGaKc

[@keymad4]

love your lock content I need more please

[@MagnitkaABC]

Спасибо! Отличная работа!

[@alexandermundy2403]

Спасибо, что вдохновили меня видео о тридакне.

[@Magicspirit11]

Looks like the Russians (Sovjets) wanted to bust your balls with this one. Great video thou. Thanks for showing those mechanical marvels. As a safetech I truly appreciate it.

[@MikkoRantalainen]

Great video! As the dial ring is the way to apply tension to the core and it's only held place with a single set screw, it also prevents brute forcing the tension because once you snap that screw, opening the lock even with correct combination gets hard. Is the bearing ball for the dial bigger than the balls for the actual "sidebar alternative" so that you cannot feel the gates if you put some tension on the dial ring while entering the combination? Or is the machining good enough to now leak information directly by manipulation?

[@alexandermundy2403]

I don't think the slightly larger ball bearings would have any effect on feeling the gates. I think they were just ground to that size for better fit to reduce slop in the dial. Or perhaps just a particular machining run of the ball bearings themselves. There is only a +0.009 inch difference between the dial balls and the rest of the ball bearings. The machining tolerances are pretty slack as would be expected from a mass-produced item of that era in the USSR. I couldn't feel any difference with a gate lined up and not lined up. However, I think it might be possible to manipulate it in the same fashion as a direct entry fence lock. Either a long pointer or a digital inclinometer attached to the dial ring.

[@gss3829]

Those locks has been desgnet mainly to fit for the bomb shelters!

[@gss3829]

How can I get an instructio!? Any download links!? Have a same lock on the garadge gates strugling to oupen. I'll be grateful for help!

[@alexandermundy2403]

Do you have the combination? Without the combination you will have to disassemble the lock.

[@gss3829]

​@@alexandermundy2403 yes I do have a combination just confusing with turnig directions!

[@Magicspirit11]

Any idea how you could manipulate it?

[@alexandermundy2403]

Possibly the same as a direct entry safe lock. Measure rotational amount of dial ring with long pointer or inclinometer while manipulating. Haven't verified that though, been busy machining a clear acrylic copy of this lock so it is disassembled for measuring as I make the pieces.