violate MAC for Arrow

[dontlook]

I learned about MAC(maximum allowable cut) rules very briefly. We are starting to have trouble with one of our keys and I looked at and it looks like at the beginning of the key there are some extremely opposite cuts.

Does anyone know where I might find arrow MAC information for Arrow cylinders?

[Raymond]

The key you have displayed may be manufactured by "Arrow" but since it is a "Small Format Interchangeable Core" (SFIC) the MACs, Maximum Adjacent Cut, do not apply. The MACs only apply to standard pin tumbler type locks. SFIC keys and locks work very well using 0909090 extreme combinations.

[Squelchtone]

Hi dontlook!

Good to finally see you here! =)

see you at the next locksport meeting,
Squelchtone

[dontlook]

Thanks Raymond.

Hello Squelchtone. Thanks for the welcome.

[Jeremym0411]

Mac for arrow is 7. If you have a lab pinning kit you can only on there for the mac for all the different key ways.

[cledry]

Mac for arrow is 7. If you have a lab pinning kit you can only on there for the mac for all the different key ways.

Not for SFIC though.

[Teddy Picker]

The key you have displayed may be manufactured by "Arrow" but since it is a "Small Format Interchangeable Core" (SFIC) the MACs, Maximum Adjacent Cut, do not apply. The MACs only apply to standard pin tumbler type locks. SFIC keys and locks work very well using 0909090 extreme combinations.

I'm curious; could you explain why this is? My understanding is that MACs are there to create a maximum angle between cuts. Like, the angle between the cuts is a ramp: if the ramp is too steep, there will be too much friction and the key won't slide smoothly in/out of the lock. What is it about the SFIC design that allows the steeper cuts?

[cledry]

The key you have displayed may be manufactured by "Arrow" but since it is a "Small Format Interchangeable Core" (SFIC) the MACs, Maximum Adjacent Cut, do not apply. The MACs only apply to standard pin tumbler type locks. SFIC keys and locks work very well using 0909090 extreme combinations.

I'm curious; could you explain why this is? My understanding is that MACs are there to create a maximum angle between cuts. Like, the angle between the cuts is a ramp: if the ramp is too steep, there will be too much friction and the key won't slide smoothly in/out of the lock. What is it about the SFIC design that allows the steeper cuts?

The angle doesn't change unless you change the cutter. MACs is so that your shallow cut doesn't disappear entirely. If your system uses a cutter with a steeper angle you can often cheat on the MACs a little. The angle will be a bit steeper but you will not intrude on an adjacent shallow cut.

[Raymond]

I am not sure if there is a specific formuls for calculating the MACS for a specific lock system or not. The application is variable. Some keys work well with a 37 degree cutter and others must have a 45 degree angle. Also, on SFIC, Best A2 systems, the steps from one depth to another is .012". The plug is smaller but the pins are still far enough apart that there is no problem. The step on Schlage is .015", Yale - .019, Sargent - .020, Kwikset - .023". So you can see that there is a lot of variation in the design. The wider diameter pins, .115", on standard locks compared to the those on SFIC, .110", also play a role in the calculation.

I have done at least one master key system using Yale for example where I set the cut drop to .015. This actually allowed cuts from 0 to 11, 12 actual depths. I used 2-step progression and the MACS had no effect at 8. (It was a big system.)

Each lock manufacturer engineers their lock to meet their own standards according to their marketing strategy. If they want their key to be interchangeable with others they can sell more replacement cylinders. If they want to be unique, nothing will be interchangeable.