A really well-designed combination lock | Hacker News Reader

A really well-designed combination lock

scottbarstow.com

36 pointsnimz18 comments

A well-designed product is not just one that had a clever idea in the concept. To be a well-designed product, it must also be reliable, usable, and above all have great build quality.

As someone who bought one of these and threw it away in disgust after being unable to open it once I supposedly set my own combination, I'd never call it a well-designed combination lock.

As uptown says, the reviews on Amazon alone bear witness to the fact that this is a shoddily built lock which often fails one of the only tests that really matter for a lock, namely, can you open it?

I'd rename this article "A really clever idea for a combination lock (that failed in execution)."

I've had this lock for months and it's never failed me. I didn't even want it since it was more expensive than most locks but it was the only one at my gym's shop.

Until you read the reviews on Amazon:

http://www.amazon.com/Master-Lock-1500iD-Combination-Assorte...

It's a nice practical joke task to rearrange those stickers, I'm quite sure there are plenty of users who can't open the lock after that.

Personally I wouldn't ever record password, I would record the combination. Because there is that risk. I have seen way too many people to fail with simple tasks like this.

Just like changing log-in domain or putting caps lock or numlock on (laptop). So much lulz and waster effort due users who are unable to grasp what's happening.

Btw. When I was kid, there were bicycle locks using the same idea.

Yes, those 80s bicycle locks were the first thing I thought of when reading this. Really the main difference is including stickers to allow spelling a password.

It's a terrible product that rusts and jams extremely easily, requiring a saw or bolt cutters. Good design is about more than ingenuity.

Some great information on the innards of this lock can be found at http://itknowledgeexchange.techtarget.com/security-corner/ph...

Very interesting... I had seen this lock before, but I wasn't sure how secure it'd be. Playing with the simulator (http://toool.nl/images/e/e1/MhVisualizer_V2.0_p.swf), found in a link on the website bewoody provided, I'm still not sure I'd want to trust this to anything I truly value.

For example, UDL is the equivalent of LDL, and UDLR is the equivalent of LLR... but by extension it is also equivalent of LDLR. There are 5 positions for each of 4 tumblers, but not every tumbler position is valid, so the total number of combinations must be far less than 5^4.

I know that the dial combination locks have a reverse combination as well, and that the total number of tick marks is actually greater than the number of valid positions for the dial, but this whole system reminds me a bit of a game of lights out.

I had the plastic one used in an exterior location, which isn't a good idea – was always finicky and difficult. The metal one seems to be more reliable. I wouldn't trust it somewhere I cared greatly about security, but combination locks aren't generally great in those cases.

One of the difficult parts is telling anyone else how to use it. Up-down-left-left-right, but only after you pushed it in to reset it? With a standard combination lock all I have to tell someone is the combination, and one of the great parts of a combination lock is that you don't need to copy a key or anything in order to delegate opening it.

So in my opinion it's only an okay lock.

> With a standard combination lock all I have to tell someone is the combination

I don't think that's fair. The standard combination lock interface is well-known, not intuitive. "6-38-16" is brief, but it assumes the listener already knows to translate that to "turn right 360 degrees, then right 6, left 38, right 16". This lock doesn't seem any worse in that regard.

> The standard combination lock interface is well-known, not intuitive.

Indeed. Over in this part of the world, I have never actually seen one. I once looked them up on the Internet just to figure out how to use one, but had by now forgotten about the starting reset.

Those stickers look gorgeous and like they would survive a hurricane....

There's a nice PDF that discusses the mechanism

http://toool.nl/Image:The_New_Master_Lock_Combination_Padloc...

Is it still just as easy to shim as the old ones?

"now heinously ugly"

A combination lock may not be sexy, but I see it as a classic design. There is no way you can call it hideous unless you have some childhood locker trauma to work through, and/or you only date supermodels, drive expensive cars, and live in a million dollar home.

It seems like it would be easy for someone to watch you enter your combination from a distance.

Mechanism simulator: http://toool.nl/images/e/e1/MhVisualizer_V2.0_p.swf

I guess you could use the Konami Code on this one.

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