They already are turning in to little wack job libertarians, so that seed has been planted.
Forge throwing axes
Cool idea, need to learn more about this. I'll look in to it.
Try to find some cheap cars that don't run and get them running to sell for a profit. Put the money towards their first car.
I like this other than lack of space. I have limited room in my shop as it is. Need to clean up before I dive in to this, which they'll be helping with.
Pick up a couple non running dirt bikes / dual sports.
Take apart and rebuild with kids.
Move them on, onto quads etc.
I like this other than it's not super easy to play with them. The airport used to be covered with kids ripping around on motorized toys, now the management has turned in to nazis about it. God forbid we encourage kids to be around the airport.
If they have any artistic ability: art or small sculptures from sheet metal/steel scrap. I made little stick figure dudes from coat hangers and other stuff. They can give them to friends/family or sell locally.
Easy to get rid of if they want to try something else. But with a little help and guidance from Dad if they like it they can go as far as they want.
Same thought: steel furniture. Well, shop tables to start. Could do a basic workbench as a first project, then that's their area to have a messy project and do kid things. If they have a knack, some sheetmetal folding to make a top, sides, or drawers, etc.
My final idea: any core car engines sitting around? Like a worn out ChebbyTreeFitty? Let them tear it down, figure out how it kinda works, find anything wrong, and put it back together. If they have a knack for it, then rebuild/flip common engines for their future car funds.
Neither one is all that artsy......until they are. I do have a couple of airplane engines that need assembly, but I'm not quite ready for them. They would take up a lot less space put together though, which solves some other problems. One of the goals of this is they get feedback fairly quickly after the labor. A small engine rebuild would probably do that.
Trebuchet
Flamethrower
Spud gun
Pitching machine or batting cage
RC car/plane built from kit or robotics of any kind
Junior's eyes just lit up when I said trebuchet...
Kit plane
They've grown up around airplanes so they're a bit jaded. They haven't really figured out how cool they are. I was the same way and didn't figure it out until high school. We are closing in on flying one that has been going together for a few years. Hopefully we do that in the next month.
Smurf mentioned it, but forging and layering sime steel could be rad.
Or building a diy racing sim rig could be cool if they like racing games
The steel idea is cool, trying to keep them off of games though.
Got a river around? Get river rock, use it for the body on birds, frogs, ants, etc, use 1/4" rod to make the rest of the parts, have a bunch dry fit, then use a tube of epoxy to get it all affixed. Sell at a farmer market/craft fair/etc.
No artists in my family like that.
I'll second the vote for trebuchet.
I have always wanted to build one
Pretty sure this is high on the list.
Something useful at home? Cutting board or desk organizer.
Treadmill lathe/wind generator
Ever thought to ask them what they're into? Might be able to fabricobble something like that. Soccer ball net, basketball return thing.
I have an old treadmill motor just for this reason, maybe we'll do something with that. They do have interest in electronics.
My daughter has an interest in woodworking. She has mentioned a cutting board.
I ask them all the time. Lots of typical tween/teen answers "I don't know"
Massive remodel project on your house. Put them to work doing demo, loading the truck, scraping subfloor, sanding, pulling nails etc.
Landscaping is another good one.
At least that was how my summers went
They actually are pretty active in most of those projects, which is why I was to reward them with building something THEY want to build, while hopefully learning something along the way.
My brain immediately said Go-karts.
If you want to get them addicted for life, pick up two racing karts and find a local track.
Where are you located?
Tracks aren't too far away. May study this more.
Cannon. Everyone needs some kind of cannon.
I'll try to learn about this idea too.