introduction of friction to plug rotation

[inverseentropy]

I've been practising with a small pile of American 1105 and 5200 locks. At first they were daunting and seemingly impossible to open, although after doing some reading I found that using very light tension works like magic. They are fun to pick because they have lots of serrated and spoorated pins and it is easy to feel what is going on inside. My cheap Brinks padlock on the other hand often gives me quite some trouble because the movement is a bit rough and it has a spring that resists plug rotation. I also have an old military American padlock that appears to be just an ordinary padlock with a few spool pins. I can only open this lock by using luck! The problem is that there is strong friction in the plug rotation (probably because it is old). When a false set happens the plug turns, but it doesn't turn back. Probably if I put a shim in to make the tension wrench a tight fit I could gently push the plug back until the false set is released, but even in that case the friction makes it hard to get any feedback to see which pins are the spools. This is in contrast to the relatively expensive (OK, slightly more expensive) American lock in which it is plain as day which pins are spools.

So, my point is that if there were a way to add friction in a controlled manner it could make a lock really hard to pick. I don't think I have ever seen this done, and I'm not really sure what sort of gunk could be used to do this without risking seizing the thing up. Ideally one would have a very high coefficient of static friction so that a whole bunch of tension is required in order to make anything happen, but then a low coefficient of dynamic friction so that when it moves it slips out of control. In this scenario picking the 1105 would require a ton of tension to overcome friction plus the tiniest bit of tension possible in order to work the pins. It would be a delicate balance. The spool pins would not give any feedback when they are caught, and in order to release them a ton of reverse tension would be needed and once the cylinder budged it would probably go too far back. Sandpaper-on-sandpaper has about the right sort of properties, but of course it wears out and leaves stuff all over. Maybe I could scrape crap out of old junk locks and use it to anti-lubricate new locks, maybe sell jars of "old crappy lock scrapings" in the store...

Another possibility would be a spring-loaded member resembling a sidebar that would lock into micro-serrations in the plug. The first serration would be centered on the "at rest" position of the plug. There would be tension needed in order to overcome this and to work with the pins. When a false set is achieved the lock passes through the second and third serrations. Careful reverse tension would bring the lock from the third serration back to the second and then back to the first. But oops! The first serration is the rest position and all the pins fall back down. What is needed is to bring the lock back to a position between the first and second serrations, but this is not easy since the sidebar will always push the plug towards the nearest serration. You need negative tension to get to the 1/2 mark, but once you cross it you need positive tension to keep it from going back to the rest position.

[femurat]

I agree with you about friction. In fact many old padlocks are a pain to pick for this reason. Maybe we just need to leave the lock resting for a few years in order to grow old like red vine

Seriously speaking: sometimes the dog spring requires heavy tension to overcame it, and then it became difficult to feel the pins feedback. Balancing the tension is different from lock to lock and requires a bit of practice. I think a strong spring is the way to go, but I'm not saying anything new. Your friction idea instead could add something new in lock design. Combining this two aspects could result in a new concept of pick proof! Keep it up.

Cheers

[EmCee]

I'm probably talking rubbish, but could you not achieve this by machining a channel (or a couple of hollows) in the wall of the housing to accept a spring loaded roller (or ball bearings) in the wall of the plug? Or vice versa of course.

If the channel/hollows were offset from the roller/ball bearings by a degree or two when in the unlocked position, then they would locate as soon as pressure was put on the tension tool. Force would then need to be applied to rotate the plug in either direction. Since the roller/ball bearings would not want to stay half-way up the slope of the channel/hollows, there would be torsion force on the plug unless the roller/bearings were either fully located in the channel/hollows or fully out of them and pressing just on the 'flat' part of the wall.

You wouldn't need friction throughout the turning circle of the plug, only in the first few critical degrees where binding pins are being felt for.

Cheers...

[nostromo]

Could be done. Good ideas. Commercial manufacturers probably don't want to spend the money for tooling though. Look how popular Kwikset is. They keep the manufacturing and distribution costs (and security features) down - down -down.

A spring loaded plug as is found on many padlocks is pretty challenging, but that's a design feature for relocking reasons, not security. Guess it's a nice accidental security feature.

[Raymond]

Somebody else offered this tip to resist bumping. On a 6-pin lock, key it to only 5 pins. In the sixth space. drill out the top chamber only to accept a ball bearing of a size that can only go about 1/3 of the diameter into the original pin hole of the plug. Increase the size and strength of the top pin. The bearing will try to keep the plug straight until turned. Overcoming this resistance would be difficult to balance between turning too hard and just enough.

[globallockytoo]

Somebody else offered this tip to resist bumping. On a 6-pin lock, key it to only 5 pins. In the sixth space. drill out the top chamber only to accept a ball bearing of a size that can only go about 1/3 of the diameter into the original pin hole of the plug. Increase the size and strength of the top pin. The bearing will try to keep the plug straight until turned. Overcoming this resistance would be difficult to balance between turning too hard and just enough.

Why bother with that cost when switching to Bilock solves all bumping and key duplication problems!

[mh]

Why bother with that cost when switching to <product name> solves all bumping and key duplication problems!

Hi,

Because this part of the forum is all about creativity and new ideas, would you please leave out statements that are simply ads for products you prefer or sell?

Thanks
mh

[globallockytoo]

Why bother with that cost when switching to <product name> solves all bumping and key duplication problems!

Hi,

Because this part of the forum is all about creativity and new ideas, would you please leave out statements that are simply ads for products you prefer or sell?

Thanks
mh

And if i had said Abloy, would your argument be the same? (i doubt it)

[jwhou]

Somebody else offered this tip to resist bumping. On a 6-pin lock, key it to only 5 pins. In the sixth space. drill out the top chamber only to accept a ball bearing of a size that can only go about 1/3 of the diameter into the original pin hole of the plug. Increase the size and strength of the top pin. The bearing will try to keep the plug straight until turned. Overcoming this resistance would be difficult to balance between turning too hard and just enough.

The more I think about this, the better I like the idea. It would not only making bumping impossible but picking would be quite difficult as well since by the time enough torque has been applied to unseat the ball bearing, the pins would bind too much. Basically the torque limiter prevents any fine grain control of torsion to the plug that's needed to pick the lock. Also, if this was the pin chamber closest to the bow, it effectively blocks the shear line from being drilled cause the ball would just spin as soon as the drill hits it. The only thing that I might want to add is to thread a set screw into the plug first so that the ball can't be picked as well.

If you really wanted to preserve the sixth pin, you could just drill into the housing and plug at an angle to line up a new bore hole and corresponding dimple in the plug, overbore the housing hole, thread in a pipe to create a single chamber bible. If you line this up with one of the existing pin chambers, it could act as a trap pin. Only thing is this would no longer provide any drilling resistance.

It would mean that it would take a fair amount of torque to operate the lock with a key and hopefully the key will be able to withstand it.

I wonder why we haven't seen torque limiters in locks before? (perhaps we have but I'm not aware of them)

[FarmerFreak]

I wonder why we haven't seen torque limiters in locks before? (perhaps we have but I'm not aware of them)

I've seen ball bearings over the sixth chamber before. In cheap knockoffs of American padlocks, and in some old locks with a Weiser keyway (could have been a real Weiser, I don't know for sure). It was always a rare find and I haven't seen one in a while.

They aren't that bad to pick though. It's all about finding the right tension, basically medium tension is now your light tension, and heavy tension is now your medium tension. I've never tried to pick gun/bump key one. ...But that has more to do with the fact that I rarely ever grab my pick gun and virtually never use a bump key.

[fjardeson]

Friction is actually implemented in the (gorgeous) mechanism of the British Ingersoll. It is a rubber O-ring that damps motion of the cylinder making it harder to get feedback from the levers. I've never seen an O-ring on a pin tumbler lock but I can see that it would definitely interfere with feedback from the pins.

And it would be a fairly cheap thing to implement, just turn a groove in the plug and stick an O-ring in there, with just enough compression to damp the rotation but not enough to wear out the O-ring.

The sidebar/detent idea is quite clever, it would really mess up the feel of a lock - especially if you used different (internal) diameters of spool / mushroom drivers. Ouch!

[Rickthepick]

Maybe we just need to leave the lock resting for a few years in order to grow old like red vine

Id buy one! A weathered lock can take a good 15 mins of freeing up before you can begin to pick it. Im sure the people that have purchased some of my used locks will be able to see that.

[Jacob Morgan]

Somebody else offered this tip to resist bumping. On a 6-pin lock, key it to only 5 pins. In the sixth space. drill out the top chamber only to accept a ball bearing of a size that can only go about 1/3 of the diameter into the original pin hole of the plug. Increase the size and strength of the top pin. The bearing will try to keep the plug straight until turned. Overcoming this resistance would be difficult to balance between turning too hard and just enough.

I know this is an old thread, but a patent for this very thing was applied for by Kwikset in 2013 (or at least several people assigned it to Kwikset, so they probably worked there).

http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN/9181728

(once there you can click on "Images" to get to the drawings)

A month or so ago (before finding this web site or being aware of what Kwikset had filed for) I had the same idea and got a ball-detent kit from Brownells (gunsmithing supply house) and drilled out the (unused) #6 top pin hole in a rim mortise cylinder a size just large enough for the ball. Then drilled and tapped about half of that hole for a #10 set screw. Dropped the ball in, put one of the detent springs behind it and put the set screw in place.

I had two identical cylinders keyed the same and the normal one I opened 3 times in about as many minutes by picking or with a lock gun (I do not have bump keys). For the other lock, the one with the detent in it, I could not open with anything other than with the key. The problem was that only about 1/3 of the ball went into the core and with a heavy spring behind it it kept the core centered. That puts the lock in two states, one where the pins go up and down freely or one to where the point that the ball / detent pressure is overcome the pins are hopelessly bound up. Maybe someone with nerves of steel could calibrate the tension just right and rotate enough without binding everything, but that sure is not me. The detent tries to pull the core back into position, it is not just some tension to overcome--the thing works against you constantly. I don't think a person could lift up the ball with a pick and hold it up while picking, but one could epoxy a bottom bin in place to deny access, or instead of using the 6th pin, one could drill in on the side of the cylinder and partway into the core from the side such that there would be no way to access the ball from the keyway at all (which is what Kwikset has in their application). The lock did have a very positive feeling action, opening it with a key was not difficult, but in closing it the core sort of snaps-to and gives a feeling of being solid. If there is anything to worry about it might be how long such a lock would last before the ball wore down the edges of the hole in the core. The beauty of the idea is that it would be a very easy thing to implement on locks at hardly any cost.

Again, Kwikset filed for a patent in 2013, but since the thread above was public knowledge before that the patent application has prior art and therefore would not likely be upheld in court. Especially if there is an actual lock out there from before that time that used the concept. I'm disappointed that Kwikset has apparently not added that simple feature to their locks, it looks like maybe they are trying to sell a "smart" lock for their bump-resistant model?

[billdeserthills]

Thank you Jacob, that was very interesting

[kwoswalt99-]

I don't think the Kwikset patent would hinder picking much. Insead, I think it would be better at reducing wear, similar to the way a side bar reduces wear.