Brass key - unknown origin

[KHB]

I have a brass key with a hollow circular top which is roughly the shape of a cross. It has a thick tubular middle area with thinner extensions. The bladed section spins 360 degrees on a ratchet / geared mechanism. The blade has the number 6 / a on the bottom and this is repeated on the side of the key. I've had it for over thirty years and have never seen anything similar. Can anyone give me an indication re it's origins. I would have posted a picture but haven't worked out how to post one yet.

[Halflock]

How to upload images into your posts.

Here you go. Looking forward to seeing this key.

[KHB]

Unfortunately I can't get the photo's to upload. Do any of the administrators have an email address I could send them to for posting?

[BBE]

From the description I'm wondering if it isn't a watchclock key. Those typically had the number of the station where they were located on the side of the bit and when placed into the clock would actually print the location along wityh the time.
BBE.