Photo by Matt Blaze
Spool pins are among the most popular type of security pin you will find in common pin tumbler locks. In recent years it has become common for manufacturers to put them in even the cheapest of lock cylinders. Their sole purpose is to frustrate you, the lock picker. In common household deadbolts they can be a minor inconvenience to picking; in well made locks they can be quite challenging; in some dimple locks they can be devastating.
A spool pin has a smaller diameter along the center of the shaft than it does at the ends. See illus. (needed) to see a spool pin. Spool pins are exclusively used as driver pins, as their purpose is to get stuck at the shear line. Since the key pin should never cross the shear line, there is no point to using a spool pin as a key pin. Because of the design of a spool pin, when the upper ridge at the top of the spool pin crosses the shear line the plug is allowed to rotate quite significantly. This exaggerated rotation is the telltale sign of a spool pin. Once the plug has rotated (usually around 10°) the spool pin becomes trapped. The lower ridge of the spool pin will get stuck at the ledge of the shear line, not allowing the pin to be easily lifted.
Though it requires some patience and practice, this can often be overcome if you know how to handle it. Once you detect that the lock has just been trapped on a spool pin (again, you will know because of the exaggerated rotation of the plug) there are some specific actions that you can take to get the pin past the ledge and above the shear line. It can be a bit finicky, but with practice you will find that these pins rarely so much as slow you down in anything but the very well-manufactured locks.
To verify that you are in fact trapped on a spool pin, maintain light tension and begin to apply upward pressure on the pin stack – using somewhat more force than you would normally use. Pay careful attention to the feedback you are getting from the tension wrench. If you feel the plug fighting against you, as if trying to turn back, you will know that, indeed, you are stuck on a spool. To overcome this, simply (admittedly, not so simply at first) lighten up your tension, taking care not to lighten it so much that you begin dropping pins that have already been set, and apply some extra force to the pin stack. If all goes well, the ridge of the spool pin will clear the shear line and the pin will be set.
There are two common issues that arise while trying to set spool pins, and only a good measure of practice will help you to prevent these issues from occurring. The first, and most common, is that of un-setting – or dropping – already set pin stacks while trying to set the spool. This comes as a result of lightening up too much on your tension, or using so much force while pushing the spool pin past the shear line that you jostle other pins causing them to dislodge and drop back into the keyway.
The second, and equally frustrating occurrence is that of over-setting a the pin stack with the spool. Because of the extra force needed to push the spool past the ledge at the shear line, it is easy to push the key pin past the shear line as well and get it trapped there. Like any other time you have a pin stack false set high, you can sometimes fix this simply be reducing tension and allowing the pin to drop back, though you will likely drop other pins and have to start again.
Picking spool pins is something that many novices find frustrating. Once again, we can take a very simple and methodical approach to learning the technique. If you do not already have a selection of security pins, now would be the time to acquire them. Unfortunately, without salvaging pins from old locks, these can sometime be a little tricky to acquire if you are not a locksmith. Local locksmiths and locksmith supply shops will sometimes sell small quantities of security pins, though often not. Many locksmith suppliers will sell large quantities of security pins (a box of 250 or more) for a reasonable price.
Once you have acquired your assortment of security pins, we are ready to proceed with a practical exercise to help you develop the feel and skills needed to successfully pick spool pins. Re-pin your practice lock with all pin stacks installed. Insure that one (and only one) of these pins stacks has a spool pin. It is preferable that you install the spool pin somewhere in the middle of the binding order, so it will be neither the first, not the last to set. For our example, we will assume that the lock binds in the order 1-2-3-4-5 and you’ve installed the spool pin in position 3. Begin picking the lock as usual, but when you get to pin 3, pay special attention while lifting this pin stack. When the upper ridge of the spool clears the shear line you will feel the exaggerated rotation of the plug. Begin to follow the instructions listed above for defeating spool pins. It may take you several tries at first, so be patient and diligent in your practice.
Once you have successfully mastered defeating this single spool pin, re-pin the lock by adding an additional spool in whichever position you like. Repeat the process and move up to a third and fourth spool pin. Once complete, try the same exercise on another lock. If you follow this method closely you will be picking spool pins in no time.
Full credit to: lockpickernetwork.wikidot.com