When making automata there is sometimes need for careful thinking. For me, gluing together a large camshaft always requires focus, and I often wait until I'm mentally set before starting. The combination of getting things in the right place, in the right orientation, and at right angles to the shaft while working with CA adhesive is sometimes adventurous. Even though I thought I had preplanned carefully when doing this camshaft, I found on assembly that I had reversed the position of two cams on each side and that the head movements expected were not as planned. Here's a photo.
The second and third cams from the left are reversed as well as the sixth and seventh. This is where a good $#@&* is usually warranted. Here is the new one.
So how did I do it? One choice is to chuck it in the garbage and start anew. Another is to try and recover the gears, since they require more work to make, and scrap the cams.
Lastly you can try to save all the pieces, sacrificing only the shaft. I chose the last one. Here's how it goes.
Cut the shaft, in this case 3/8" diameter, out from between the cams/gears leaving a little protruding out on each side (1/16"). Drill thru the dowel using a drill 1/16" smaller diameter that the shaft size. (Make sure when drilling you have the cam flat. I placed it over a 1/2" hole that received the short stub on the other side.) Here's what a cam should like after doing this.
Now using a utility knife, moving around the circle, carefully push the tip down into the remaining dowel splitting it slightly several times. Repeat on the other side
Next using a flat object, like the blade of a small slotted screwdriver, push the dowel remains inward until they break. Do both sides. You really only need to get one side completely clear so you can re-drill the original original hole. I do both sides and remove as much dowel material as I can just to ensure better drilling accuracy. Sand the backside of the cam/gear flat so it lies flat for drilling. Using a forsner bit carefully drill out any remaining dowel bits and glue. Now you can assemble the cams/gears on a new shaft.
Automata is a creative blend of my life interests , engineering, art and woodworking.