Creating a sub key

[Lbchicano]

I’ve taught myself how to rekey door locks and pad locks, so far I’ve done well. Still trying to grasp how to do master keying. Currently I have a 5 pin master key with a bidding of 74757 is it possible to make a 4 pin sub key work? The sub key has a bidding of 9697.

[RedStagKiller]

Your terminology might be off, I assume you are looking to make the 4 pin key a "change" key, or at the very least you are just wanting both keys to work the lock? Yes you can do that with those bittings. First you will need to remove the top pin and spring from the housing and also remove it from the plug. Then just pin up the first four chambers as so.
Master pins 2 2 2 2
Bottom pins 7 4 7 5

[demux]

I'm afraid you're going to need to clarify the question. If you're talking about making a key with only 4 cuts work in a 5 pin system, that is highly unlikely (theoretically possible if one of the cuts is 0 but not likely since most key blanks are factory milled just a hair higher than 0 so you can fine tune the cut).

So I'm going to assume your proposed submaster key is either X9697 or 9697X where X is some other cut. In either case you'd need to state what key system you're using because the parameters vary, but seeing that you have a 9 cut mentioned I'm going to assume it's a two step system as most of the single step systems do not go that deep. If that's the case, option 1 above would not work as you have an even cut in position 2 on one key and an odd cut in position 2 on your proposed submaster. The second case could work at long as the last position is also an odd number. In that case you'd have a number 2 master wafer in the locks in the first 4 positions, and depending on what the final X was would determine what (if any) master wafer you had in position 4. Since you said you're looking to make a submaster key instead of change key, I'll assume the last cut would be a 7, making your submaster key bitting 96977. This key would open any locks under the TMK whose pinning begins with 9697. Specifically, 96971, 96973, 96975, 96979.

[Lbchicano]

Than you for the replies. I haven’t mastered the terminology yet. I left out some information, So what I’m trying to accomplish it to see if it’s possible to open the same lock with with three keys. Currently the master key works 74757 and sub key 1 that works 96979. I would like to see I using sub key 2 would open the lock as well, which is a 4 pin 9697. This is for a Abus 8345 lock. I hope this explanation is more clear. Thank you

[RedStagKiller]

Than you for the replies. I haven’t mastered the terminology yet. I left out some information, So what I’m trying to accomplish it to see if it’s possible to open the same lock with with three keys. Currently the master key works 74757 and sub key 1 that works 96979. I would like to see I using sub key 2 would open the lock as well, which is a 4 pin 9697. This is for a Abus 8345 lock. I hope this explanation is more clear. Thank you

Is the 4 pin key the same length as the other two keys?

[Lbchicano]

Yes all 3 keys are the same length

[RedStagKiller]

Yes all 3 keys are the same length

Then odds are your 1st or last cut is a zero, probably the first (Like Demux was Saying). Ive never keyed an Abus (I usually only key commercial locks) so someone else knows more than me and can help better answer you. I would say you could pin it to all 3 keys but you are going to make it a little unsecure in the process because youll have to use multiple master pins per cut and youll have to drop a chamber (if Abus doesnt allow a 1 master pin).

[Lbchicano]

Yes the last cut on the sub 2 is a 0.

[Squelchtone]

As you work on mastering master keying terminology, I wanted to let you know that while your user of master key is correct, what you call a sub key is normally called a change key, and for the cuts of a key we say bitting instead of bidding. You *could* call a key a "sub master" in certain situations, but that is more for a very large system, like a college campus or business office complex, where 1 grand master opens the entire campus, the sub masters are set to open an entire building, or an entire floor, etc, and so on, down to the change key which usually unlocks only one door lock.

[GWiens2001]

Don’t forget that for each pin stack to which you add a master wafer, you double the number of working keys, and halve the difficulty in picking it.

In other words:
No master wafers = 1 working key.
1 pin stack with a master wafer = 2 keys that will work the lock.
2 stacks with one master wafer each = 4 working keys
3 stacks with one master wafer each = 8 working keys
4 stacks with one wafer each = 16 working keys
5 stacks with one wafer each = 32 keys that will work the lock.
Note that this applies to locks with one shear line.

One of the best sayings that I have heard about master keying is:

“Master keying is the controller destruction of security.”

If you want two keys to work, with minimal impact on security, add one wafer and change one of the keys respectively.

Gordon

[demux]

So if I understand this right, you have a lock that is currently operated by master key 74757 and change key 96979 (note in this case this second key is called a change key, not a sub master, as it has no cuts the same as the master key) that you would like to also be opened by a key with bitting 96970. Correct?

If that's the case, what you're doing may be possible, though perhaps not advisable. What you're doing in this case is called cross keying. It's when a lock is operated by more than one change key in a system. There's nothing inherently wrong with this, but as Gordon pointed out it does reduce system security by introducing one or more ghost keys (keys that are not technically part of the master system according to the key bitting array but that still work). If done with restraint and pre-planning the effects can be mitigated, but if done rampantly and without thought it can dramatically reduce the security and shorten the lift of your master system. I would consider this an advanced master key topic and should really only be attempted if you fully understand what you're doing.

In this specific example, you would have a number 2 master wafer in each of the chambers in your lock, as both RedStagKiller and I have already pointed out. In addition, you would also have a number 7 master wafer in the last chamber. However, if your key system is a two step progression system, this would violate the parity in the last chamber and you may not even be able to get a number 7 master wafer. Violating parity in a two step system can lead to unintended key interchange. In this case I would go back and see if the last cut on your second change key is actually supposed to be a 1 not a 0.

[GWiens2001]

I would consider this an advanced master key topic and should really only be attempted if you fully understand what you're doing.

+1

Gordon

[cledry]

Just based on the two keys that work the lock you could just cut one of the ghost keys and have that also work the lock. You have many to choose from already without any additional pinning which would add even more ghost keys.

[GWiens2001]

Just based on the two keys that work the lock you could just cut one of the ghost keys and have that also work the lock. You have many to choose from already without any additional pinning which would add even more ghost keys.

The lock currently has only one working key. The OP wants to add interoperability of the second key to the lock.

Gordon

[demux]

Just based on the two keys that work the lock you could just cut one of the ghost keys and have that also work the lock.

I know Jim knows this, but for anyone reading this thread in the future, be very careful when cutting keys outside the key bitting array. It's a valid and useful technique if you know what you're doing, but make sure you fully understand all the locks that such keys may open before issuing them. It may be more than you think. Hint: if you're not familiar with terms like row master, column master, and what the math behind those means, you probably shouldn't attempt this.