While PVC pipe based motors are a fine way to get into experimental rocketry, it's not long before you will want to start using metal motors. That was the situation I found myself in. I didn't have a metal lathe, and that is really the starting point for all rocket motors. While you could buy off the shelf reloadable motors, they are not designed for anything other than one, specific propellant. There is little flexibility in motor design. While you may be able to change the throat size, the casing length and diameter are fixed. Not only that, but the price of most casings are very high.
I looked for larger, used lathes. Unable to locate any for a reasonable price. I opted to look at the small, import hobby sized lathes. They are commonly referred to as 7"x12" lathes. That is, 7" swing over the bed, and a bed length of 12". You can actually only get about a 4" diameter chunk of metal in it, as the tool post is too close to get anything larger in it. The 12" bed length is also too short to turn a long motor casing. While these are limitations, it will allow you to turn nozzles and closures about as big as you would ever want. The casings are not a real issue, as there is no great need to do any turning there anyway. Just buy the casing tubes in the size you want.
I found several places to buy the mini lathes. As they are all made by the same Chinese manufacturer, I went for the best price. Homier Mobile Merchants had the best price at $299, while others sell the lathe with more optional equipment for a higher price. The lathe comes with the (3") 3 jaw chuck with inside and outside jaws, dead end center, tools and the gears for thread cutting.
Above is my lathe and some tools.
A few things you will need, 5/16" high speed steel tools, center drill set, good dial calipers and/or micrometers and a drill chuck for the tail stock.
Here are the drill chucks for the tail stock, the top one I made (the taper), the bottom one I ordered.
The drill chucks are really essential, I ordered the chuck and taper from Harbor Freight when I got my lathe, but in my impatience I went ahead and made a taper for a 1/2" drill chuck I already had. Of course a good set of standard drill bits are in order. In the picture above, I have a 3/4" drill bit in the tail stock. That's about as big (if not too big) as you can use without pulling the lathe too hard.
Here's a great place to get you started on mine lathes. http://www.mini-lathe.com/
My 14" Metal Chop Saw
Above is the saw I use to cut the bar stock for nozzles/closures and the tubing for casings. You could use a hack saw, if you have unlimited energy. Or, a better option would be a small metal band saw. I think I paid $129 for this one.
My Little Bench Top Drill Press
This little drill press comes in handy for drilling out the casings, nozzles and closures for threading. It's not very powerful but gets the job done. It's a couple of years old and only cost $79. Notice the thing on the drill press bed. It's a piece of angle iron welded to a piece of rectangular tubing, with a stop welded to the end. I use it to hold the casings, nozzles or any cylindrical part I need to drill into. By clamping to the drill press bed I can make holes that are all consistent and symmetrical.