K, On 1/2" that you are not cutting alot of, stick with the oxy-acty it will be much faster unless you really step up on the plasma unit, and most likely, you will get a better edge and possibly as fast of cut speed. I know ours will torch cut 1" A-36 with less than probably 0.015" draft angle when tuned up poperly. Until you start cutting a significant part of a day, the non-cnc should be fine.
oxy acc pattern cutter
I built one years ago and have a video on youtube
Other info on web page
Mine used wooden patterns and a manual tracer works great
I used to have 3 different magnetic tracers years ago. Every time I sold one I found I couldn't live without it, and had to go buy another one to rebuild. They are hard to come by used, and even at auctions they never seem to go cheap. Plan to spend $500 or so on one. I built a magnet for one of mine. I wound my own electromagnet around a core of stressproof that I made a collet in the top of. Mount this in a couple bearings and stick it inside a nonconductive housing that you wind your magnet on. Spin the bottom of the shaft with a pulley and a gearboix and you are in business. For for a stylus I took several diameters of bar stock and turned one end of each to fit the collet, and knurled the other end. The knurled end walks around your steel pattern at various speeds. It was handy as heck.
Take a handfull of pipe drops and some washers and by changing tips, you can trace a dozen different sized circles around the inside and outside of these parts. Tack weld some flat bar to them and you can make some pretty complicated templates.
I built dozens of rippers, thumbs, etc back before I had my boring mill. I simply used my tracer to cut the parts, and a overiszed but perfect hole. I machined bushings on my lathe, stuck them on a pin, tacked everything in place and welded them out. The fit was typically really nice. Not as good as a boring mill does, but close enough for working in the dirt.
Go find a motor rewind shop and see what they charge to wind an electromagnet. It's surprisingly cheap.
TorchMate has a 2' x 2' cnc machine available for $2000.....great for a small shop.....just add your plasma cutter or router! I have a 4' x 4' PlasmaCam cnc with a Hypertherm Powermax45......it is only 2 years old and has paid for itself a couple of times over....just using it part time. Here are a few pics of the PlasmaCam and parts cut with it.