Hi all!
Ok, so, I'm done! Thanks again to everyone that helped with this. I've attached pics.
A few quick notes for anyone else that may have this issue:
Total tools: Circular saw, Speed square, clamps X6, sawhorses (hand-built from cheap pine), the jigsaw for one difficult cut, drill (I think it was with the 3/8 bit, but check before using), nails (8d finishing), a nail set (to set the nails under the height of the board), and a hammer. I also used a pair of pliers to bend nails and break them out the board when they bent.
Tips:
- When matching color, make sure you pick an AVERAGE board for your floor. I picked one that was a bit too dark, and it shows in natural light. The floor has to be refinished anyway so it doesn't matter as much to me, but it's still annoying.
- A speed square (or guide of some sort) is your best friend. I clamped it in place and used it to keep my lines straight for my cuts. This really only mattered for the short cut across the board.
- For the most part I could leave the tongue on the boards and just remove the bottom flange of the groove and slot it into place. I wedged some into place by putting a piece of scrap lumber against the board and tapping it with a hammer.
- Most of my replacement boards have less than a credit card's width gap on both sides. I'm okay with that. It's not noticeable when you look at the floor.
- Diagonal nailing without a nailgun sucks. I gave up and face-nailed.
- Predrill holes before nailing or your life will be difficult.
- I fit one board at a time, but I made sure the next board would work before I nailed the previous one.
- Test fit. Test fit again. Then nail. :) You may need to wedge while nailing because the board may move.
- If you can, test your technique on some sacrificial lumber before you start so that you have a feel for how things will work on the actual floor. Prying up boards to re-nail things is troublesome.
- The final board in the patch (at least for me) had to have both the tongue and groove removed before it would fit. Your experience may differ.
GIVE YOURSELF PLENTY OF TIME. Something always goes wrong... in my case, I found that the tongues went opposite ways on either side of the patch for the right hole. That was fun. Luckily, the floor is made up of primarily short boards (all around 18 inches, give or take) I ended up patching by removing the tongue on the exposed board and tapping it into place on one side, then sawing the tongue off the other board in the next row and slotting/tapping into place. This meant that the tongue sides of both boards could meet with no issues and I didn't have to pry up more floor than necessary.
I also ended up shimming some scrap from my cuts under parts of the boards (less than 1/8 of an inch). My floor had settled in places and the boards would bend as I stepped on them, or flex when I nailed them. I've since learned it's probably better to do this underneath at the joist if you can, but my basement is finished. If you have any recs on how to do this part better, please post.
I haven't puttied the holes yet--trying to figure out what color to refinish the floor. My understanding is that the putty doesn't stain as well as the floor, so I want to get something close to the final floor color.
All in all, fun and challenging. Thanks everyone for your help! I've picked up a new skill. Pics below.
Final edit: Total time for the bigger hole (I called it the left one, but it's the right one in the pictures) -- 12 hours as I learned what the heck to do. Total time for the right hole (with the opposite-facing tongues): 4 hours.
Sorry for the multiple edits (if you actually see them).