More on High
Security Chain

What is the big deal with using a chain, as a locking device, rather than cable or armored cable?

Basically chain is hard, flexible cable is soft.  No matter what anyone tells you, no matter what size cable it is, if it is flexible then it is soft. Standard manual metal saws can cut cable very fast, however armored cable like ABUS Steel-O-Flex series 1000 or 1050 models are a good compromise.

A properly hardened* quality security chain, depending on the link gauge, will be either very difficult or impossible to cut with bolt-cutters or manual tools.

* many Made in China brands are not consistent in hardening and steel quality.

What material are security chains made of?

We have seen 1" diameter untreated chain cut like butter and we have seen 5/16" (8mm) shackles resist cutting like it was core hardened 10mm chain.  Why?  Because of the material it is made from and the hardening process.  Abus or Protector chains and locks are constructed from CRMO (chromium & molybdenum) and/or boron manganese alloy steel which, when properly hardened, becomes virtually impervious to cutting while remaining ductile.  High-end ABUS and Protector chains are put through a freeze test at -40 degrees Celsius.  Freon and CO2 only get down to about -20 C. All security chains in the lower price range (and some in higher price range too) are made in China.
While we have seen some good quality China or Taiwan made chain, by brands like Xena, Abus and Kryptonite, some of the stuff available out there is of dubious quality to say the least. Poor welding and steel quality inconsistency can easily be seen with the naked eye. High end security chains, like our UK-made Protector range, are manufactured from high quality European boron steel and specially heat treated in small batches. Every batch is sample-lab tested to ensure consistent quality (which is something most other manufacturers don't do)

Below images show the visual difference between other brands and our Protector range of high quality chains.

What is the diameter of the chain? 

When we talk about chain size we normally go metric. Our security chains range from 10mm all the way up to 19mm (3/4") thickness. Depending on what you are locking up and where you live or work, 10mm may be all you need. Weight is a serious consideration when choosing a security chain. Chain size refers to the link thickness, not the total size of the chain. You will find the total width indicated on most chains listed on our website.

10mm chains are great for low level security needs or when weight is an issue. They are not impossible to cut with bolt-cutters but way stronger than any cable lock out there. Most have a square profile.

We still carry a few 11mm Hexagonal chains but will discontinue this size in the future.

In 12mm we have a few Unique Noose chains available and ABUS Maximum Security chain in custom lengths (any length you want).

13mm is where our Protector range starts. The long link design allows for unique link through link lock-ups.

14mm Abus Maximum security chain available in custom lengths with a 6' combo special from Abus.
A few value priced lock-chain combos from Onguard or Kryptonite.

In 15mm, Kryptonite's Legend chain and lock is the only one available. Made in Taiwan with a quality above the China products but nowhere close to our U made Protector chains.

16mm Protector chains .... this is where bolt-cutters are sent packing.
Currently available up to almost 10ft length.

19mm when you want the absolute ultimate, impervious to any attack with FREE WOW factor. One look at that chain is enough to make any thief looking for an easier target.

How are chains hardened? Case or Core, what's the difference?  How is hardness measured?

Case hardening is very inexpensive and provides virtually no protection against bolt cutters. The case hardening process is usually only a few thousandths of an inch deep on cheap China products. An analogy would be a hard boiled egg.  Hard on the outside, but very soft on the inside.
High quality chains have a much deeper case.

Core hardening means all the metal is hardened to various degrees. Core hardening, often called triple heat treated, is the only way to truly defeat bolt cutters assuming the link is thick enough. Key is to harden the steel throughout without it becoming to brittle. This is where specialist heat-treatment and high grade Boron steel comes in as we see on our Protector range of chains. Getting the core and case hardness just right is very expensive which is why high security chains are expensive.

Hardness is measured in Rockwell.  Example! ABUS Magnum Lock and Chain is a minimum 65 Rockwell which is harder than some bolt-cutter jaws.
The higher the number the harder the material.  Files and hack saws are only about 58-61 Rockwell.  Ball bearings are about 63 Rockwell.  Bolt cutters are about the same hardness as a well hardened security chain so it becomes about the amount of pressure that can be applied. Obviously, given enough time and ability to make noise, a torch or cutting disc will cut any chain.

Hexagonal, Round or Square? Noose ring or continuous chain?

Theoretically it does make a difference but only up to a certain point. Hexagonal design provides a flat surface so bolt-cutter pressure is divided over a larger surface. But this will depend greatly on the size of both chain and bolt-cutter. A 14mm Square chain link is obviously going to be stronger than a 10mm Hexagonal. As of 13mm, round chain is as good as any other design.

Chain & Locking systems can be used in a variety of ways and your choice of ideal locking chain depends on your purpose. For home/garage use, go with the heaviest chain link you can possibly get and afford. Obviously, this also depends on your security risk factor. It makes very little sense to lock up a $150 bicycle with a $400 chain system.

If you need to travel and carry the chain system along, a NOOSE chain will provide a high security level while keeping weight and volume to a minimum. A conventional 6FT chain makes a complete loop with 2 ends of the chain in the lock. This gives you essentially about 3FT of length.
A noose chain can be cinched around an object on one end and locked on the other end. Making a 4FT noose chain the equivalent of 8FT conventional chain.
Our long link Protector chains have the ability to interlink trough any link in the chain. This allows you to use 2 locks (one on each end) or to link 2 chains in a figure 8 with only one lock. (see here)

Can it be cut with a bolt-cutter / cropper?

Size matters but anything can be cut with the right tools.
Our experience is this. Most chains up to 10mm, no matter how hard or what material is used, can be cut with a standard hardware store 3ft bolt cutter, IF, and this is a big if, the conditions are right.
You need to be able to put a lot of pressure on the tool and this is not always possible. 12 to 13mm chain can be cut with very large professional cutters like Irwin's 42" monster cropper but this depends on the person doing the cutting. Not many people can do it and again it is much more difficult if the chain is harder to get at. Also keep in mind that chain links need to be cut twice.
Our new 16mm and 19mm Protector chains are IMPOSSIBLE to cut with any hand operated bolt-cutter that can normally be carried around.