Sattelstützklemmung - seat post clamping
seat post clamping in progress:
There might be easy ways to clamp a seat post into the seat tube. But at the end, difference is about detail and the passion for it and the passion spent into. I really like to have the bolt head fitted slick into a small tube of steel. And I like to have the slit in the seat tube (to clamp the seat post) not to cut the top edge of the seat tube, but to be fitted somewhere within...
And I really like to do good locking things with cheap stuff I find in the garage: