Today we are going to cover the process of changing the mainspring in an Illinois Bunn Special Railroad Grade Pocket Watch.
Please remember, in this case, the watch was fully serviced six months ago, but the mainspring was fine, and I did not change it at the time. Since then, it has broken, and I’ve done this procedure to only change the mainspring.
Here are the steps we need to follow to change the mainspring
- Decase the watch (remove the watch movement from the case)
- Remove the hands from the watch
- With the watch face down, remove the Ratchet Wheel
- Remove the Main Wheel
- Remove the main bridge by unscrewing the three screws on the main bridge
- Remove the mainspring barrel
- Open the mainspring barrel and remove the broken spring and theBarrel Arbor
- Clean the Arbor and the Barrel
- Get the new spring for the watch
- Clean and Pre-Oil the spring
- Using a mainspring winder, wind the spring into the winder
- Place the winder into the barrel, making sure that the T-bar ends are inserted into the barrel hole
- Release the spring into the barrel
- Place the Arbor, in its correct position, into the barrel in the inner part of the spring
- Place a bit more spring oil onto the spring
- Place the barrel cap onto the barrel, and tighten it down
- Place the Barrel into the movement
- Place the Main Bridge back onto the watch, and slowly tighten the three screws (not all the way)
- Make sure that the bridge is fitted onto the movement and that the 1st wheel and barrel arbor are seated correctly
- Tighten the three screws
- Check all other screws on the movement
- Place the Main Wheel back onto the Main Bridge, and use the “reverse thread” screw to tighten it in place
- Place the Ratchet Wheel back onto the Bridge and tighten it down
- Give the Ratchet Wheel a couple of turns, the balance should start turning on its own
- Re-Case the watch into the Frame of the pocket watch case.
- Put the Back Cover onto the Case Frame
- Set the Hands back into position
- Place the Bezel and Crystal back onto the Front of the watch case frame
- Wide the watch, test and time.
Thanks for following along with these instructions, and I hope that this helps. If you have any questions, please let me know.