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Reverse Key Blanks | Locksmithing 101

Have you ever been looking for a key and the closest thing you could find was the exact opposite of what you're looking for? It's kind of common in the world today because there is a ton of keys. Here’s how to find what you're looking for.

When it comes to key blanks, especially in the aftermarket world, a lot of times, we're given some random key that we need to find, and it's almost like looking for a needle in a haystack. However, there are a lot of nuances when it comes to the key blank part numbers, so today let’s go over six examples of reverses. You'll be armed with the information and understanding of the nuances with the key blanks that you'll be able to find what you're looking for.


A lot of the part numbers are the commonly known part numbers for the key. Also, the Ilco part numbers will be included because Ilco in the US is the standard part number system.


1646 the very popular mailbox key. The Ilco part number is 1646R; R stands for Reverse. When trying to find the opposite key, the best thing to do is find that part number and see if there is an available option that has an R at the end.



The Bauer key blank has two different sets of part numbers that are commonly known. The first is the 1618 and a 1618R. R for Reverse. It's also known as the BAU1 and the BAU1R.



A lot of times for key blanks, they're not quite that easy. The popular one is the M1, a Master padlock key. In some other places, it’s called as the M1R key for simplicity's sake, but it's more known as the M15 key. So, if you have M1 and need the reverse, it's going to be called the M15. You might be lucky and find it as the M1R. But once again, if we look at the root of it, you're going to see it's the M1 Ilco part number 1092 and the M1R or the M15 is the 1092R.

So, if we take the part number, we know it as the M1 and maybe we're not finding that M1 reverse easily. Find the Ilco part number (1092) and look for an R of that.



Another super popular key is a Y11. The reverse of a Y11 is a Y13. It may be hard to guess; it’d be nice if it was a Y11R. It's not going to be hard if you look at the original Ilco part number for it. You'll find that the Y11 part number is O1122 and the reverse of that, the Y13, is going to be an O1122R. Going to the most known number and tracing it back to the Ilco part number can help us determine what is the reverse and what isn’t.



Another popular key is kind of the same thing but a little different. It’s the CO106. It is a very popular mailbox key and the reverse of it, unfortunately, is not CO106R. It's BO1. Checking the original part number of the CO106, the Ilco part number is 1003m. While the BO1, the reverse of the CO106, the Ilco original part number is R1003m. They put the R in the front instead of the back.



Everything that has been discussed above will be a little different with the Larsen Door key. The part number commonly known is the LD1. The reverse of the LD1 is not the LD1R, it is LD2. So, if we check the Ilco root or the main Ilco part number, we find that LD1 is 1639, and the part number for the LD2 is a 1640. They don't have the R at the end. Kind of the nuance of the part numbers.


Taking the time and starting to understand this information will put you in a spot where you’ll always go back to the root and see if you can find the reverse that way. I hope that this will help you look up the reverse of a key.

I want to know your thoughts in the comments or if you have any other ones that break the rules a little bit. Let's look and talk about them.

Thank you for watching, and we'll see you next time.

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