Also, as far as boards warping when you rip them...yep. That's gonna happen regardless of species, softwood/hardwood, or where you buy your material. Wood moves when tension is released. You do your best to stack the cards in your favor by buying high-quality, properly milled and kiln-dried lumber, but you'll still face this problem to one degree or another in every project that you endeavor. Which is why you always give yourself a little extra width when you're rough cutting your parts, and you own a jointer and a planer. Just part of the game.
Llama, Live again from the shop. If I am not here this was prerecorded live.
Tom, I was wondering if the drive had a name. The 2 halves of each pulley fit together with slots and the two halves spread apart or move together to vary the RPM. The RPM change is not real quick when I twist the control. I assume that there is something that regulates how quickly the pulleys move.
I would recommend that you rethink your project. Making a Morris chair is going to take a lot of work, so why waste it using construction lumber. No matter how carefully you choose the wood & how carefully you build, it's going to make a crappy piece of furniture that will not last long outside.
Instead, why not use that construction lumber to build some shelving for the storage room, or a workbench, or stuff for your shop. You'll gain great experience & it won't matter that it's lousy wood or that it doesn't look great.
And welcome to the forum.
Forget 2x4s if it's going outside. Find some cedar or cypress from a more reputable dealer...it should still be dirt cheap but it won't be as bad as the garbage from the box stores, and it will be rot resistant unlike the spruce/pine/fir that you build houses with.
You're not setting yourself up for a learning experience here, you're setting yourself up for a boatload of frustration, and ultimately, failure. Buy slightly better materials, your time is worth it.