Illinois Bunn Special, Mainspring Replacement

Hey Guys;

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.

 

Video Tutorial….

 

Written Instructions…

Here are the steps we need to follow to change the mainspring

  1. Decase the watch (remove the watch movement from the case)
  2. Remove the hands from the watch
  3. With the watch face down, remove the Ratchet Wheel
  4. Remove the Main Wheel
  5. Remove the main bridge by unscrewing the three screws on the main bridge
  6. Remove the mainspring barrel
  7. Open the mainspring barrel and remove the broken spring and theBarrel Arbor
  8. Clean the Arbor and the Barrel
  9. Get the new spring for the watch
  10. Clean and Pre-Oil the spring
  11. Using a mainspring winder, wind the spring into the winder
  12. Place the winder into the barrel, making sure that the T-bar ends are inserted into the barrel hole
  13. Release the spring into the barrel
  14. Place the Arbor, in its correct position, into the barrel in the inner part of the spring
  15. Place a bit more spring oil onto the spring
  16. Place the barrel cap onto the barrel, and tighten it down
  17. Place the Barrel into the movement
  18. Place the Main Bridge back onto the watch, and slowly tighten the three screws (not all the way)
  19. Make sure that the bridge is fitted onto the movement and that the 1st wheel and barrel arbor are seated correctly
  20. Tighten the three screws
  21. Check all other screws on the movement
  22. Place the Main Wheel back onto the Main Bridge, and use the “reverse thread” screw to tighten it in place
  23. Place the Ratchet Wheel back onto the Bridge and tighten it down
  24. Give the Ratchet Wheel a couple of turns, the balance should start turning on its own
  25. Re-Case the watch into the Frame of the pocket watch case.
  26. Put the Back Cover onto the Case Frame
  27. Set the Hands back into position
  28. Place the Bezel and Crystal back onto the Front of the watch case frame
  29. Wide the watch, test and time.
  30. Done!

 

Thanks for following along with these instructions, and I hope that this helps.  If you have any questions, please let me know.

 

 

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