There are never enough cup holders. You have your coffee, water bottles, 1 liter seltzer bottles; Not counting the half drunken ones that you forgot to throw out... Here's a super easy wood project to add 8 cup holders to your car.
Step 1: The BOM
This whole project took less than 2 hours, I made it out of some left over 1x12 and 1x3 boards I had laying around, and some 1 5/8 deck screws and some glue. Oh, as I made the top of the cup holder very high over the hump in the back seat, I used some black styrofoam packing blocks as spacers.
Step 2: Construction
so what are we talking about here?
1) I measured the width height and depth of the hump in the back seat of the car with the seats pushed back, In my case that resulted in an area of 24 inches by 8 inches. the hump was about 3 inches, high and I build the side supports 8 inches high to give a lot of room for the 1 liter bottles, and tall water bottles, figuring I could put something underneath to raise the cup level for shorter cups.
2) I drew the holes on the top, drilled some holes on the line, and then cut the ciricles out with a scroll saw.
3) the router was then used to round off the inside edges (you could just file them) and I set the router bit higher to ge that nice box out section for the outside edges of the top.
4) screw and glued the edges together.
5) coat of stain, and then a 50/50 mix of teak oil and poly-urathane to seal in all the stain.
Step 3: Final Fit.
After everything was dry, I stuffed underneath with a filler material (in my case black styro-foam, but floaty noodles, tissue box, old rolled up towel, etc will do.) As I MEASURED TWICE AND CUT ONCE. all fit exactly in my back seat perfectly. the passenger seat pushed all the way back even double as a lockdown on the cup holder.
Step 4: Final Photos Installed.
Wife is thrilled. Now she can keep 8 cups of half-finished old coffee and soda bottles without spilling any of it!!!!