Finally received two keys for my Multacc Real Estate Lock Box.
Decided to make a new thread instead of adding to the previous thread due to all the pictures in the first Multacc Lock Box thread.
This thread is about the measurements of the key itself, the bitting depth and spacing, and finally, about reading the punch marks on the film inside the lock that is used for logging what keys and combinations have been used to access the key stored inside the lock box.
First, here are the physical specifications from the keys.
The above picture shows the dimensions in both SAE and metric measurements. On some of the metric measurements, rounded them off to more even numbers. There is quite a bit of ‘wiggle room’ for the bitting depth.
The key part number is 432540 and is the same for both keys, so can not order specific key bitting by part number.
Here the two keys are next to each other, and the lines on the paper point to where the bittings for the five sliders are located.
If you recall from the previous writeup on the lock itself, you can see that the outsides of each combination wheel is identical, but the inside cuts are all different. They even have false gates and some false bittings, where the cuts are there and full length, but are too narrow for the slider to fit through them. Will post the next few pictures again here, so you can refresh your memory on how the lock works, helping you to understand the key better.
As you can see in the above picture, a “1” on one wheel will likely be very different in where the slider needs to be placed to fit through. So a key made with a straight line will not be like a pin tumbler lock cut to the same bitting - the combination will not be 33333 or 22222. It will more likely be 37572, 12631, 66217, or some other seemingly random combination.
Here is one of the sliders
The plug the sliders fit into is two parts.
The sliders are set to different positions by the key. The combination dials are turned to set the proper gap to the slider. This is why each key has its own combination.
This key is tip stopped, so took my measurements from the tip.
Tip to first bit:
.30” / 7.62mm
Distance between bittings:
.35” / 8.90mm
Bitting depths - these are measured/calculated from what would be the top of the key as it is inserted into the lock. There are 7 numbers that are usable on the dials, so calculated for 7 bitting depths. Numbering them 1-7 to make it easy. The second key has cuts with the exact same increment, but the lowest cut in it is .014” higher. Yet both keys work in the lock, so there must be a fair bit of play. Would assume any cut between the two numbers would work.
Bit First Key Second Key
1 .035” .049”
2 .067” .081”
3 .099” .113”
4 .131” .146”
5 .163” .177”
6 .195” .208”
7 .227” .241”
The depth of the groove is .050”, the width of the of the groove is .065”. Both keys show heavy wear from contact with keys over their lifetime of use, which made measuring a more difficult.
How to read the film audit trail. Two things to notice from the first writeup on the internal parts of the lock that punch the tape are the back of the wheels. Unlike the inside of the wheels, the pattern on the outside of each wheel is the same. So the pattern for a 1 is always the same, as with 2, 3 and so forth. In the picture below, the wheel furthest to the right is turned to 7, all the other wheels are at 1. This is so you can see how the pattern continues as the numbers progress.
And the fingers that are forced against the back of the wheels, imprinting the film. There are three fingers for each wheel, so 15 fingers total.
The pattern possibilities are therefore a combination of three cells, either with a punch or without. Will write them as a punch being “ * “, and no punch as “ . “ They work out as:
1 *..
2 .*.
3 **.
4 ..*
5 *.*
6 .**
7 …
OK, how to use the key in the lock…
1. Insert the key in the lock. The groove in the key will face away from you.
2. Turn the key so the bevelled part is flat with the keyway. (Compare this picture to the one above.)
3. Enter your code (You can enter your code before putting in your key if you like.)
4. Push in your key. It should travel in nearly to the key bow.
That releases the door part way down below.
5. Pull the door the rest of the way open. (The lock functions this way). When you fully open the door, you will hear a ‘pop’ sound as the mechanism releases, forcing the fingers onto the film, punching holes if there is not part of the wheel to block it from doing so.
If you try to use the wrong combination (here, I entered 71731 instead of 71732), the key will push in a little bit, but not nearly as much as the correct combination would allow.
If you enter a number where there is a false gate, the key will push in slightly more than without a false gate. You can use the pressure to work on manipulating the combination, but it is considerably harder when you are dealing with 5 wheels, some with no false gate, some with a false gate, and some with a true gate.
The combinations for my two keys (and the combination will only work on this box) are:
Flatter key
71732
More bitting variation key
73525
The keys did not originally have those combinations on my box. The first key I decoded had the combination of 12473. But with the other key the combination was 13322. I wanted a more difficult combination. But with the random wheel patterns, moving around 13322 would not make 31232 or 23132 or any other variation of 1-2-2-3-3. Swapping the wheels around made 73525. Then had to figure out the combination again for the first key, which ended up being 71732.
These locks were built in series, so a real estate agent in an area could have a hundred boxes where any key in that series would have the same combination. But the same key in a different series would require a different combination. This prevents someone from using a known key and combination in another town to break into houses.
There are 16,807 key permutations, each with a different combination needed with the key to open the lock box.
Each key will fit into any of the Multacc boxes, but will require a different combination if used in a series the key was not issued for. The combination is not stamped or written on the key. So if someone found a key, without the combination, it is almost useless to the finder unless they want to try all 16,807 possible combinations while trying to break into a house. That is not as easy to do as a Master combination… the key has to be pressed in at each combination - hard. The return spring is quite strong, so you will get a workout trying all combinations.
Hope this helps some of you make some keys!
Gordon
