How do I set up this small master keyed system?

[Werewolf]

I had a little go at this.
It's not a simple master key system at all. It's actually quite complex.
I've had to rearrange it into a system I'm used to. I renamed some of the keys to better understand what they are (BBA changed to MK and D and BA to Group Key). I've also taken B and BB as the same pinning. I left your numbering as description , so you'd better understand just how i did it.

Please keep in mind that I'm not used to keying ASSA. I've calculated this like I would a Cisa cylinder , where a 1 is the shallowest and 7 the deepest. I've kept to a MACS of 3 like you asked. And progressed in steps of 2.

I've cooked up a little speadsheet like the one i use at work. The key bitting and cylinder pinning is also in there.

[Berget]

When selecting a HLK / TMK, You should be following a couple of basic rules;
1, Must contain a 'Deepest cut' (in your system, a 1 or 2) = Provides security against a 'jump', where persons can apply turning pressure to their change key and retract their key, causing the pins to jump to the MK sheerline. Progress this chamber Second.
2, Must contain a 'Shallowest cut' (in your system, a 7 or 6) = Provides security against person filing down keys. Progress this chamber First.
3, Preference to not cut deeper than 60% of the cut series on the First chamber (in your system, a 4 or 3) = Provides a 'strong' key for the master.
4, Preferable to have 'Odd-Even' or 'Even-Odd' cuts when selecting (in some systems, may not be applicable to yours at all) = Assists in MACS for some systems, probably not applicable to yours
5, No more than 3 identical cuts (eg; 3114151 = bad code) = Just a bad idea in general
6, No Ascending or Descending cuts (eg; 124678 / 765321)

I'm unsure if MK Express will let you select a TMK / HLK, so if you'd like you can follow those rules and give me 10 codes to review, and we can see what would work best.
I can create a custom coding through promaster to provide you with codes, but now you understand how to generate an Interchange system, I'd also encourage you to knock out your own coding per lock.

Rules 5 & 6 does the current design follow. Funny thing is that alot of factory cut keys I have does systematically brake rule 5 . I've tried to comply to rules 1,2,3 but that tends to produce alot of 'pull-out-keys' (like 1,3,3,4,5). It also increases the amount of chambers and especially the amount of master wafers by a large amount. I would like to follow these rules, since it appears to be good practice and increases the security somewhat. I'm working on it
Rule nr 4 was a great tip! That proved useful.

What does TMK and HLK stands for? Top Master Key? High Low Key?

Also, in relation to narrowing down the system to avoid using X quantity of master pins; Why? Are you limited by budget / obtainability?
Security is a valid reason, and you can expand into further chambers in the future if needed - due to this being an interchange system. I would personally progress the Deepest and Shallowest chambers in the TMK code, if you're only using two chambers for the system.

Obtainability is one thing. And i find it messy to have huge amounts of masters when assembling the locks. Right now I'm actually thinking about drilling the end plugs for the chambers and thread them (Medeco-style as you might call it). Got equipment for that. That would speed up disassembling and assembling alot.

I had a little go at this.
It's not a simple master key system at all. It's actually quite complex.
I've had to rearrange it into a system I'm used to. I renamed some of the keys to better understand what they are (BBA changed to MK and D and BA to Group Key). I've also taken B and BB as the same pinning. I left your numbering as description , so you'd better understand just how i did it.

Please keep in mind that I'm not used to keying ASSA. I've calculated this like I would a Cisa cylinder , where a 1 is the shallowest and 7 the deepest. I've kept to a MACS of 3 like you asked. And progressed in steps of 2.

I've cooked up a little speadsheet like the one i use at work. The key bitting and cylinder pinning is also in there.

Thanks! Could you elaborate why you primary use the third and fifth chamber for masters? Or is it third and first? (Oh why couldn't the lock manufacturers make up their mind on a common notation?!)

I got the final map on the number of doors and keys. I also got a decent schematic on the keys and the pinning of the locks. I'm not a 100% happy with it as of now, since the master key isn't perfect and it has some odd keys. I'm working on the final setup and will post it soon.

Because of popular demand I've increased the number of locks a bit, and the included picture shows the final system. I've also removed all references to my old notation. Hope the current one follows general consensus in the industry.
Thanks again for your help, it's been helpful!

[Werewolf]

Thanks! Could you elaborate why you primary use the third and fifth chamber for masters? Or is it third and first? (Oh why couldn't the lock manufacturers make up their mind on a common notation?!

It's supposed to be the third and fifth from the bow.That is the most common notation.

The reasons for this are:
- The closer to the bow of the key , the more wear on the cylinder. I try to vary the pins at the tip of the key , to make sure the cylinder is more reliable and lasts longer.
- If you vary on 2 consecutive cuts , you will lose quite a few possible codes because of MACS constraints. By varying the 3th and 5th and setting 4th to a 4 depth , I am able to get maximum amount of permutations. That wasn't really necessary in this case , but it's ussually a good idea.

[Harvey]

- If you vary on 2 consecutive cuts , you will lose quite a few possible codes because of MACS constraints. By varying the 3th and 5th and setting 4th to a 4 depth , I am able to get maximum amount of permutations. That wasn't really necessary in this case , but it's ussually a good idea.

This man speaks truth. This can also be helpful when applied to designating chambers. For example; If you set chambers 2 & 4 for M (master keys), and 3 & 5 for C (change keys), you'll have better code progression.
eg: -GCMCM

TMK = Top Master Key (could be a 'Master Key', or a 'Grand Master', or a 'Great Grand Master', etc etc.) It's the key at the top of the system.
HLK = Highest Level Key - See TMK, same thing - different areas of the world use different references.

[xeo]

Isn't there software to generate a system for you?