You want a real resaw machine if you are doing manufacturing. A
regular band saw will be too finicky for making that cut in a production
way. You might want to get a horizontal resaw. At the least, you
should consider a “pineapple” feeder, which is a feeder you can
attach to a vertical bandsaw and turn it into an automated resaw.
Look on ebay for the Hitachi and Makita resaw machines. They run
3” wide blades and are the smallest and most affordable of true resaw
machines.
As an alternative, a small bandmill may be a better investment for you –
the cut will not be as nice as with a resaw machine but you can cut
lumber on the side and sell the machine for very close to what you
pay for it if the business doesn’t work out.
Look at the Woodmaster/Belsaw planer/moulders. The old
Belsaws are available used, have parts available, and are
simple machines that produce consistent boards. Any solid
iron and steel 220v planer will do what you need though.
Woodmaster has an accessory system for making tongue-and-groove
flooring but it is costly and really just a setup with the planer
in the middle and a router at each end of it. Shiplap is
considerably easier to mill and I would probably just set up
a shaper with a power feeder to do it. You can get a used
shaper with power feeder for less than $1000.
