For the metalworker we start off with a great plan for a metal spiral staircase. The plan incorporates welding and metal scroll work. For access to a second level, when space is limited, this is a beautiful solution. Many years ago I built a similar laminated wood version, in a doll house I built for my daughter, one Christmas. I would love to build a telescope observatory on my garage roof, this plan would make for the perfect access. Unfortunately my moniker applies, "if time is money, then I need a loan".
For something different you can make and learn to use a angle post for your metal lathe, make some handy shop tools, a plan for a split ring lathe dog, a tapping "gidget" for threading, a plan for a small work, faceplate lathe, from odds and ends. If your flex shaft is underpowered try this versatile plan that uses a circular saw as a power source. We finish of with a nice article labeled "12 Great Metal Lathe Tricks"
There is a plan for a wood planer, which is a very interesting and involved build. It uses two motors for head power and feed power. The feed motor has a long speed reduction train which is interesting but inefficient. Modern planers pull feed power from the outboard end of the planer head and through a straight or two speed reduction gear box, eliminating the second motor. For the DIY'er this can be done with pulleys and belts as well, with less efficiency and the possibility of belt slippage, for heavy feeds. More expensive, but chains and sprockets on the last reduction steps would eliminate slippage.
Click Popular Mechanics Shop Notes Highlights 1970 to download. 3 - MB - pdf