Tongue and groove joints can easily be made with a router when using the right bits on a proper router table.
Make my own tongue and groove siding.
Check to make sure the siding you choose has a successful track record in your region.
Calculate sqft to lft coverage needed vertical siding applications require horizontal nailers blocking or other wood framing members spaced no more than 24 inches on center.
Other types require face nailing as well.
To begin making tongue and groove boards you first must decide to use either a table saw or a router.
Depending on how the pieces fit together some jointed sidings can be fully attached by blind nailing through a tongue or underlap that will be covered by the course above.
You can use your circular saw set to the depth of just the back part of the groove.
Make sure your routing table is clear of sawdust and other debris.
Carefully slice the back part of the groove of your replacement board but leave the front part of the groove attached.