I'm still building my hearse...as a matter of fact, I finally figured out the wheels. I don't think I could be a good tutor though because I don't have a camera...but here's what I ended up doing for my wheels
I went to Lowes and bought a sheet of plywood (the tongue and groove used for floorboard) and had them cut it in half. They were about $12.00 I also bought a gallon of TitebondII Wood Glue for about $15
Next, I bought a kinda flexible yellow metal yardstick there for about $3.00 and a 3/8" wide screw. There is a hole in the yardstick and you want to get a screw with a snug fit to go in that hole.
When I got home I glued the halves of the floorboard together. I put the glue on the rough side and stacked them on top of each other then put a bunch of heavy crap in the garage on them to make sure they were glued tightly together.
Next comes the fun part and requires you to remember some math.
I made two size wheels (46" and 36") I didn't go 48" on the large one because I didn't want to deal with the edge of the board. I found the center of the plywood and drilled a starter hole for my 3/8" wide screw. Then I screwed the yardstick to the plywood using the hole that was already in the yardstick. That hole is about 3/4" into the yardsick, so remember to add 3/4" to all your measurements. So for the 46" wheel, I used a punch and put a hole in the yardstick at the 23 3/4" point. I then took an awl...something strong and pointy to sitck in the hole I punched) and just scratched the circle into the plywood....it came out perfect. I wanted the 46" wheel to come in 4" before I got to the spokes, so I marked the 19 3/4" spot on the yardstick, punched it and traced that circle on too. Then I used a jigsaw to cut out the outer circle...ONLY the outer circle.
For the next steps I used a long level I have that's 5ft long, a framing square to make 90 degree angles, a protractor and the yardstick I bought at Lowes since it's flexible.
Using the long level, draw a line across the wheel...as long as it goes over the screw hole, you're good. Now using the framing square, to get the 90 degree angle, butt the long level up against it and draw the line through the center so you have four of your spokes laid out. If you have a protractor, draw a 45 degree angle out from center, if not, wrap the flexible yardstick around the outer edge and measure the distance between where the two 90 points are..divide the distance in half and mark that point, then draw a line through center all the way across the wheel, then draw the line perpendicular to that one using the framing square. Now you have 8 spokes. Measure/mark the halfway point between the spokes on the outer rim and draw the lines through center... and viola, you have 16 spoked on your 46" wheel.
Screw the yardstick back on the wheel, then if you look at the edge of the wheel and lay the yardstick centered on the line you drew for each spoke, you can trace both sides of the yard stick out to the inner circle that was marked earlier....just go around the wheel until all your spokes are traced out. I used a big marker when laying out my lines so that I would be able to see it through the dust the jigsaw creates. After the spokes were traced out, I marked the innercircle on the cut line, between the spokes to ensure that I knew where not to cut so that I didn't accidentially chop off a spoke.
Next I looked at where the spokes all came together at the hub to figured out how big I wanted my hub to be based on the intersection points, then I punched a hole in the yardstick and traced that line. I think I had about a 7" diameter on my hub. Eyeball it and choose what looks best to you.
Then, the fun part, cutting out all those wedges... with a steady hand, you'll kick out and awesome wheel. I don't have a steady hand and the wheels not perfectly round, nor are the spokes straight, but the wheel look great
For the 36" wheels, I measured out on the yardstick to 18 3/4" for the outer rim, 15 3/4" for the inner circle and then only had 12 spokes. To get your 12 spoke, layout your two 90 degree lines like you started with the big wheel, then measure between the 90s on the outer rim and divide by 3. I think I measured 28" so it was roughly 9 3/8"s between the spokes, so I marked the wheel at 9 3/8" and 18 3/4" and drew the corresponding lines through center. Then it's the same procedure as above. I think I ended up with around a 5" hub on the 36" wheels.
I'm not a perfect jigsaw cutter, but I really like the way the wheels turned out. By doubling up the plywood, I have some pretty sturdy wheels. I'm not going to wheels for weight bearing, but I'm thinking they probably to stand up to a bit of weight. I'm debating on rounding over the spokes with a router, but I really dont think it matters.
bottom line, about $65-70 to make all the wheels, which is cheaper than Harbor Freight, plus I got the bigger 46" wheels in the process. And if you only go one deep on the plywood, you can cut our all four wheels for about $25 since you won't need the glue or 1/2 the plywood.
Glue the boards and let them sit overnight then count on dedicating a day to cutting out the wheels if you're going to try it.