Decoding an SFIC control key by pin measurements?

[ridinplugspinnaz]

So at long last, I was finally able to pick my Best core to the control shear line (which is an amazing feeling, let me tell you!). Now that I've been able to do that, I'd really like to file a control key for myself so I can remove the core in the future.

So far, I've been able to remove the pin stacks in order and measure them with an electronic caliper, so I have measurements of all the key pins and spacer pins. I suspect that all I need to know at this point is by how many thousandths of an inch the control shear line sits above the "bottom" of the keyway (I guess this would effectively be the 9-cut?) to make the proper key. The logic being that the equation:

(Length of key pin + length of spacer pins up to the topmost cut in the stack + x) = height of the control shear line, where x ends up being the height above the "bottom" of the keyway to be provided by the appropriately-cut key bitting for each stack

...is all I should need to decipher the control bitting without a lot of guess-and-check with a keyblank and a file.

Anyway, for those of you SFIC gurus out there, can you advise on how I can cut a control key for my lock based simply on the measurements I've taken of all of the pin stack elements? I'd prefer not to wait another two months of random picking before I can move the control lug again Thanks!

[keysman]

....Anyway, for those of you SFIC gurus out there, can you advise on how I can cut a control key for my lock based simply on the measurements I've taken of all of the pin stack elements? I'd prefer not to wait another two months of random picking before I can move the control lug again Thanks!

I have a PDF that explains the procedure... PM me your e-mail and I will foward you a copy (361K)

Keysman

[ridinplugspinnaz]

....Anyway, for those of you SFIC gurus out there, can you advise on how I can cut a control key for my lock based simply on the measurements I've taken of all of the pin stack elements? I'd prefer not to wait another two months of random picking before I can move the control lug again Thanks!

I have a PDF that explains the procedure... PM me your e-mail and I will foward you a copy (361K)

Keysman

Awesome, I really appreciate the advice. PM sent.

[ridinplugspinnaz]

Okay, I've found that I'm still at least a bit confused here, I think owing mostly to the way that writeup was composed. The table converting pin lengths to wafer numbers was really useful, and I've done those conversions. In the case of the control key I was able to figure out what they were getting at, but here's where I'm confused:

"The next step you may like to use is to remove the pins used in the core combination and place them in the right order with the top pins collected. Measure those second set of pins and calculate this information of two pins per chamber plus ten. With this new information, deduct this from 23 and you have now the combination of the regular or working shear line."

I think what's tripping me up here is that the cylinder I have here is mastered, so I'm dealing with three cuts per pin stack, and not two like the article seems to assume in some illustrations. The part I don't understand is what wafers I'm supposed to add together, to later be subtracted from 23. Is it the driver plus the adjacent master wafer? Just the two master wafers? When (if ever) am I supposed to add 10? Can anyone shed some more light on the specific math I'm supposed to use to derive the operating pin stack cuts once I know all the wafer numbers?

[keysman]

"The next step you may like to use is to remove the pins used in the core combination and place them in the right order with the top pins collected. Measure those second set of pins and calculate this information of two pins per chamber plus ten.?

Follow the example below, yes the PDF was a bit confusing, but the basic info is there:
What they are trying to say is IGNOR the top pin , add the bottom pins together
( not important if there is 2, 3 or 4) and subtract 10... this will give you the control cut.
This is the most reliable method.. as I know one of the largest " Best" distibuters in the USA
frequently uses a " wrong" size for the top pin .. it doesen't really have any function except
to tension the spring and a size or 2 off won't really effect it at all.

Keys:
Control 6 5 2 3 4 3 0
Master 2 3 4 5 6 7 8
Change 0 1 2 3 4 5 6

Pins:
Top 7 8 B A 9 A D
Master E C 8 8 8 6 2
Master 2 2 2 2 2 2 2
Bottom 0 1 2 3 4 5 6

Substitute the letter for the number below .. I was having trouble getting the columns to line up
10=A
11=B
12=C
13=D
14=E

[bthom73]

I'm been trying to learn the some of the same calculations and if I understand it correctly the following should work and there's a few different ways you can do it:

If there's a total of four pins per chamber (top driver/control/master/bottom), that most likely means that the lock is mastered for change keys but only has a single control key. Next verify that all of the chambers are properly pinned (that their increments add up to 23). If so, the control key cut for each chamber should be 13 minus the top driver pin.

If you have one or more chambers that were mispinned and don't add up to 23 (for example 22 or 24), you have to start in the other direction by calculating from the bottom up. To do that, add the bottom pin number and the master pin number together and call that "A". Then measure the control pin and call that "B". Calculate 10 minus "A" and call that "C". Your control key cut should then be equal to "B" minus "C".

Again, don't rely on the above since I'm learning too...but from what I understand it should work.

[Raymond]

You are definitely on the right track. If all the pins are removed and lain in order of top on top, all master wafers, and bottom on bottom, then the sum of the bottom pin and all wafers (exclude the top pin) will be the control cut plus 10.

Example: top: 5, control wafer: 10, wafers: 4 and 2, bottom pin: 2. This example is correctly pinned using the correct top pin. Therefore a 5 top pin represents a 8 control cut. Note that the bottom, wafers and control add to 18. 18 minus 10 equals 8.

pins
5 by the chart this should indicate a control cut of 8.
10 10
4 4
2 2
2 2 sum of bottom stack = 18. 18 - 10 = 8. Control cut = 8.

23 sum of all

If some locksmith pinned the stack with the incorrect top pin, the measurement of the bottom stack will still be accurate.

4 wrong top pin; by the chart this should indicate a control cut of 9.
10 10
4 4
2 2
2 2 sum of bottom stack = 18. 18 - 10 = 8. Control cut = 8.

22 sum of all. Incorrect total.


You can also determine a chart that will allow you to measure through the holes in the bottom of the picked core. The distance from the outside of the core to the point on the bottom pin will tell you the control cut. I haven't bothered to do this yet but now that I have thought of it I guess I will have to make a depth gauge for this purpose.

[ridinplugspinnaz]

You can also determine a chart that will allow you to measure through the holes in the bottom of the picked core. The distance from the outside of the core to the point on the bottom pin will tell you the control cut. I haven't bothered to do this yet but now that I have thought of it I guess I will have to make a depth gauge for this purpose.

Correct me if I'm wrong, but doesn't the fact that all the pin stacks are spring-loaded defeat this method of querying the lock? If the core is properly combinated and the springs are working properly, shouldn't all the key pins be resting at the same position?

[ridinplugspinnaz]

Hmm, perhaps I misunderstood you. I suppose if you compressed all the pin stacks fully, you can obviate the problem of the springs, but if the stacks are properly combinated, then they all add up to 23 and the distance mesaured should still end up the same. All that is also completely disregarding the fact that springs compress in funny ways a lot of the time, and all it takes is 0.0125" to throw your decoding off by the distance between one cut in the key.

Anyway, I would really like to hear more about this method if you're been able to do it successfully in the past, but I'm having trouble seeing how it would work so far.

[ridinplugspinnaz]

Hmm.... I think I misunderstood you yet again. It sounds like you're suggesting that the core be rotated 180 degrees after it's picked open, and then the remaining pins are interrogated with a small probe. That actually makes a lot more sense, save for a couple problems that I foresee. First, you still have the inherently poor tolerances of dealing with the compressed springs in your measurement, and secondly it may be impossible to tell if your picking job left the master wafer in the plug or not once you were able to turn the cylinder. You'd also run the very real risk of knocking loose said master wafers during your interrogation of the driver / control pins.

...anyway that was entirely too much rapid-fire posting, so I'll cool it for now, but I am very curious to see you describe this method in more detail.

[Raymond]

Sorry folks,

I shouldn't be trying to answer questions so late and without sleep. I should slap myself silly to have even suggested that last method of decoding the control. Today, I realized what I had proposed and instantly realized that the rotation of the control sleeve blocks access to the holes. There might be some room if it is rotated back to "just before the pins drop" to insert a very thin wire but I doubt it. Just stick with the bottom stack sum method and it will work for you.

[Raymond]

Can someone tell me how to turn off the center justification so my example will make sense? It looks correct when I write it.

[WOT]

There's design specs... and there's real world. There are more than one ways to decode the control key... and my usual method works for a properly pinned stack, but the other method (which I don't remember anymore) must be used to derive the control butting for illegal stacks (such as A2 stack that adds up to 22, or 24, etc). keysman... perhaps you might remember?

~SFIC.WOT