Barrel Closing Tool for Watch Movements

This is a 2-piece barrel closing tool consisting of a lid and a base.  Although fairly easily machined on a lathe, I figured 3D-printing a barrel closer might be useful for some watchmakers/watch repairers.  The design of this tool is similar to Bergeon item #7922 “Tool for Closing Barrels” or Horotec MSA03.310 “Tool for Closing Watch Mainspring Barrel”.

The barrel lid should be flipped around to avoid printing overhangs (top side should be down facing the print bed).  The dimensions are such that the lid should slide freely, without resistance, onto the base.  There should also be very little side-to-side motion when in place.  If the lid resists sliding onto the base, then either the lid should be scaled up slightly, or the base should be scaled down slightly.  

This print was tested on the Prusa i3 MK3S+ and Mini+ on a 0.40mm nozzle at 0.10mm, 0.15mm, and 0.20mm layer heights.  

The example shown in photos was printed on Overture Matte Light Gray PLA.  My example with both the base and the lid shows some stringing.  You may want to print them individually to avoid stringing and/or make sure your filament is dried properly.  For added visibility, you may want to print the barrel closing lid out of a more transparent material.  

To use, the barrel drum with arbor and mainspring installed is placed on top of the barrel closing tool base (concave surface).  

Centering is important as the bottom of the arbor pokes through the bottom of the barrel and must have clearance.  The barrel lid is placed on top of the barrel drum, with the top of the arbor poking through.  

The barrel closing tool lid is then placed over the base.  Again, the top of the arbor must be centered so that there is clearance.  

Pressing down on the lid will snap the barrel lid onto the drum, thereby assembling the component.