I turn my styrofoam nose cones using a drill press, although I have seen some people turn them using hand(electric) drills. A good trick is to use a hardwood dowel as your core, and make it long enough to protrude through both the base and tip of the nose cone. Chuck the end at the base, and then turn the tip end to a slight point, enough that you can wedge it into the core of an old set of sealed bearings. I found a single childs-size rollerblade boot on the side of the road a while back and pulled the eight sealed bearings from it. One of the big advantages to using paper mache to cover the styrofoam is that it sands very easily and is surprisingly strong. After you have built up several layers of paper, do a coat or two of thinned fill-n-finish to fill any gaps and make everything nicely smooth. If you want a *really* strong and slick nose cone, dilute some epoxy with acetone to paintable consistency and paint.
It is a fair bit of work, of course, but if you are already making your own motors, you are well aware of the amount of work that goes into full-ex launches.
BTW, I think you will find that a small bench-top drill press in the $80 - $100 price range well worth the investment if you plan to get seriously into rocketry. I used my drill press, along with an angle grinder and set of files to turn all of the tooling I use to make my rammed bentonite nozzles.
If you have more time than cash, you could easily kick it old-skool and make yourself a non-electric, pedal-driven lathe just like the ones used for thousands of years prior to the development of electric motors.
Yet another option is to find an old upright vacuum cleaner and use it to power your lathe. You won't get enough torque to turn much more than styrofoam and paper, but if you disassemble it carefully, you can keep the suction active such that you can use it to both drive the lathe *and* suck up all the styrofoam dust at the same time.
I have had such good results with my styrofoam/paper mache construction techniques that I plan to work on a series of cigar-shaped rockets in the same style. I actually have two upright vacuum cleaners (yet again, pulled from the side of the road) one of which is in the process of being re-purposed as a light-duty lathe with a 6 foot bed.
Also, in regards to delay grains and ejection charges for EX motors, I did not experience any of the difficulties many people report. My first four motors used plugged forward bulkheads while I was testing retention techniques. Motors 3 and 4 failed while trying to determine minimal retention requirements. For the fifth test, I returned to the stronger retention that worked on the first two tests and added a delay and ejection charge. It worked flawlessly. Here is a link to some pics and video:
https://sites.google.com/site/gnomadexperimentalrocketry/Home/static-motor-tests/st-005
Here are some photographs of my delay grains. The grey material is the standard bentonite/wax mix. The white/red material is the delay mix developed by Chuck Knight and documented on Richard Nakka's site.
https://picasaweb.google.com/gnomad/DelayGrains
No formulas given on that page, so that link should be TRF-safe. I have used exactly the same technique on some 500 motors now ranging from low E through high G total impulse with only a few failures. Analysis of every failure revealed a cause in construction, not design. With more attention to detail in construction, no failure types were repeated.
Finally, if you are interested in sugar propellants, you *definitely* need to get on the SugPro mailing list. The list is generally quiet until someone asks a question, but questions rarely go unanswered.
Roughly what size rocket will you be building?
