Engine fidget toy.

Something for those who like engines and gears.

I don't know much about engines, but I like the mechanics of their movement.

So I modeled such a toy.

The assembly is simple, insert the central gear, external gears, pistons, connect them with rods and install the body cover. Who wants to rotate the engine from the back, connect Knob A and Knob B.

For smooth movement of the parts, it is important to run through the holes in the gears with a drill, and, clean the seams on the axes with a scalpel, you will remove friction

Update!!

Modified shape of pistons and engine block body, cut piston radius to prevent it from rotating and falling out

Update