I just posted this on Traditonal Tools Site.
FWIW on taper locks.
I use round taper locks as they are a lot easier to make and work with, but this theory works with square or rectanguler taper locks also.
This is one of my Depth gauges that uses a taper lock.
And this is a pair of African Walnut Dividers that uses the same thing to lock it in position.
This is a basic drawing of the principle.
The trick is to drill the holes so they overlap just a tad. And a long slight taper works better than a short steep taper as it has a lot more holding power because it wedges easier and tighter. The tapered wedge is captive so it can't come out unless you remove what it is holding in first.
Just thumb pressure is all that is needed to positively lock it, and finger pressure on the other end will release it easily.
Red dashed line is the drilled hole, Green is the wedge, black is the captive bar. Gray is the housing.
I make my own dowels from native woods, but a common hardware store dowel will work just as well and you can stain it any color you want.
I hope this helps someone