Scribing

Check out Swanny's Scribing tips. He uses a scribing tool he bought for six bucks. You should also check out Harbor Freight or Princess Auto (or some other "discount" tool store) for a set of cheapo dental tools. I picked up a pack of them for less than ten dollars. Now my kid's teeth are in great shape!

Nah, just kidding, I do find them handy for rescribing panels lines etc.

Hobby Lobby has cheap scribing tools, around $4 or so.

You could also try looking for second-hand tools from unlikely sources...

I've heard lots of people have success with dental tools, but I haven't tried that route.

And then in my last job, we used a few tiny (~1/32") end mills, but being so small that they broke pretty easily.  I've taken a couple of the broken ones home and tried using them with varying success... they're very sensitive to direction/angle of use.  So if you can find a machinist, you may want to ask if he's got any small broken end mills (it may help if he works at or has done work for a scientific company or a university... I think they're more likely to come up with odd-ball stuff that needs cutters that small).

In addition to a purpose-built scribing tool, I also use a sewing needle chucked in a pin vise.

My dentist has unloaded a bunch of dental tools on me. Some he was just going to pitch anyway. Don't be afraid to ask. Some of them work just as good as the expensive ones.

i started out with a sowing need,cut in half and the inserted into an exacto knife handle,it served it's purpose until i found the Testors scriber that i wanted

The back side of my wornout #11 blades.

What can I say... I'm cheap. 

Ok ok, I also have one of those pick sets I bought for my automotive toolbox.
It was cheap - one handle, four different shaped picks, in a plastic pouch.