Security Flaw- Master Lock 1547DCM

[Schuyler]

craigslist!

I swear by it, man. I literally put up a post on the boston craigslist that said "Want to buy locks, keys or no keys, no problem. $1 each."

and got a half dozen responses, one of whom sold me 165 locks for 150 bucks.

I never even followed up with some of the other folks, but that guy said "yeah, 165 is the most I could come up with on such short notice. I've got plenty more if you want them"

hah, so, if he's got more DOMs and Medecos, I might have to hit him up

[pH]

I disassembled the one we cut off the locker and took a few pictures. If you want pictures of other specific parts let me know and I'll try to take some more. On the green 'spinners' the small gap (shown on the spinner on the left) is at an exact 90 degree angle to the gap on the other side, the "large gap" shown on the right.



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[Shrub]

Can i just clear somthign up in my mind before we continue,

Was the lock yours or your mates? you said it was on your mates locker i think without re-reading it,

[pH]

Can i just clear somthign up in my mind before we continue,

Was the lock yours or your mates? you said it was on your mates locker i think without re-reading it,

My apologies I don't want anyone to think I just cut it off some random person's locker! It was my friend's, all attempts to get it off failed. He told me I could have it to take it apart so we would be able to figure out how to shim or otherwise open another one in the future since a lot of people at the gym use this lock.

[Shrub]

Ah ok,

[lockedin]

ph-- great pics. Thanks man.

[Schuyler]

OK,

Now, I'm still travelling, but I'm glad I checked in. PH - is there ANY reason for the green discs to be anything but consistant in appearance? Does the gap at the bottom or the wider notches at the top actually effect the mechanics of the lock?

Because if not, I'm beginning to believe that it's actually a visual reference, either for the original assemblers or for those who masterlock figures should know how to quickly decode their locks.

And, in general, it seems shady for a lock company to want ANYONE to quickly decode their locks.

[pH]

ALright I took a few more photos showing how the lock opens and closes. Basically, it depends on the large gaps which are on the side of the green spinners facing away from the black dials with the numbers. There are a few spings within this device that I did not show, one pushes on the shackle to keep it normally closed, and I believe the other puts some force on the black plastic piece pushing it up or down.

I am actually unsure of why there are small gaps on the other side. If you can see in my first set of photos, the small bumps on the black dials fit into all the ridges on the green spinners, this is what makes them spin together. But why the small gaps? I don't have instructions for this lock, but I assume you change the combination by spinning the dials while holding the lock open? Perhaps there was just too much friction as you turn the dials doing this if every bump on the dial fit into a ridge in the spinner, so they removed one ridge to reduce friction?





PS. please excuse the crappy looking arrows and text but I think it makes the points clear!

[lockedin]

OK,

Now, I'm still travelling, but I'm glad I checked in. PH - is there ANY reason for the green discs to be anything but consistant in appearance? Does the gap at the bottom or the wider notches at the top actually effect the mechanics of the lock?

Because if not, I'm beginning to believe that it's actually a visual reference, either for the original assemblers or for those who masterlock figures should know how to quickly decode their locks.

And, in general, it seems shady for a lock company to want ANYONE to quickly decode their locks.

You're right. After looking at ph's most recent picture, they seem to serve no structural purpose. Another ridiculous oversight by Master Lock, even if these are low-security locks. It wouldn't have cost much more to make it harder to see these indicatory features.

[plot]

i've noticed this, or at least, a very similar flaw on alot of cheapy masterlocks like this. normally there's a flat edge and when you can see all the flat edges on all the dials... pop goes the lock

[VashTSPD]

great pics ph, they really helped.

[russianESI101]

i noticed the same thing with the blue brinks combo locks i cant get a pic up but u prob know what im talking about, well if you look at the right of the dials on the blue brinks lock you'll see a little white knob that has a flat spot you want to get the four numbers turned so you see the four white flat spots then add 5 numbers to each by spinning the dail a bit so if the flat side is on a 4 its gonna be a 9 if its a 7 its gonna be a 2

[Texmexgod4001]

Thanks for the info on this lock.. so many years later of the green gap. Updating the blurry pic for anyone...


Edited by GWiens2001 to imbed picture instead of link

[GWiens2001]

Thank you for the updated picture. Not blurry at all!

Gordon