Blacksmith Automaton - a free 3D model from Shapekit

A wooden-toy style automaton you print. Turn the crank on the front of the box and the smith slowly raises his hammer over his head. At the top the follower rod drops off the step of a snail cam, and the hammer falls onto the horseshoe under its own weight, with a real clack. While the hammer is up, a second cam lifts his other arm, so he raises the hot horseshoe off the anvil with his tongs, looks at it and puts it back for the next blow. Both arms simply rest on the tops of the rods, so nothing is glued to the mechanism, and you can see the cams and rods work through the windows of the box. Every part prints without supports.

Parts (each STL is already placed the right way up for printing)
- blacksmith-automaton-case.stl: The four walls in one piece, with a window in each side, a bearing for the camshaft in the front and the back wall, and a column in each corner for the screws of the base and the deck. Print: Standing up, as in the file. No supports: the windows have 45° tops.
- blacksmith-automaton-base.stl: The bottom of the box, with four feet. Four M3 × 16 screws go up through the feet into the box. Print: Upside down, feet up.
- blacksmith-automaton-deck.stl: The top of the box. The two guide tubes underneath keep the rods straight; the smith and the stump are screwed on from below. Print: Upside down, tubes up.
- blacksmith-automaton-camshaft.stl: A D-shaped shaft with a flange at the back. It runs in the two bearings of the box and carries both cams and the crank, so they can only go on one way round. Print: Lying on its flat side.
- blacksmith-automaton-hammer-cam.stl: A snail cam: over most of the turn it lifts the hammer rod 13 mm, then the rod drops off its step. Its hub points to the middle of the shaft. Print: Cam face down, hub up.
- blacksmith-automaton-tongs-cam.stl: A round cam with one gentle bump that lifts the tongs while the hammer is up. Print: Cam face down, hub up.
- blacksmith-automaton-spacer.stl (print 2): Fills the shaft between a cam and the wall, so each cam stays right under its rod. Print: Standing on one end.
- blacksmith-automaton-crank.stl: Sits on the front end of the camshaft, held by an M3 × 10 and a washer. Print: Flat.
- blacksmith-automaton-knob.stl: Turns on an M3 × 20 that screws into the end of the crank. Print: Standing on its flat end.
- blacksmith-automaton-rod.stl (print 2): A Ø6 mm rod with a flat foot that rides on its cam and a round top that the arm rests on. Both rods are the same. Print: Standing on its foot.
- blacksmith-automaton-smith.stl: The figure, in a long coat and a leather apron, with a beard and a cap. The arms turn on M3 × 16 screws in his shoulders; two M3 × 10 hold him to the deck from below. Print: Standing on his feet. No supports.
- blacksmith-automaton-hammer-arm.stl: His right arm with the sledgehammer. It rests on the hammer rod. Print: Lying flat, on its outer side.
- blacksmith-automaton-tongs-arm.stl: His left arm with the tongs. The jaw reaches in over the horseshoe on the anvil. Print: Lying flat, on its outer side, jaw up.
- blacksmith-automaton-horseshoe.stl: Glued under the jaw of the tongs, so it lies on the anvil and comes up with the tongs. Print: Flat.
- blacksmith-automaton-anvil.stl: A London-pattern anvil with a horn and a hardy hole. It sits on the peg of the stump. Print: Standing on its foot. No supports.
- blacksmith-automaton-stump.stl: The block of wood the anvil stands on, with year rings on top. One M3 × 10 holds it to the deck. Print: Standing up, peg on top.

Also needed (not printed)
- M3 screws: 6 × M3 × 16 (4 for the base, 2 for the shoulders), 8 × M3 × 10 (4 for the deck, 3 under the smith and the stump, 1 for the crank) and 1 × M3 × 20 for the knob, plus one M3 washer. They cut their own thread in the plastic.
- A drop of superglue for the horseshoe, and a little candle wax or dry PTFE spray on the cams and rods.

Print settings: 0.4 mm nozzle, 0.20 mm layer height, 3 walls, 15% infill, PLA material.

Assembly
1. Print the parts: Print everything the way it lies in the files: no part needs supports. Clean the elephant's foot off the cams, the rod feet and the D-holes so they slide on.
2. Box: Set the box on the base and screw it on from below with four M3 × 16 through the feet.
3. Camshaft and cams: Push the camshaft in from the back. Inside the box, thread it through a spacer, the tongs cam (cam towards the back, hub to the front), the hammer cam (hub to the back, cam towards the front) and the second spacer, then out through the front bearing. The D-shape only lets the cams on one way round.
4. Crank: Push the crank onto the front end of the camshaft and fix it with an M3 × 10 and a washer. Screw the knob on with the M3 × 20, just tight enough that it still turns.
5. Deck: Screw the smith (2 × M3 × 10) and the stump (1 × M3 × 10) onto the deck from below, and push the anvil onto the stump's peg. Stand the two rods on their cams, lower the deck over them so each rod slides into its tube, and screw the deck on with four M3 × 10.
6. Arms: Glue the horseshoe under the jaw of the tongs. Screw both arms to the shoulders with an M3 × 16, the screw head on the outside, and back each screw off a little so the arm drops freely onto its rod.
7. Turn it: Turn the crank clockwise, seen from the front. The hammer rises slowly and drops once every turn; between blows the tongs lift the horseshoe. If an arm sticks, a little wax on the rod top and the cam helps.

Safety: Small parts and screws: keep them away from young children.

License: Creative Commons Attribution-NonCommercial 4.0 (CC BY-NC 4.0)
https://creativecommons.org/licenses/by-nc/4.0/
Print it, remix it and share it, as long as you credit Shapekit and don't sell the files or the prints.
