Great little mod, Stamp. I especially like the idea of keeping the handle vertical and away from the fire.
Permit me to present the MkII version...
The MkII resolves the issue with the spikey bits sticking out and catching on the bag. Instead, the ends of the wire go into the little holes at the side. Here, it's at its lowest point - this is what would stick out if it was in the down position. Might catch a bit on a tight stuff sack, but no snagging.
Here's the lock in the up position. There is no friction here, just gravity - a little tilt of the billy will result in the lock swinging back down.
The bail on its way up. The bail can come up easily whether the lock is up or down. If the lock is down, the bail just lifts it into the up position as it passes.
Now the bail is fully vertical and the lock has fallen into the locked position. It doesn't always do this, but, as above, a little tilt of the billy will move it over. In fact, when locked, a little tilt the other way will unlock it.
Here it is with the everything lying horizontal. Just tried it with the billy full of water, and it held just fine. Once there's weight on it with the bail pressing against the lock, the tilt-to-lock and tilt-to-unlock doesn't happen - it stays locked.
Design notes...
The short bits need to be sized so that the bail can pass easily when the lock is in the up position. At the same time, they need to be long enough to get the 'corners' to protrude past the bail to get the locking action to work. To get the best of both these, don't make it too high (too long from the holes it goes into, to where it bends at the short bits). In the above, the 'cross member' bit just fits under the rolled edge on the rim of the billy, and that helps to maximise how much the corners protrude when locked.
The bits inside the holes are about 3mm long, and pliers were needed to ease the second end past the side of the the top-hat section to the hole.
If you fit two on a billy, you will lose the tilt-to-lock and tilt-to-unlock action, because each tilt will try to lock one side while trying to unlock the other side. On the other hand, because it can unlock with a little tilt, the billy should not be set in a fire with a bit of tilt in the wrong direction - the handle won't stay up, and you'll be reaching for a stick to sort things out. If you require manual intervention to unlock, fit two.
The wire is standard-issue coat hanger, and it's a 10cm Zebra.
nttern it before they do.
