Questions: Impressioning IC

[madsamurai]

So I'm about to spend the next few days impressioning keys for a bunch of locks I don't have keys for, and a number of them are interchangeable core. The goal would be to impression both an operator key and a control key for these, if possible. As I'm thinking about this, a couple of likely problematic scenarios come to mind:

1) The first shear line reached on all pins is either operator or control. Now the key turns, so no more marks. How would I continue to find the other key?

2) Some pins reach operator shear line and some reach control shear line, so all pins are at a shear line and thus no more marks, but the key doesn't work at all. How to figure out which pins to progress?

Thanks

[Riyame]

Which IC are you trying to impression? SFIC? LFIC? If LFIC, which maker?

[madsamurai]

Which IC are you trying to impression? SFIC? LFIC? If LFIC, which maker?

I have two Best SFIC and a Corbin/Russwin IC (not high security). Does it make a difference? Seems like these potentials would apply to any (excluding the ones that use a rear control pin, like my Yale LFIC and Schlage Primus).

[madsamurai]

So I've been pondering this, and I think I've worked out some of it in my head... let me know if I'm on the right track here...

1) the only real problem occurs if all pins reach operator shear line first, since if they all hit control first we can just pull out the cylinder and measure pins to get operator key bitting(s)... tho part of me wants to consider that cheating since this is an impressiononing excercise. My theory here is once we've impressioned to operator, we'd have to make a duplicate of our key and file one of the control chambers (that choice of pins would be model dependent) down a step, which should bind and create marks until it reaches the control shear line, then should transfer tension to the control sleeve and cause the other control chambers to bind at the control shear instead of the operating shear line, creating the marks we need to find the rest. That depends on the assumption that all control chambers have control BU pins, and I'm not sure if that's always the case (also model dependent, maybe).

2) if any pin reaches the control shear line, then that should cause any other control chambers to bind at the control shear rather than the operator shear, so impression marks would continue until all of the pins were at control. So a case where we get some at control and others at operator doesn't seem like it would actually happen.

[Riyame]

Well, SFIC have control pins in every chamber. I believe Russwins have 2 control pins. I know I will be corrected if I am wrong on that . Some LFICs have 1 control pin, some have more. Some turn to control CW and some are CCW. That can all make a difference when you are trying to impression.

[tpark]

Since there are two shear lines for SFIC cores, and the pattern of the control key is independent of the operating key, you have the situation where the pin is may be bound even though one of the shearlines is correct. If this occurs, marks will appear on the key, causing you to file past that key depth.

I think the easiest way to deal with SFIC is to pick to control, remove them from the lock assembly, then decode the core.

Schlage LFIC only has one shear line, so you should be able to impression those. Once you have an operating key, just cut the pattern onto a control key blank and you have a control key.

Sargent LFIC turns counterclockwise to release the core - the middle two pins are different for the control key on these cores, so it may be possible to impression to get the first two and the last two pins.

I generally only impression locks which I can't get apart. In some cases, I can pick the lock, then measure the pin height in the keyway from the picked position, then make a key from that information. If I don't have it quite right, I can look at where the marks are on the key, and go from there.

[selim]

Great post Riy , but the corbin russwin IC's that I do have 4 control pins. I didn't realy know until a few years ago. ( that's why xeo could pick them to control before operating. The corbin control keys from the fackory come with the 3rd & 4th position cut to the depth of 3. I didn't know any better at the time.

tpark you post was good also, and your box got sent today

[madsamurai]

For the record, the Corbin IC I have has 4 control pins, and from looking at my C/R cylinder manual here (thanks, mastersmith), the high security (Emhart) IC cylinders have 2 control pins.

Either way, I can see the importance of knowing the lock you're dealing with...

tpark, I agree that's probably the most efficient method in practice (assuming one can consistently pick to control, which I haven't been able to manage yet... can pick these open all day long, but control is still elusive). This particular case is more of an impressioning exercise for me, to try and see what the limits of this particular method are, and when it would be useful and entirely un-useful... so if there's a way to do it with just impressioning, I'd like to figure it out, even if it's not the easiest/best way to come up with keys in real life (it is, in fact, probably the last option I'd consider if I was doing an actual job where IC locks are in use). If I'm completely wasting my time, that's good to know, too, but I'd like to have a full understanding of why it'll never work if that's the case... and for me that usually means experiencing it not working

[Farmerfreak]

For Best SFIC, the problem is that you have zero control over what shearline you are getting marks from. There are 7 spaces, in each one the control cut is either shallower/the same/or deeper than the operating key cut. What do you think happens if the control key bitting is 3555557, and the operating key bitting is 7555553. You just impressiong a key to 3555553. The lock just turned a tiny bit further than previously, awesome, you're close! Now what, which pin marks? Do both 3 depths mark? Is there anyway to know which pin needs to be deeper to get a control key? I haven't tried to impression one in over 10 years because I couldn't figure it out with any kind of consistency. And the example I gave is far simpler than what it is in reality.

Odds are the lock will be masterkeyed and have multiple operating keys. Control key will have only one combination. So you are likely to get an operating key if any working key at all.

Oh, and a lot of the locks have spooled master/buildup pins. That isn't going to help. The pin kits we have at work have the 6, 8, and 10 master/buildup pins spooled.

If you can figure it out and impression them with any consistency. I'd be interested to know.

[plugspin]

Would be interesting to see your results. I had written off trying to impression IC cores a long time ago due to the dual shear-line issue as described by tpark. I recall watching Barry Wels unsuccessfully attemptming this at a LockCon years ago, but I belive that was his first time trying it (an SFIC core). He may have had more success later on though.

[madsamurai]

Farmerfreak, that's exactly the scenario that initially occurred to me. Each pin is going to stop marking at the first shear line it reaches, whether that's operating or control. I could end up with any number of pins on either shear line, and have no idea how to figure out which pins are on which. Duplicating and trying different pins could mean dozens of blanks worth of trial/error, especially once you consider master pins. I'm starting to see how it's potentially so much worse than what I was first worried about... I'm glad I posted this question before I started...

So here's a thought, just for the sake of continuing this fun (to me, at least) mental exercise... could we use impressioning as a way of measuring the pin stacks? Rather than hoping to find the correct shear point, what if could we find all of the shear points for each pin? If we follow the marks on each pin to the first shear point, then continue down until we reach the next one, etc, and record the bitting of each stop, could we discover the pin stacking and then deduce a control bitting from those numbers? I'm thinking maybe not since we'd be getting measurements based on two shear points rather than a single one (plus spools)... but if we know the specs of the lock we might be able to determine which stopping point could be the only potential control shear height for each pin, then create a key from that.

Thoughts? (you won't hurt my feelings if you call me crazy )

[Farmerfreak]

could we use impressioning as a way of measuring the pin stacks? Rather than hoping to find the correct shear point, what if could we find all of the shear points for each pin? If we follow the marks on each pin to the first shear point, then continue down until we reach the next one, etc, and record the bitting of each stop, could we discover the pin stacking and then deduce a control bitting from those numbers?

Assuming that it's even possible to accurately record the bitting of each stop.. If the lock was masterkeyed, you would get 1-3 possibilities for each of the seven spaces. I still don't see how the control bitting could be figured out from that. Maybe with enough blanks and time, even though I don't like picking these for the same reasons. At least with picking, different combinations can be tried at a much faster rate than cutting/filing new keys. There are also other tricks with picking that can't really be done with impressioning.

Now if you could find a reasonable way of locking the outer control core to the inner core. Then you should be able to impression it like normal. Maybe it's possible to put some small shims in the bottom of the keyway and slide them under and around the cylinder enough to lock it in place. Never tried it, don't really think it's practical, the idea of wedging a shim in it just barely came to me. Then of course, would need to be able to get the shim back out.

[Oldfast]

Chad, I've gotta say... since you've come on, it's been a real treat to follow
along as you jump around and tackle a wide variety of different things here.

I just admire the way you're able to approach things and think outside the box -
something I've never been all too good at. Your brain obviously works differently
(aka better, lol) than mine when it comes to that.

A few years back, during my 'impressioning frenzy', I recall wanting to try what we're
discussing here. Maybe it's a good thing I never gave it a good try, as it's looking like
I could've very well gotten lost in the matrix..... and maybe still be there today! lol

Farmerfreak.... very nice to see you sir.

[madsamurai]

Thanks, Oldfast. That's quite a compliment, especially coming from you. I've learned a ton from reading your posts. I'm glad you're enjoying mine

[madsamurai]

Coming back around to this old topic, I just had an idea and wanted to run it by you guys and get your thoughts... it seems to me the key to making this possible is locking the control sleeve to the plug so the key blank will always be putting tension at the control shear line. Call me crazy, or even call it cheating, but has anyone ever tried glue? I was thinking a needle-applied few drops of CA glue (or some other dissolvable adhesive) along the bottom edge of the keyway would bind the control sleeve to the plug, thus the key would apply pressure exclusively on the control shear line. Then you could impression the control key, remove the core and soak it in acetone or some such to remove the glue. Just thinking out loud, but am I maybe onto something here?