Corbin-Russwin LFIC Control?

[Raymond]

Due to lack of opportunity and experience I am not fluent in working with Corbin-Russwin large format removable cores. I was able to get a core out of a lock and measure the pins. The client states they do have a master key-change key set up but have no core key. The keyway is CO88. The core is the type with the center four pins turning the control sleeve. From the pin measurements below can someone deduce the most likely control key cuts? The change key was exactly the bottom pins only. I am not even sure which Corbin series to use with our code cutter.
Do you know the exact height of the control lug at the pin location? The plug is a standard .5”


Spaces (Bow to tip)
1 2 3 4 5 6

Wafers (inch)
.052 .133 .032 .131 .131 .017

Bottom pins
.205 .196 .236 .196 .237 .240

[jeffmoss26]

you need to measure the top most pins in chambers 2-3-4-5

[Raymond]

Unfortunately they were scrambled. If I knew the height of the control lug I think I could calculate the control key depths.

[RedE]

Would you be able to measure the cuts of the keys? The reason I'm asking is that the posted pin measurements are noticeably off compared to standard sizes for your lock. Perhaps this is because the lock was not pinned using factory specs, or maybe is extremely worn?

Also, the height of the control lug is 0.163"

[Raymond]

This lock was pinned so all bottom pins were the change key. I also compared the pin lengths and the cut key to the ITL book and could not guess which series of depths would apply. With the control lug height known, I might be able to extrapolate (yeah guess) the control height.

Plug diameter, .5", plus .163", minus bottom pin plus wafer should yield control key depth if I guess the right correction for the depth cut. Perhaps I can just use the closest higher number and impression down.

Thanks for your assistance.

[GWiens2001]

Spaces (Bow to tip)
1 2 3 4 5 6

Wafers (inch)
.052 .133 .032 .131 .131 .017

Bottom pins
.205 .196 .236 .196 .237 .240

Have you verified the calibration of your measuring caliper? Cheap calipers can be surprisingly far off accuracy, and differences of only a few thousandths can really change which class of keys and which system are used.

The plug diameter is actually .509" for all conventional CR IC cores. There should also be build-up pins in the center four chambers (there can be very rare exceptions). Keep in mind that there are 11 different Corbin and Russwin bitting specifications, each of which use their own pin sizes. And that is after the consolidation of the pin sets done in the early 1990's.

If it really is a Corbin core, Is the bottom of the key radiused (curved) or flat? Radiused bottom of the blank is an X Class, flat is Z Class.

All System 70 (current) Corbin Russwin series use 6 depths with a .028" increment. Pre System 70 Corbin systems use 10 depths with a .014" increment.

Even with all that taken into consideration, the pin lengths that you listed do not completely line up with any of the 11 different sets of pins. Hence my inquiry as to the accuracy of your caliper.

If the last wafer in your listing above is correct, it is too short to be System 70 (.028" increment), but too long to be Pre-System 70 (.014" increment). An experienced locksmith would know that it is a bad idea to use a 1 step increment with that short (.017") a wafer.

Good luck,

Gordon

[Raymond]

Hey Gwiens2001
I agree with everything you said. My caliper is a Mitutoyo mechanical and verified with a Centec electronic. It has never given questionable readings.

I did not check the plug diameter as my .502 plug follower worked fine even when working with that silly .017 wafer. I did not realize the diameter was .509.

All of the keys I saw or used have the flat bottoms because none are factory originals.

[*Even with all that taken into consideration, the pin lengths that you listed do not completely line up with any of the 11 different sets of pins. Hence my inquiry as to the accuracy of your caliper.]
Yeah!!! This is why I tossed this question to everyone for help. I don't know who pinned it before but I know it looks screwy.

I will factor in the different plug diameter and still try extrapolating the control cuts. I might use a Framon or HPC code cutter because they are good when working with mutant systems.

Thanks to everyone.

[Evan]

Due to lack of opportunity and experience I am not fluent in working with Corbin-Russwin large format removable cores. I was able to get a core out of a lock and measure the pins. The client states they do have a master key-change key set up but have no core key. The keyway is CO88. The core is the type with the center four pins turning the control sleeve. From the pin measurements below can someone deduce the most likely control key cuts? The change key was exactly the bottom pins only. I am not even sure which Corbin series to use with our code cutter.
Do you know the exact height of the control lug at the pin location? The plug is a standard .5”


Spaces (Bow to tip)
1 2 3 4 5 6

Wafers (inch)
.052 .133 .032 .131 .131 .017

Bottom pins
.205 .196 .236 .196 .237 .240

So your issue is that you only measured two pins in each chamber. In the control chambers there are 4 pins total and 3 pins in each non-control chamber. Second this was a system that was created by someone in the field, it is not factory.

Your keyway is 60 and it is 6-pin. CO88 = Z-60-6 (Z-class) (keyway 60) (6-pin)

The 3rd pin up in the control stack is the magical one, it in relationship to the stack below it determines the control cut. Build up pins can be 0 (same) bitting as below (0.163) or add (+) to or subtract (-) from the stack height below. The 4th pin in the control chambers is a master wafer corresponding to the valve of the control key in that position. The problem here is that the pin sizes you describe are not System 70 or Pre-System 70 even trying to factor in a bit of wear. Someone made this work with non-factory keys a non-factory pins.

Factory Rules for Conventional LFIC Cores:

1. The control key bitting must be identical to the TMK except in two positions.
2. The two positions which are different must fall within the range of positions 2 through 4, because those are control chambers.
3. Specifies that High Security ICs must use chambers 2 and 3 as the control chambers.
4. The two bittings which make the control key different must not be used in the progression of the system.
5. In System 70, do not use a #1 cut in the control positions of the control key. No build up pin is available to use a #6 cut to operate under it.

The above comes from Page 31 of the CR Keying Manual.

I think your best bet to determine the control key is to measure all the keys you can gain access to and knowing the rules find the two missing cuts in the two control chambers used in your system. If you have access to the master key and all of the change keys you will see a pattern of cuts that are missing from the system in 2 of the 4 control chamber positions. Those missing cuts are your control cuts in those chambers.

~~ Evan

[Raymond]

Thanks Evan for the additional info. I have read the manual but having nothing to work with just do not remember all the details. I never did completely understand the +1, -1, +2, etc. without a factory pin kit.

I agree that this was a bastardized set up. I only had to rekey one lock so I did about the same and just made something that would work. What I did is still more secure as it is not on the grand master. Spaces 1 and 6 are straight pinned, one bottom and one top. Spaces 2,3,4,&5 have one bottom, one build up, and one top pin. (all random numbers but using CO-88 depth keys.)

Water under the bridge until next time.