"Pete C." wrote in message
...

Given the printing speed of affordable 3D printers I don't even
consider
them reasonable for test parts vs. conventional CNC machining of
machinable wax test parts. Why would I want to wait all day for a
test
part that looks like some kid made it with a can of cheese-wiz when
I
can machine a wax part in 30 min?

Look around at the sculpted items you might customize, like doorknobs,
faucet handles, gearshift knobs, lamp arms. They have a stress
concentration where they attach to a shaft, where plastic won't last
long. My homemade outdoor faucet handle has a brass handgrip on an
aluminum shank, which was easier to broach to match the double-flatted
faucet shaft.

Replacements for failed commercial parts might be a good application,
but you'd have to understand why the original part failed. For example
I made a new aluminum augur clutch handle mount for my snow blower
after the plastic one cracked from embrittlement in very cold weather.

This chair is another good example of customization where home 3D
printing isn't appropriate. I wanted a comfortable high-backed
computer desk chair I could recline in to watch TV, but armless so I
could slide it in under the keyboard drawer.

I finally bought a high-backed armchair on sale and replaced the arm
assemblies that join the seat and back with aluminum diamond plate
triangles. I relocated the holes for the back bolts to raise it just
enough to serve as a headrest. The upper leg of the triangles is under
a lot of tension when I recline and a brittle cast material there
could dump me on the floor without warning if it cracked. The diamond
plate is ductile and homogeneous.

jsw