I can't imagine how much force you can get from simply pushing it. It seems unfathomable, but so did the use of a demi-bisaiguë until I got my hands on one. The idea (as described in the book I quoted from before) is that your left hand sits on the shaft and guides, while your right pushes against the "handle". There's a relatively local association that explores traditional carpentry techniques. I'll try and get in touch with them and see if they can shed some light on the matter.

It is true that traditional French carpentry tools are one-piece metal affairs. The old joke played on the new apprentice was apparently to send him off to look for the wooden handle for the bisaiguë. This practical joke appears to be better known than how to use the tool itself. You can read into that what you will.