Assembling a Cylinder
It’s not too difficult to assemble a cylinder, if you have enough practice. The problem is that most of us don’t get enough practice. Most of our cylinders come straight out of the box or are made to order, and it’s only on occasion that we need to build ones ourselves.
Step 1: Disassembling the 1-bitted cylinder
It’s rare that you’d build a cylinder from scratch (unless of course you work in a cylinder factory). Instead, you’d take a pre-prepared cylinder of the type you need, where all of the locking pins are of the same size (usually size 1, hence the term 1-bitted). You need to take out the plug (the part with all the pins in) before you can pin it up.
It’s easy enough to do this, though you need to take a few precautions if you want to be successful: you need to put a ‘pinning shoe’ into the cylinder so that the sprung bottom pins don’t jump out, and you need to make sure that as few of the moving parts inside the cylinder move out of place as possible.
The more disarray there is inside, the more you’ll have to meticulously put back in place before your job is done.
What can go wrong: The main thing that goes wrong in this stage is that the bottom pins jump out. This means you need to re-pin the bottom section, which is often fiddly and irritating.
Step 2: Pinning the plug
This part is quite straightforward: you just make sure all the pins of the right size end up in the right hole in the plug. What you need to do is create a shear line so that, when the key is put into the plug, all of the pins are flush.
What can go wrong: Not all that much can go wrong here, thankfully. If your cylinder has a sidebar or any other special feature like that, it’s important you put it into the plug here, otherwise you will have problems down the line.
Step 3: Putting the plug back into the cylinder
This is one of the trickiest parts, as it’s here that any of the problems from the previous two stages will come home to roost. In theory—in theory—you can just slide the plug back into the cylinder body and the job is done. In practice, that’s never the case. There’s always something you need to adjust before the plug will fit.
The plug needs to slot into the cam, which is the bit in the centre of the cylinder that ultimately throws the bolt. When you turn the key, the key turns the plug, the plug turns the cam and the cam throws the bolt.
However, often it’s a series of small, fiddly parts that joins the plug to the cam. If any one of these parts is missing or in the wrong place, then the cam won’t turn, and you’ll have to start all over again. (Sometimes errors in Step 3 mean you need to chuck the whole cylinder away!)
Usually you’ll need to nudge a few pieces into position, and make sure the cam is properly aligned before the plug goes back in. Once the plug is in, you’re practically home free.
What can go wrong: Everything can go wrong here. You must always have your wits about you at this stage.
Step 4: The final twist, and circlip
Once you’ve put the plug back in, you’ll need to turn it 180 degrees, so that the keyhole is the right way up. It sounds easy, but even this can go wrong on some cylinders.
Once the plug is in, you need to fix it in place using a circlip. This prevents the plug from being pulled out whenever you put a key in. Then you’re done. All you need to do now is to test the key in the cylinder. If all has gone well, then the key will work without any trouble.
What can go wrong: If your cylinder has a sidebar, then you need to make sure you turn the key the right way round before putting the circlip on, otherwise the cylinder might seize up. You might also forget to put the circlip on before testing, and thereby accidentally pull out the plug (I’ve been guilty of this often). Sometimes the key will turn, but not hugely well. Often, the solution is just to tap the cylinder firmly a few times. It might just be that one of the springs is stuck, and the tap will loosen it back into place.
Congratulations, you’ve just pinned up a cylinder!