Geared Heart - Hand crank 'upgrades'

myminifactory

I'm a big fan of the original geared heart, as is my daughter. She would love the hand cranked version, but at six years old, she needs something sturdier and more reliable to operate. The Beth's Hand Cranked Edition was fine for me, but I needed it to withstand rough handling and accommodate 6-year-old dexterity without skipping gear teeth. The spacer on the big gear helped that version run smoothly. All the tolerances in this design are very tight (.1 to .25mm), so you might need to sand them down a bit depending on your printer's capabilities. I made the axle stronger and incorporated the little gear into it, rounding it off for a better fit. The wheel is slightly different to accommodate the knob, which push-fits into the wheel and spins freely. The lock ring I designed fits with the base from the Beth version after some sanding, but I also created a new base with a groove in it. This will be a tight fit, but once it's in place, you can turn the lock ring to align the gaps and put the heart in place. The lock ring keeps the top from popping up if the gears give a little resistance. I included a copy of the big gear and a 3.75mm disc with this design, just like the Beth version. This keeps the same concept but prints cleaner, making the gears mesh better. You can see it in action on my Instagram page at https://www.instagram.com/p/BuXiaIwH_OG/. That video was before I added the lock ring, so you can see how it works without it, but I think the lock ring provides an extra layer of security.