My bag/rack exploration sort of stopped for quite a few years about now, after the Madden bag racks. Loosing a wife, moving back to the home town, taking care of elder parents, buying and later selling houses and getting use to the 4 seasons of my growing up all took their tolls.
To mimic this slow period this post has some shots of previous rack making and a shot of the clamping bolt barrels I have made/used.

This is one of the racks for the Madden bags. Once the "jig" was established and the rack/post clamp geometry understood it wasn't too hard to do the rest. The post clamp tube has the second bike's rack binder bolts (the M5 ones contracted out) in place already.

Here's a seed for the next design family. Made for Earl Y, a member of the CR list. He wanted a vertical support for his Eclipse bag which could be easily removed. While I think this achieved that I wasn't happy with it for my needs.

Some binder bolt barrels. Top is a common M6 bolt type, available from a few suppliers in one form or another. Middle is a self designed and contracted out fabrication M5 version. While I do like this, being about 85% as large as the M6 one, it is still a bit bulky for some applications. Bottom is what I might call an "in line" M5 version. Much less bulky than the middle and better for binders that are on the sides of post clamps. These are home made.
Next will be where this thread started, Andy