I've built 2. Here is a materials list. If I have chance, I'll set it up and take some pics and post it here.
1) boat crank or small winch with rope
1) carabiner clip
1) 2x6 6'
1) 2x4 4'
1) 1" pipe floor flange
1) 1" gal. threaded nipple fitting 6" long
1) 1 1/4" plastic tubing to cover 6" nipple or thin foam and duct tape.
You will need to decide if you want to mount this on the wall or make it portable. I had to make mine portable, so I used my Skill portable folding vice bench for the drawboard. I've seen some mounded on the wall horizontally, and some mounted vertically. Here is what I did for a portable draw board. My board sits horizontally when in use, so keep that in mind as I describe the set up.
With the 2x6 laying flat, at one end of the 2x6- mount the floor flange near the long edge. Leave about 1" between the edge of the flange and the edge of the board. At the other end, mount the crank. To get best alignment, mount the crank closer to the long edge opposite the flange. This puts the crank about 2-3" above the flange (your anchor point is about 2-3" higher than your hand at full draw. It makes timing the cams easier).
Center and screw the 2x4 to the back side of the 2x6- between the flange bolts and the crank bolts. I put the 2x4 along the edge of the 2x6 that is closest to the flange edge. Screw in the 6" nipple to the floor flange and cover with either the plastic tubing or thin foam and duct tape. This protects you grip and bow riser.
On the end of the rope from the crank, attach the turnbuckle making sure it is extended out. Then attach the carabiner to the turnbuckle. I also have a small loop of string loop as a safety loop. When the bow is in the board, I hook the carabiner to the bow loop, but I put the safety loop around it as well. I also never put a bow on the drawboard without an arrow in the bow. If something breaks, and the bow fires, it's not a dry fire.
I put the board in the Skill table vice and secure it.
Now, after all that, I am seriously considering getting the drawboard attachment for my LCA E-Z press. It's a little pricey, but it is a lot more compact and I am running out of space to keep the timing board set up.
Here is a picture of mine, I also agree with using the worm gear drive. Its slow, but you can also take the handle off and double nut the drive shaft and use a cordless drill. I removed the cable and replaced it with a rope. I also have a turn buckle for fine adjusts even though the worm gear is pretty precise. Also add a metal yard stick for draw lengths and I can also add my bow scale for weight. I added folding legs from an old table on one side and lay the other on my work bench. When ever I am done I can fold the leg up and stow under my work bench.
If building a horizontal board like mine you can also add an eyebolt or hook to your board once you get it built. Position the eyebolt or hookbolt so your rope will go thru it to pull straight with your string loop.