how do i make a change key

[horsefeathers]

i have been given this Arrow ic lock



rarer than hen's teeth here in the UK - got 3 keys as you can see (and have blanks) - so how do i make a change key? Is there one cut on the original key that i need to make longer/shorter?

[ARF-GEF]

I don't think it's predetermined. So I doubt it works like" raise the last cut by 2 steps and you have the control".
Sorry for the bad news. I hope I'm wrong

[LockDocWa]

When you say "Change-Key "
Are you in fact referring to a " Control " key?
Are you looking for the key which is used to extract and replace the cylinder?
The key that performs that function is the Control key.

[jeffmoss26]

Yeah, my guess is that he wants to make a control key.
I have several sources that can decode and cut keys for cores but they are all in the USA.

[horsefeathers]

control key, yes

[keysman]

take a look at this:

http://www.lsamichigan.org/Tech/Keynotes_Apr08.pdf

[Squelchtone]

take a look at this:

http://www.lsamichigan.org/Tech/Keynotes_Apr08.pdf

That's the most helpful thing I've seen on the forum in ages. VERY good info!

Thanks keysman!

Squelchtone

[ARF-GEF]

That's the most helpful thing I've seen on the forum in ages. VERY good info!

Thanks keysman!

+1

[IndigoChild]

Usually the sfic are controlled by the third pin. I dont know if that is all you have to change or not but its worth a try. But usually the control is on a whole different bitting than the rest of the system.

[FarmerFreak]

Usually the sfic are controlled by the third pin.

I'm not sure where you got that info from, but I'd suggest you forget it in regards to SFIC.. The only relevance the control key has with the regular keys is that they are A: the same keyway. And B: usually, but not always, the same even/odd cut pattern that the regular keys use. (for example, if a regular change key had the bitting of 414661, the control key will likely have cuts of even, odd, even, even, even, odd)

[horsefeathers]

i have fully stripped the entire lock down and removed carefully all pins.

i can see now that from the original key the 7 cut needs to be one step higher, 3 one step lower and 1 two steps lower. So later today will cut a key hopefully with that biting. The pins were colour coded and it appears that any 'green' control pins were of the correct height so the corresponding biting need not be touched on original key.

nice link btw

[ARF-GEF]

Sorry people you lost me here.
I thought the control biting is totally independent from the operating key's biting.
As Farmerfreak wrote I thought too that the only common thing is the same profile, although I suspect in bigger systems the key profile might be master keyed. (?)

The only restriction is that they can't have the same biting.
How can you deduct the control key from the operating one? The whole point is that it's not possible to escalate your rights into control?

[IndigoChild]

Usually the sfic are controlled by the third pin.

I'm not sure where you got that info from, but I'd suggest you forget it in regards to SFIC.. The only relevance the control key has with the regular keys is that they are A: the same keyway. And B: usually, but not always, the same even/odd cut pattern that the regular keys use. (for example, if a regular change key had the bitting of 414661, the control key will likely have cuts of even, odd, even, even, even, odd)

Perhaps its regional but ALL sfic I have worked on are controlled by the third pin. When I key them up, regardless of keyway, The control always moves free with any key until the 3rd pin stack is filled. Then only the control key operates it. I have literally keyed up hundreds of these sfic now and I do know what I am talking about. But like I also said in my prior post is exactly what you just said. The control key is usually completely separate from the rest of the system you created. So thanks for confirming what I said. But none the less for me the 3rd stack is what controls it every time I key it up. It is what tells the whole cylinder, "hey, grab that bar and pull it in, only go this far."

[FarmerFreak]

IndingoChild the next time you get a few minutes to cut keys and pin up a SFIC I want you to try something. Cut a change key using only two spaces, you can pick the spaces so long as you aren't using the third one. Use the depths 1, 6, and then cut a control key using the same spaces but using the depths 5, 2. Then key up a core using the bottom pins 1 and 6, buildup pins using 14 and 6, and driver pins 8 and 11.

Let us know if that works correctly for a SFIC.

[Squelchtone]

IndigoChild: Just 1 pin stack out of 6 or 7 stacks controlling the control lug sounds like really bad security or a badly designed system that you've been servicing. All 6 or 7 pin stacks should have enough build up pins and master wafers in them to have a unique control key that shares none of the same bitting cuts with any master, sub master, or end user change key.

If you look at Fig 10. in Matt Blaze's paper on SFIC, http://www.crypto.com/photos/misc/sfic/index.html you can see just how many different shearlines there are in each stack, I'm gonna go out on a limb here and say that the control key for that lock is 100% different than the operating key and not just different by the 3rd pin stack.

just my observation and personal experience,
Squelchtone