Combination Dial Padlock - Help needed

[mmcc]

Well, I have a practice set of about 26-27 different types of lock. I've worked my way through most of the pin-tumbler locks, handcuff, warded cabinet locks, etc. Tonight though, I have been playing with a cheap ass chinese combination dial padlock. It looks something like this:



I can't use a shim because the the shackle is secured with a square bolt that does not retract without the combination. The feedback on the dial is useless for any tactile approach, pulling the shackle tight does not work, calculating the digits does not work and there are no unique sounds that betray the code.

What options are left for non-destructive opening?

Btw, I'm quite impressed by this cheap lock...I've also encountered a cheap 6-pin tumbler lock from "Capitol" that also is putting up quite a fight.

[zeke79]

You might be able to "rap" it open. Using the kinetic energy you might be able to bounce the locking lug out of the shackle long enough to open it.

[mmcc]

I gave it a shot and it didn't work. I opened it and tried to move the bolt with a strong piece of metal and it just won't budge at all. So, attacking that area is just not viable.

Are there any other ways to find the combination?

[Squelchtone]

I gave it a shot and it didn't work. I opened it and tried to move the bolt with a strong piece of metal and it just won't budge at all. So, attacking that area is just not viable.

Are there any other ways to find the combination?

If you opened it you must have the combination already.. some locks are just not hackable int he way you're trying, no matter how much time or effort you throw into them. The manufacturers have gotten wise to the old tricks and started putting in wheels where there are false gates all around, so things like pulling on the shackle while dialing the wheel no longer works like it did 10 or 20 years ago.

If you're trying to develop a way to reliable open such locks, cut one open, study it and then devise a method. Sometimes you can look into the lock while it is open and see the wheels spinning around, if you can you can dial the lock and see when the wheels line up and then do some math and figure out the offset of what the real numbers are.

Squelchtone

[mmcc]

That's the reply I was dreading..."some locks are just not hackable".

Is this the bottom line?

This lock only cost 1 quid, so I'm a little shocked at that level of security. Btw, I do have the combination, I'm just looking for a non-destructive method of opening it.

[MrAnybody]

That's the reply I was dreading..."some locks are just not hackable".

Is this the bottom line?

This lock only cost 1 quid, so I'm a little shocked at that level of security. Btw, I do have the combination, I'm just looking for a non-destructive method of opening it.

I'd go for the cut-the-motha-open route for an autopsy just as Squelchy suggested, for the same reasons as you've given above. I think that would be "the bottom line".

I'm also surprised that it's proving to be stubborn given that it's a cheapo, but understanding the mechanics is probably the best route to go, if no one comes up with a hands-on solution. It would just plain bug me far too bad to just let it sit there in my lock box.

OK, it's a destructive, but whenever you come across another, you'll be ready for him.

Then you also have the pleasure of buying another for a buck and away you go laughin'.

Anyways, let's hope someone pops up with a solution first.

[mmcc]

I was really hoping that the combination dial would be a solved problem. As far as I can see at this point, it is a standard triple disc with a square bolt going into the shackle. It just doesn't seem to have the issues that the Master variants of these locks have.

I think the trick here is the shape of the bolt holding the shackle and the fact that it is not spring loaded. Its just a supporting bar that gets kicked out of the notch in when you clear the dial.

The plastic and construction is that cheap, that you can't really tell what is happing inside. I think the inability to pull on the shackle and feel the notches is to do with the placement of the bar that falls into the notches. I've tried getting some physical feedback when I align the first number too, but there is nothing.

I'll try to pick up another one and then I'll pull one apart.

[zeke79]

You can always brute force it. Take the dialing tolerances into account and start dialing.

[Squelchtone]

So, I bit the bullet and dismantled this thing, so here are the shots:



and the rear...



Now inside...



So, we can see why it is very robust. The discs are supported by a spring loaded central column which keeps them in place. The pulling of the shackle does not work because the edges of the notches are rounded. Difference in dialing pressure cannot be felt because the notches are hidden by a slight variation in depth (clever) at rounded edges of the notch. You cannot even feel it along the shackle because of this feature. A shim does not work because the bolt cannot physically move anywhere.

AHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!

I think that sums up my feeling here.

Anyone see a fault???

[zeepia]

Thanks for the pictures!

How well was it put together, could you insert a very thin shim between two body parts and feel the disc positions from there?

[Raymond]

A shim down the side of the shackle would allow you to put pressure against the pivot arm. This would allow some feel of the wheels against the fence as the dial is rotated. You should be able to detect at least one of the opening numbers. The other two would then be determined by trial.

[mmcc]

The locking mechanism obstructs access to the dials, the shackle comes into the right of the bolt in those pictures. So, a shim will not work.

Raymond, I will pick up another one of these locks later today. Hopefully, they are in stock. I will try your approach. As far as I can see at the minute, the rounding of the corners means that the gap cannot be felt as the bolt is raised above it by the other dials. Given the flimsy nature of the dial and the loose construction, I don't know if it is possible to feel when a single dial is no longer placing pressure on the bolt.

Anyway, I will try and get back to you.

[MrAnybody]

Raymond, I will pick up another one of these locks later today. Hopefully, they are in stock.

Where do you buy these from? Got a link?

[mmcc]

I bought them from a local pound store. They are distributed in the UK by PMS International under the brand name Secure Tech.

I have just picked up two more and I may have found an Achilles heal. The discs are mass produced, so it appears there are only a limited set of combinations. One of my new locks has the same combination as the old one.

I will try this idea with the shim soon and let everyone know if it works.

[mmcc]

Well, I tried the shim. It made no difference to the tactile feedback and the notches could not be felt. Other than the standardised combinations, I don't see a valid attack for this lock.

Anymore ideas???