I haven't yet attempted to make a tongue, let alone fit a tongue and groove together; I'd imagine making a tongue wouldn't be terribly different from making a tenon, and fitting the two would be basically like a mortise and tenon. Based on what I've seen in videos, the process would certainly be faster with a more specialized tool. That said, . . .
The making of a tonuge and a tenon or very different even though a tounge could be seen as a long or running tenon and the groove as a running mortise.
Here is an image of some blades from a Stanley #45:
Sash Blades.jpg
The lower four blades are for cutting window sash. Above are beading blades and two match or tongue cutting blades for the tongue half of a tongue & groove joint. The groove is cut with a standard plow blade.
it appears that the shoulder plane is the least likely to be frequently used in the long run whether or not it saves time on this project.
My side rabbet planes get used more often than my shoulder plane. My shoulder plane was used today, but it was to cut the fuzz off an end grain edge of a cross grain rabbet. My side rabbet planes were also put to use on the same project.
jtk
Last edited by Jim Koepke; 04-30-2019 at 11:50 PM.
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