My childhood Mamod SE.2a steam engine survives, but the accessories are lost to the mists of time. So my grandson suggested we print some! (smart kid) Here is our first effort*: a working table saw that will cut 1/16" thick balsa wood sheets. 

The table and base is printed in PLA. The blade is a 1-1/4" (32mm) diameter hobby tool wood blade 1/64" thick (from Princess Auto 8121337). Additional hardware for the saw itself includes:
1 of M2 heat-set thread insert
1 of M2 x 6mm machine screw
1 of M4 x 10mm machine screw

The thread insert is set in the "axle" component through the "Pulley", mounting the blade between them. The 3 must be assembled in place within the table -- tweezers may be required. The washer is mounted outside to the other end of the axle -- no insert required, just thread the M4 into the plastic. We found separate bearings were not required -- a drop of light machine oil makes a sufficient viscous bearing, plastic on plastic. Just don't get any on the pulley itself! 

If you use the base mounting requires:
8 of M3 heat-set thread inserts
4 of M3 x 10mm machine screws
4 of M3 x 20mm machine screws

(Or you could just screw things down to a piece of plywood like I did as a child long before 3D printers)

The drive belt is printed in TPU 95. It took a lot of fiddling to get the profile just right -- strong enough to hold up without stretching, flexible enough to run around the pulleys without robbing too much power from the system. 

I'll include the Freecad design files for remixing. 

Note: The storage case in the photos is a remix of another's work. I can post that separately. The fuel and water bottles are my own design, and I'll post them separately too. But be forewarned: PLA and many other filaments are not suitable to print a container for alcohol fuels. PCTG was required. 

Carrying case: 

Bottles:

*well, Version 4 of our first effort -- the design was refined as we experimented with different ideas.