Altering SFIC?

[Tyler J. Thomas]

I've been watching some bosnianbill videos lately, specifically his challenge lock videos. Nearly always the same (security pins) although sometimes they'll get creative and tap chamber holes or enlarge them to mess with him. The latter gave me an idea for an SFIC that I might send to him. I might be missing something so I'm running it by you guys before I go through the effort.

SFIC's have two shearlines: control and operating.

My idea: slightly enlarging alternating chambers at both shear lines. For example, enlarged chambers in 1, 3, 5, and 7 positions on the operating shearline. Enlarged chambers in the 2, 4, and 6 positions on the control shearline.

The thinking is that both shearlines will attempt to pick, which would then give the feeling of being "set" and potentially cancel each other out. There is enough play in the control lug that even if you attempted to pick it counterclockwise, it would still give the same effect - at least in my head. But that's my head and I don't pick or play around with cylinders hardly anymore so I might be missing something.

What say you?

[cledry]

So are you for the operating shearline enlarging just the plug, not the control lug shearline and bible vice versa? Then you would use a larger diameter pin or is it just to allow the stadard diameter pin to flop around? Trying to get my head around what you are doing.

[Tyler J. Thomas]

So are you for the operating shearline enlarging just the plug, not the control lug shearline and bible vice versa? Then you would use a larger diameter pin or is it just to allow the stadard diameter pin to flop around? Trying to get my head around what you are doing.

Enlarging the diameter of the chamber for each respective shearline.

In other words, disassembling the core, drilling the appropriate chambers of the control lug and/or plug partially, reassembling, and pinning.

Enlarging chambers 2, 4, 6 of the control lug. 1, 3, 5, 7 of the plug.

[Tyler J. Thomas]

And not fully. Haven't decided on the depth but drilling from the top of each portion disassembled. Just enough to catch the control or top pin, depending on which part.

[femurat]

I think it should work well. May want to try it myself when I have some time.

Good idea

[Tyler J. Thomas]

Thanks.

Going to try it on an "F" keyway core today (have a lot of spares), I'll post pictures when complete. If all goes well then I'll start figuring out the best way to pin it up. One step at a time.

[Tyler J. Thomas]

Here's a quick demo just to illustrate the principle:

[jeffmoss26]

Oh man, this is gonna be good!!

[Tyler J. Thomas]

Here's the key chart:



You'll notice that it alternates with a pattern for each reamed chamber. The point for this is that very minimal pick movement will lift either the bottom or control pin to the reamed shearline and it will take a lot for every other chamber to reach it's intended shearline. An added benefit is that there's a 1 bottom pin behind each 9 pin so it will take some extra dexterity as you move into the chamber.

So, for example, in the first chamber you will have to raise the stack by something like .2375" to reach the control shearline but only something like .0125" for the operating shearline. In the second chamber, raising the stack by .0125" will reach the control shearline but it will take .125" to reach the operating shearline. And so on and so forth for the remaining 5 stacks.

I'm guessing at those numbers because I don't know the EFD of this core off the top of my head but the coded difference between both shearlines is always 10, or .125" or 1/8". Either way, the numbers are close and illustrate how moving the stack up with the smallest amount of lift will, hopefully, result in a set stack at either one of the shearlines.

Sending him an X2W keyway (tightest keyway) Cormax core in a mortise housing; hopefully tomorrow.

[jeffmoss26]

We do a lot of CORMAX here - I love those evil keyways.

[Tyler J. Thomas]

Pinned it up. I guess I reamed the chambers correctly because inserting, turning, and removing the key results in at least one binding chamber - I can hear the free floating pins moving. Tapping it a bit resets them.

I'll try picking it later and see if I can pull it off.

[Tyler J. Thomas]

Played around picking it today. No dice.

After I originally drilled the chambers, I sanded the control lug up to 1000 grit. I left the plug itself alone. Because of the burrs, it's a tight fit. As a result, you have to increase tension to set any chamber, thus increasing the chances you set at the opposite shearline of whatever you're picking for.

I'll throw it in a housing tomorrow and send it out. Can't wait to see if he can pick it.

[kwoswalt99-]

I don't think he can reliably pick normal sfic locks. If he can't pick it, it may not get a video.

[Tyler J. Thomas]

I don't think he can reliably pick normal sfic locks. If he can't pick it, it may not get a video.

Really? Dang. Well, hopefully he will. If not, can't say I didn't try.

[jeffmoss26]

You inspired me to pin up a core myself: