It would be nice to have a dedicated machine for cutting gears by hobbing, but for cirkut work it really isn't needed. I looked at the same HomeShop Machinist set of plans mentioned above and did some dreaming too but the bottom line is that it would have taken more work to make the machine than I could ever get out of cutting gears not to mention the cost of the hobs. You need two, a 32 pitch and a 48 pitch with 14.5 degree pressure angles for the old cirkuts and probably more for the guys that have some special project with the modern 20 degree pressure angle stuff or metric gears.
I use a South Bend lathe and a mill with a dividing head to make the gears, and cut them with the correct gear cutters that fit a small range of teeth. After that, the gears are lapped using very fine valve grinding compound and running them with another gear that has a prime number of teeth so they mesh with every tooth (unless it has the same number as what you are making so you need to be sure they are different). Then finishing with a polishing compound usually tripoli (something like Brasso will work) I check the fit of the gears with a good set of original gears, comparing the depth of the mesh and making sure it has a good eyeball look to the teeth.
Making the gear is only half the battle, you need to make the shaft or spline depending on the drive. Getting the pinion gear to mate dead even with the ring gear and not wobble takes some precision. I use collets in the lathe and then check everything with a dial indicator. The shafts can be sweat soldered with soft solder, that's more than enough strength and allows removal and adjustment if not perfect. The original gears are swedged in place and the shaft is spun down to give a nice little rounded bump in the center. To remove an original shaft, I have a special holder and use a punch and hammer. They come right out, no soldered joints.
Ron in Alaska