Bandsaw notching.

[HughF]

My friend has a manual crop notcher, it's bloody fantastic but you do need your wheetabix if doing scaff tube.

 

[zeppelin builder]

Here is a simple method,get your self a diamond stone dressing tool and profile the grindstone on the bench grinder lay the tube in a v rest and simply push it on the stone it works well on thin tube, we built a fuselage for my mates zero design stunt plane all prepped like this some of the tubing crmo was only 40 thou thick so had to be perfect fit up and pulse tigged

 

[Richard.]

Here is a simple method,get your self a diamond stone dressing tool and profile the grindstone on the bench grinder lay the tube in a v rest and simply push it on the stone it works well on thin tube, we built a fuselage for my mates zero design stunt plane all prepped like this some of the tubing crmo was only 40 thou thick so had to be perfect fit up and pulse tigged

This is a decent way to get a nice fitting notch but only useful if you've got either loads of one size to do or if you've profiled plenty of stones for different tube diameters.
It's a neat idea though pretty much the same way an abrasive notcher works.