Locks and chains resistant to grinders

[somenewguy]

Hi folks;

I assume most attacks on padlocks/chains (for example, bikes locked up outdoors) would be with bolt cutters and similar brute force methods (prying, etc). However, I am wondering about resistance to angle grinders.

I assume 'shrouded' or disk type locks (or special hasp designs) prove to be relatively resistant to a grinder. Are there any materials for shackles and particularly chain links that make for reasonable resistance to a grinder?

[zeke79]

The S&G 833 locks have ceramic inserts to help with this. Long story short though is a grinder will chew up just about anything you put in front of it.

Hasp design, shrouds, etc make little difference.

[Pickmequick]

What is it you are trying to secure exactly and where?

If it is a bike in the middle of a busy town centre then it is unlikely someone would try and use an angle grinder due to the obvious noise.

If it's somewhere secluded and they have time to work on it, there isn't anything you can do to stop the thieves unfortunately

[ARF-GEF]

There is not really too effective defence against angel grinders, if they have the time to work for a while unnoticed they will cut trhough any padlock.
But it's noisy and attention-grabbing.
As for resistance, shrouded steel padlocks are shrouded for this reason mostly, and the thicker the more resistant. Immune? No option that I know of.
Hockey puck type padlocks like american 2000 are pretty resistant to angle grinders as well.

With chains the same: thick high security chains. I don't really know any specific brands or any specific attribution to look for. Hopefully other will chime in as well

[Dogrocket]

They use ball bearings in safes to frustrate drilling - it might be possible to do something similar with a padlock hasp by using thin tubes or washers (they should spin, making it harder for the grinder to find purchase).

Any locks do something similar, or are the countermeasures focused on thicker hasps and heavier shrouds?

[ARF-GEF]

If the ball is too smal it will just be cut through. If it's too big not much material is left. But that is a promising idea.

[zeke79]

The problem with tubes or washers is the fact that while they might spin one way, simply rotating the grinder 90 degrees (instead of cutting this way --- you would cut this way |) will allow you cut the the tube or washers off and then resume cutting the hasp.

[Altashot]

I don't know of any lock or chain that can resist attacks from a Zip disc.
Some materials like carbides, are extremely hard to grind, but will shatter if struck with a hammer.
There are no materials that will be "everything proof". As far as I'm concerned, locks are already made from the best combination of metals to server their intended purposes.
The puck lock with it's proper hasp is probably the best against grinding due to it's bulk. It'd be the most time consuming effort. Time is a thieve's enemy, but if given enough time, and enough Zip Cut discs, a die grinder or angle grinder will cut just about anything.

http://i1155.photobucket.com/albums/p54 ... 97d21f.jpg

M.

[spoonzor]

If it is a bike in the middle of a busy town centre then it is unlikely someone would try and use an angle grinder due to the obvious noise.

I have to disagree. I actually used an angle grinder (many years ago) right in the middle of town, busy area next to train station, many shops and many shoppers, to cut a lock on a scooter (my friend lost his key and I was not into lock picking at that time). Some people stared at us, but as soon as we looked back at them and asked them "what?!" they quickly move on. Took just seconds to grind of the lock and drive away. Used the electricity of a nearby shop, they had an outlet on the outside of the building intended for some kind of vending machine.

[Achyfellow]

From my experience, the best bike anti-theft system is to park it near a nicer looking bike with a crappy lock or incorrectly locked.

[Pickmequick]

If it is a bike in the middle of a busy town centre then it is unlikely someone would try and use an angle grinder due to the obvious noise.

I have to disagree. I actually used an angle grinder (many years ago) right in the middle of town, busy area next to train station, many shops and many shoppers, to cut a lock on a scooter (my friend lost his key and I was not into lock picking at that time). Some people stared at us, but as soon as we looked back at them and asked them "what?!" they quickly move on. Took just seconds to grind of the lock and drive away. Used the electricity of a nearby shop, they had an outlet on the outside of the building intended for some kind of vending machine.

I did say unlikely.

There is always 1!

[Dogrocket]

The problem with tubes or washers is the fact that while they might spin one way, simply rotating the grinder 90 degrees (instead of cutting this way --- you would cut this way |) will allow you cut the the tube or washers off and then resume cutting the hasp.

Hrm. Foiled by physics.

My only other suggestion would be some type of rubberized coating designed to foul grinder blades, but anything soft enough to gum up the blade would probably scrape off with a knife relatively easily.

[ARF-GEF]

Getting back to the practical side:
I think these disputes often miss the point with physical security and especially bike security.
If they have time and the tools, with a bit of expertise and are willing to make an effort they cut through any lock ever made, and any chain ever made.
People can get in very very serious safes if they have all 4 of that.

As many people here pointed out, the question: what to do to make it impossible to steal doesn't really makes too much sense.
The aim is to make it harder and more time consuming to breach.
A good tough steel padlock and a thick quality chain is all the reasonable precautions I find sensible to do on the lock part. Raised shackle is better than non raised. Bigger padlock, bigger chain is often better.
Frankly I find that a good chain good, high quality padlock combo is good enough in most cases, and when it isn't, a bit better padlock wouldn't have helped either.

Don't sweat it too much, don't get a bike you cannot afford to loose and the best but hardest way to secure it: don't leave a bike alone which you cannot bear to loose.

[YouLuckyFox]

Well put, AG; I agree entirely. Another point that is not often considered is that even with a big lock with a hardened 18mm shackle, most bike racks and street signs that you would lock your bike to have less overall thickness than the lock itself (most bike racks and street signs are made from thin metal or hollow metal material. Even if the perfect lock existed--that no tool could force or break--a thief could just cut the anchor that the lock is attached to, sometimes with greater ease than with cutting the lock. Then again, if a thief vandalizes a street sign or bike rack, they'd have the bike owner AND the municipality hunting after them. I agree that doing what it takes to make the marginal cost of stealing the bike greater than the marginal benefit of stealing the bike will keep the bike from being stolen.

[HerrMannelig]

Eventually, an angle grinder will get through anything.

However, a chain is superior to u-locks, because it is much harder to keep still while cutting. So, if one is attempting to lengthen the time of angle grinding, a thick u-lock which requires it to be cut twice (like the Kryptonite New York Fahgettaboudit U-Lock) or a thick chain of suitably hardened steel with a good lock would probably be the best.

Unless the bike is very valuable, I doubt a thief would want to invest that kind of time into cutting the lock, even if there is enough privacy and time available, when there are other bikes around.