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Finally getting around to combinating a couple SFIC cores lying around, and thought it might be good to make a pictorial writeup while I did so. While I have some knowledge of these locks, the professional locksmiths here who work with them will know a great deal more than me. Please feel free to correct anything incorrect, as there is much of which I am ignorant. My thanks to MrWizard, who taught me a lot. Hopefully I remember it correctly!

To start with, here are the bittings of the two keys to be used in this core…



For those not familiar with the terms, a control key is used strictly to remove the lock core. A change key (also known as an operating key) is used to unlock or lock the core, but will not remove the core.

SFIC locks use a tip-stopped key. The bottom of the key has a flat tip that stops the key from entering further into the lock core. Due to this, the bittings are numbered from the tip of the key to the bow, instead of the other way as in many other locks.



Here is another key. This one is for a 5 pin lock.



The SFIC keys are made so they can be cut further from the tip to make them usable in 5, 6 or 7 pin locks. For example, the key above could be used in a five pin core with the bitting 84848, a six pin core with the bitting 848480, or a seven pin core with the bitting 8484800.

There are two sheer lines in a SFIC, as opposed to a standard lock. The operating sheer line is closest to the key, and the control sheer line is further from the key. The difference between the two sheer lines is .125”. This greatly complicates pinning these cores, and will not go into greater detail right now. Will keep this ‘simple’, and not address master keying at this time.

Why no extra detail at this time? Well, here is an example. Here is the pinning chart for the pins in each chamber of the core as required for the change key and the control key…



Here are the pins in the chart above. The pins are upside down from the way they will be in the lock core. Have found this to be an easier way to load the cores.



Here you can see the change key will fit the bottom pins (key pins)...



And here is the control key over the pins.



This is a pinning block for SFIC cores. It holds the lock core while you load the pins…



It is best to test the keys and pins before you cap the pin chambers. The pinning block helps with this. Here is the back of the lock core, with the control key inserted, then turned. You can see the control sheer line in the normal position in the first picture…



And with the control key turned. If the core were still in the housing, it could now be removed.



Now the core in normal position with the change (operating) key inserted…



And the change key turned…



OK, we know the keys will work in the lock. So now put the core into the capping block with the top of the core at the top like this:



Load the springs into each pin channel



And one cap in each channel:



Verify each pin channel has a cap in place by looking in from the top of the capping block:



This is a capping tool. It is used to seat the caps in the top of the pin channels.



Place it into each pin channel like this:



Now give a sharp rap with a rawhide or plastic hammer to seat the caps.



before seating:



after seating:



The capped core:



Change key works:



Control key works:



Here is an American 3200 padlock which will be the home for this ‘R’ keyway core:







Using the control key to install (or remove) the core:







And the change key works!



The tools used:



Now as a quick add-on, here is one of two ‘WY’ cores that I received.



No keys came with the cores, so here is how you can take these cores apart and find the bittings.

Needed tools:



This is the ‘book’ that the pins will be punched out of the core into for decoding.



The top of the SFIC cores have the caps, and larger holes.



The bottom of the core has smaller holes. The tool enters here and forces the pins, springs, and caps out the top of the core.



Load the book into the capping block



until it seats flush.



Put the core to be decoded in the capping block upside down



Place the long tool into the pin channel.



and tap it with a rawhide or plastic hammer. Very light force is needed. No need to act like you are hammering a nail into hard wood.



Once you have done that in all the pin chambers, you can remove the core.





And remove the book. Note: Keep the book with the open side of the pin channels up, or the pins, springs and caps will fall out. Yes, I had to learn this the hard way.



Open the book, and see all the pins, springs and caps. Each pin channel is organized and labelled - so easy!



Note how the pin stacks are identical length (combined). This is called ‘balanced stacks’, and is rather important for SFIC locks.



Again, the bittings are numbered from the tip of the key, not the bow.



Measured the pins and decoded the control key as 2733557. The key pins would work out to a bottom level change key of 5421370, and six of the seven pin channels have master pins. If my calculations are correct, that would give 64 possible change key permutations that would fit this lock core, plus the control key.

OK, that should be enough misinformation for now!

Questions? Comments? Corrections? Please post them, so we can all learn.

Gordon

Very cool writeup! SFIC locks are fascinating to me.

Well that is one heck of a post Gordon!

It might be the late hour but I believe you hit on the basics. An important thing is to never use a metal hammer when capping or decapping cores. You will damage your capping block and pins. I think yours had seen some heavy uses both with and without a metal hammer before you bought it.

Didn't buy it. The lockies at a shop I haunt were bitching about it being worn. So I told the owner, I'd give him 20 bucks towards a new one for the shop as a joke. He ordered another one, and told me to keep the old one. Some minor file work and it works fine for my limited needs.

Gordon

*Shear.

Well that's a 'how-to' and a half! Good work. How is the core held into the body of the padlock? Does the control key turn the lock further which disengages it?

Nice writeup.
I use A-1 combinating and capping blocks but they are similar. I learned the hard way not to use a metal hammer when combinating cores.
Deadlock, the control key moves the control lug which is what holds the core into a padlock or housing.
First pic, control lug in its normal locked position.

Second pic, control lug unlocked for core removal.

Thanks jeffmoss. Any Brits know if this lock or anything like it was, or is, sold over here?

Seen from the back of the core, you can see that the center right of the core in the picture sticks out...



And with the control key turned, the lug is turned to retract it into the core...



That lug sticks out from the side of the core from the back of the core towards the front for the length of the first four pins (from the tip of the key), though the shear line actually covers all seven pins.



Inside the lock housing, there is a milled space that that lug fits into when the core is installed. Forward of that milled area is the familiar figure 8 shape of the SFIC, and that is what keeps the core from being withdrawn until the lug is retracted.

Gordon

Thanks Gordon.

Excellent post, Gordon. I had to turn down a very big job last week because I didn't have the tools or the know-how to work on these locks. Now I need to figure out where I can get all of those wonderful toys.

Hate to make this post even more picture heavy, but from questions asked both in the thread and in PMs, here is a little more info on the regular shear line and control shear line.

Seen from the front, on the left side of this picture, you can see that the control lug is sticking out, unable to be removed from the housing. (Please ignore the fact that this core has been drilled.)



And the control lug retracted, leaving a nice '8' shape that can be removed from the housing.



Angled view - lug sticking out



Angled view, lug retracted



On the left is the center plug, which is the 'operating' shear line. In the center is the control plug, with the control shear line, and the main SFIC core.



Same order, but with the shear lines/pin channels visible



The control plug is removed/installed into the SFIC core from the rear





Then the center plug is installed from the front.





That should help you to visualize what is happening inside the SFIC with the two shear lines.

Gordon

Great write up Gordon. Very well done.

Gordon,
The drill point on the core..........was that done to put tension on the control lug so it could picked to control?
Kind of like a side bar?

Guess I'm asking, drill bit size and depth. Looks like the hole was drilled to remove the core without damage to the housing.

That way you just end up replacing the core not the lock.

I have some BEST knobs that refuse to pick any other way than open. Guess that makes them NON-removable cores.(for me).

Want to pull one apart but also not ruin the lock.

The drill point is to try drilling off the control lug, but without damaging the pins. I use a very small drill bit at first to get the hole started and straight, then a larger bit that will cut off the lug. As you correctly figured, it allows you to remove the lock core without damaging the housing, so you only need to replace the core. Yes, you can drill the pin shear line, but am in the habit of trying for the lug instead.

This way, since the pins are undamaged, you can still punch out the pins from the core and decode them, and make a control key to remove other cores that were pinned with the same control key. Much faster. This core was one of five that needed to be removed, so drilled this one, punched and decoded the pins, made a control key, and removed the other cores quickly and easily. Then the other four cores could be recombinated (repinned) and reused.

For some reason, when I drilled this one, before I actually completely finished drilling off the control lug, the control shear line popped over, just as if the control key was used. Go figure! But it left me with parts I could use for these pictures. Knew there had to be a reason I didn't trash it a month ago!

Gordon

Great thread Gordon!

Thanks for taking the time to document + post your efforts.
I am finally starting to understand how SFIC work - thanks to you.

Cheers,
Sean