My bad. You’re probably correct considering its been 8 years since I’ve cut any keys. But i did have about a decade and a half of key cutting experience. I used to be able to cut 3 keys at a time if the chuck would open wide enough mostly just with the wr-1/kw-1/ar-1 and sc-1 blanks. I don’t miss finding those damn brass shards in my feet after work though

I did clarify in another comment that it did look like an assa key after this comment. Sometimes those little round keys for special cylinder locks and po boxes were the hardest to figure out.

Looks like one of those assa a-xx high security commercial keys with extra slots, some of them even have stepped slots for additional pins in the cylinder.

I guess you could copy a key from a picture but it would be a real pain.

Oh so the replacement isnt the little round y-1/m1 blank in the left side of the pic? Ive cut a lot of keys in my day and what makes them work besides the jagged pattern the pins fall into which allows the lock cylinder to turn are tbe pattern of groces along the horizontal shaft of the key. Sometimes other blanks will work if the slots are not to specific and the key slots are just vague/thin enough to fit into the cylinder but these 2 key blanks have very different slotting configurations

Thats not the right keyblank…… the broken one looks like an sc1 or a y-11 and the little one looks like a y-1/m-1 for master locks.