This is a remix of LarkysPrints Watch Escapement Desk Toy.
It replaces the 3D Printed main spring with a steel recoil spring from a chainsaw. These parts are readily available as spares on Amazon or Ebay typically for less than $10 USD. The specific part used in this build is a Husqvarna 545008013 Starter Spring but others could easily be adapted.
Let me start by saying if you're having trouble getting the movement to function using Karl's original design this will not help you or solve your running issues. You should debug/tune the original design before attempting this modification.
Run time is approximately 20 minutes.
You will need the following additional hardware
M3 x 12: 10
M3 x 16: 1
Recoil Starter Spring: 1
- Fashion a loop at the large end of the recoil spring using pliers that will tightly fit the large central pin on the Mainspring Support front. Remove from the support pin, will be attached last.
Place the smaller/inner eye end of the recoil spring into the winding stem and secure with the M3 x 16 screw.
Mount the Mainspring Cage front to the Main Spring Support using 2 x M3 12 screws
Begin at the top of the cage and start attaching the Cage Back to the Cage front section using M3 x 12 screws, working your way down from top to bottom ensuring none of the mainspring is outside of the cage as you go.
- Attach loop from the recoil spring to the Main spring support pin.
I would suggest printing with 3 x walls and 3 x top/bottom layers
Mainspring Front Support - Printed at 30% infill, 3 x walls, 3 top and bottom layers. The only difference from the original is the placement of the two screw holes to support the cage.
Winding Stem - Printed 100% infill - When printing the Winding Stem support must be used. Also note that the lower hole on the winding stem that receives the M3 16 tends to get clogged/filled with support material and possibly will need to be drilled out prior to assembly. I used 3/32 drill bit.
Modified Fork - Printed 30% infill. This has an additional collar that provides less side to side play at the striker end.
Update 3/24/19 - Printing holes can always be an issue depending on how well your 3D Printer is calibrated. With this in mind I have reduced the diameter of all the holes (V3) to be 2.4mm. Better the holes are too small than too big, you can always drill them out to suit.
Lots of winding going on here, run time is about 20 mins.
This was designed using Tinkercad.