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Chastity device lock upgrades

Posted: 15 Oct 2018, 08:59
by ruru67
So I've never been really happy with the lock inserts that come on current chastity devices. Three pins doesn't seem like a lot of pick-resistance. So I wanted something a little beefier.

I found these display cabinet locks on AliExpress. They're a bit bigger than the chastity device inserts, but I figured I could do something with them. (They're about the same size as the locks found in many Chinese full belts, and might even be interchangeable, although it may require a little filing.)

Pictures (click to enlarge) are worth a bunch of words, so...
Old, new and unmodified lock inserts.
Old, new and unmodified lock inserts.
The bottom insert is the original. At the top is the new insert, unmodified (I bought two, because if I buy one I'm going to stuff it up). You can see how it's supposed to be used - the metal bush goes around a hole in one sliding panel, and the lock insert projects through, preventing the other panel from passing. Unlock and remove the insert, and the panels can slide past each other.

In the middle is the modified insert. I've just cut the thing short with a hacksaw, and filed it down to take burs off, get rid of square corners that might catch or scratch, and filed the rotating catch so it doesn't project outside the lock.

You can see five holes along the bottoms of the cylinders where the four locking pins and a retaining pin were installed during manufacture. (I think these are assembled by inserting pins from the bottom, and then inserting the lock body, finally inserting the retaining pin. The top of the retaining pin is visible, but the holes for the locking pins don't penetrate the top. This contrasts with the original locks, where the pins and springs are inserted from the top, followed by brass caps to keep it all in place. I know this, because I had one where the caps weren't seated properly, and the first time a key was inserted, all three caps popped out of their holes, followed by all the springs and pins. That one is a bit less secure than the others...)

On the actual cages the obvious modification is to drill out the hole where the inserts go. The old inserts are 6mm thick, and the holes varied a bit between 6.3 & 6.6 mm. The new inserts are about 6.7 mm, so a 7mm drill does the trick.

The top slot in the open end of the lock (attached to the ring section) needed to be opened out a little to admit the wider top flange of the insert; I did this by forcing it open a little prior to drilling, rather than by filing. That way the drilling would remove slightly less metal. The middle section of the lock (attached to the cage) just needed drilling out; the slot was already more than wide enough.

In the closed end (also attached to the ring), the slot didn't need widening, because that part of the flange is narrower and it already fitted. But the catch on the new insert turns 90 degrees, whereas on the old one it only turns 45 or so. That meant filing out the the space the catch turns into to accommodate the extra movement, otherwise it wouldn't turn far enough to lock and release the key.
Original lock insert compared to new lock insert, installed.
Original lock insert compared to new lock insert, installed.
Here we see the inserts installed. On the left is the original, on the right the new insert. You'll see that while the old insert is recessed into the lock body, the new projects slightly, mostly because the extra pin in the lock needs more space.

The unmodified ring still works with modified cage parts and the original inserts, perhaps with slightly more play. Using the original insert with modified cage and ring still works but is extremely sloppy - not recommended. With the modified parts and the new insert, the amount of play is considerably reduced compared to the unmodified parts - that may mean issues if the ring to cage spacing was a bit tight to start with. If that's the case, splaying open the section on top of the cage slightly may help. (I'm not sure, it wasn't an issue for me.)

I've drilled out all the cage parts I have, and I'll probably do the other ring. I was taking it carefully making sure I didn't ruin the best combination in the first attempt...

Tools used: power drill with 7mm metalworking bit, hacksaw, side (diagonal) cutters (for splaying, not actually cutting), mini file (needs to get into the catch space), and a small vice.

Hopefully there are enough clues in the above to do the same modification in other devices (if you care about locks as much as I do).