Measuring chain and how to do it correctly
Often we get calls asking for a certain sized chain then when we ask what the applications is we find the required chain is being called the wrong size due to the way an existing it has been measured, hence why we always ask what are you using it for, it's a good double check.
Generally getting down to parts of a millimetre or 10th of an inch isn't required but in the odd area it is. Generally when we need very accurate measurements it is due to matching to a specific machine or in most cases to a anchor winches gypsy. The 'gypsy' being the sprocket that grabs the chain links. Like most sprockets they are made to accept one or a small range of chains within specific measurement requirements. Use chains outside the size range and it general leads to tears and a decreased bank account, but it can also lead to things exploding and potentially bodily harm, sure that would be unusual but it is a possibility and it has happened.
If I don't need to be too specific what should I measure?
If you are saying hanging a Love Swing (yes many do), Chandelier or want some for across a gate, then all you really need to know if the wire size. From that we can often offer a range around that size to get the best size, strength, value or combination of for your requirements.
So if I do need to get very specific what is the best way to measure chain?
One is to use calliper or verniers, they are far more accurate then eyeballs, even very good eyeballs.
In case of regional terminology differences I mean these things.
Now what measurements are we looking for?
We are looking for the 'wire size', the P or pitch as some call it (a little incorrectly but that happens) and while there we'll also grab a width. Often the width isn't that important but sometimes it can be so go for all 3 and you are prepared just in case.
The Wire size -
With your verniers first measure the 'wire size', that is the size of the wire that was bent to make into the links. It is best to measure a few links just in case you grab a bum one, unlikely but possible. Select a few at random and not next to each other. Measure away from the weld, the weld zone can be both bigger and smaller than the wire size depending on exactly what machinery it was made on. This is what you want to measure -
The P or Pitch -
This, like the wire size, is an important one when talking matching gypsies, sprockets and things like that. There are some chains that vary 0.3mm per link and that can be the difference between working well and working but doing damage leading to short term life spans for the chain and the gear it;s on. So the better you get this the better you'll be longer term.
We want the internal length of each link. Again measure a few randomly selected links to make sure you don't grab a random rouge one.
The 'pitch' is technically a measurement between multiple links but you can measure as described and you'll get the same number.
The Width -
Usually not important but while your there grab it just in case. Note – do not measure the weld zone, it will lead to quirky numbers that no one wants or needs.
Things to note -
Watch for links with obvious wear, they will give you rouge measurements. If you have wear measure a few and tell us what you get, we'll them take an educated guess.
Watch for crusts (build ups of salt and other assorted crap) Scrap it off and measure the steel under it.
Stretch, treat that like wear.
Coatings, some can be thick or have a area of build up. Treat that like crusts or hunt for a spot where the coatings are thinnest.
As always if you have any questions (or spelling corrections) feel free to ask us, we don't mind at all.
And as usual this article is written slightly generically and has been simplified so it doesn't make anyones life harder than it needs to be. In the odd occasion we may need a little more info but for most the above will do the job more than adequately.
© Chains Ropes and Anchors 2014