Heisz wooden bar clamp

[Christophe Mineau]

Yes, thé threaded part, it's just too thick, too well guided along the bar. Imagine if you get it even thicker, you would obtain a slip fit, which is the contrary you want in a clamp.
This piece must rock a little bit in order to get locked on two points on the bar. So I would make it thinner or open a bit the square hole