squale..
the plastic parts, from experience, would go very well on a smallish cnc lathe. with some decent programming they look like their cycle times would be around 2 minutes each, plus the manual center drilling.. the slits could be cut accurately and efficiently with a simple jig and a band saw with an appropriately thick blade, likewise even a router table, or an improvised router table with a small laminate trimmer and jig would be ok. a jig for this could be made pretty easily, especially if you didnt mind hiring someone. i could imagine making a jig for this for a bandsaw for you for under $200(aluminum plate, delrin bushings for the table slots, indexing rotary mount for part., not that 'just any' shop would do it for that price. that is just an example, not a proposition so much, rfq site might actually deliver a very low quote on these parts in general, given the type of competition there.
a $750 imported lathe seems to me to need about $1000+/- $500 of parts put into it to make it into something like the c6. you need 2 stepper drivers, 2 stepper motors, 2 motor mounting plates, 4 pulleys, 2 mxl belts, a parallel port card (get a $150ish one that has the lathe indexer inputs, etc.. unless you are good with electronics and can figure all that out), a method of indexing the lathe chuck, and some tooling.. all ofthis can be had for around $2000
then to do the slots, a manual mill and bandsaw can both be purchased new or used for aroud $2000 more or less for something worth owning. $1000 will get you new tools from harborfreight.com. a mill drill, lathe, and bandsaw from them will be under $2000 upto about $4500 for better stuff. to cnc it all is like another $2000/machine. allot less could still do a good job on these plastic parts.
at that point you would have a small but flexible shop setup that fits in a corner and can make very accurate parts with automation to do the hardest surfaces. you may find the learning curve steep though. i know i took a few years of casual interest before being able to really make good parts.. but, i always had to rely on my own pathetic income to purchase tools and stuff. it took 5 years in my case of constant bargain hunting, etc. to get a decent shop together... and i still couldnt make the parts you have specified except as prototypes.. once i cnc my small lathe, that would be another story.
oh, and as for doing a rubber mold of these parts.. it will be hard to make concentric round parts using molding. also, without looking at the parts again, it seems to me you will pretty much still have to chuck them to center drill. If these parts are more like adapters and dont spin or have strict concentricity requirements, molding might be a very good and inexpensive option. then you just need a small manual lathe to center drill. or, you could try and put a plug in the mold, but that is not an operation i would want to do without facilities.
i just wouldnt recommend this exact method
Design & Development
My Portfolio: www.robertguyser.com | CAD Blog I Contribute to: http://www.jeffcad.info