DIY Pannier locking system
 

Attached is my idea of a simple-to-make method for attaching your panniers to the racks using an external latch.
It uses a basic 'L' shaped latch which is fitted onto the panniers immediately above the top of the rack frame (shown in GREEN on the image) and a short piece of angle bar which is fitted to the LID of the panniers (shown in BLUE).

The panniers are carried to the bike with the latch in the OPEN position and located onto the frame.
Then OPEN (or remove) the lid and rotate the LATCH to lock the panniers onto the frame.
When the lid closed (or replaced), the angle bar (in BLUE) prevents the latch (in GREEN) from being opened.
What's the advantage of this over other systems?
1) - SECURE!
2) - Speed! Opening the lid and rotating the latch is a 10 second operation.
3) - No additional keys or external locks required.
4) - No need to remove anything from inside the panniers to get to the mechanism (unlike other systems).
5) - Simple to make at home.

For anybody thinking of making their own racks or panniers, I think this is an easy to make idea.
The blocks I've shown for locating the panniers could be made from a block of nylon or (more probably easier to find) small blocks of hardwood.
The latch and the angle bar......I'm making from aluminium. To stop the latch scraping any paint from the rack, use some heat-shrink sleeving (the sort you'd normally put onto electrical cabling). This can easily be replaced and renewed as and when necessary.

I'm making my own racks using 25mm x 12mm flat-sided-oval (racetrack) tubing because it's strong, gives a nice flat area for the panniers to fit to, and looks better than bare round tube when the panniers aren't fitted.

I've drawn this using AutoCAD draughting software. I'm happy to give anybody a copy......just ask.

Any suggestions for improvements would be welcomed.