I recently had a friend with a Hamilton 992B to sell and he told me it only needed a mainspring.
I asked how he knew that was the problem. He replied "It is all wound tight and still won't run" - - so I said I would need to look at it before I could commit to buy it. So, I carefully removed the balance assembly and then removed the two screws in the pallet bridge and lifter the pallet fork out, and the watch began to run and unwind the spring. NOW - Here's the problem, The arbor was still in the pallet bridge when I lifted it off, and the pallet fork was preventing escape of the spring's energy, so in my removal of the pallet fork, I separated the pallet fork from the arbor. Is tis a friction fit? I noticed a small groove around the pallet arbor - what is that for? Should it be loose enough in the pallet fork to separate the arbor and the fork?? As always with the fabulous 185 community, Any info greatly appreciated - -

Clark, "looking" at a watch in a way that caused a unrestricted rundown of the wheel train WILL damage the whole movement. You "let down" a 60 hour movement in a few seconds. What does that mean, each full rotation (of 6) of the mainspring is about 10 hours of clock operation. 10 hours x 60 minutes = 600 rotations of the seconds wheel x 6 (winds of the mainspring) = 3600 rotations of that seconds wheel. The escape wheel rotates 15 times each minute = 54,000 rotations of the escape wheel in one complete unwind of the mainspring. I expect that took something less than 20 seconds (1/3 minute) to unwind the mainspring. This means the escape wheel has spun around 54,000 times in that 20 seconds. That means that the release of the wheel train forced the pinions of the escape wheel to exceed 162,000 RPMs. Any failure of old lube to sustain jewel/pinion separation at that speed will seriously damage the pinions of the escape wheel and probably the minute wheel as well which has been forced to exceed 11,000 RPMs.
In fairness to the seller, I suggest that you just buy the watch, carefully put the parts in a safe container and send it to someone who can clean, inspect, fix, lube and time this movement. Then you will have a nice watch.

David - Thank you for the info. I concede that I have done the wrong thing here, however I did not allow the unimpeded unwinding - as it was NOT fully wound up as I thought, so I held the click on the winding wheel and released the tension by holding the crown until it was "relaxed but I did let it run down for maybe 2or3 seconds after the tension was relaxed. My interest is if the pallet arbor is pressed into the fork or how it is retained. Thanks for enlightening me further.

Hi Clark,

It should be a friction fit. It is possible the arbor can be tapped back in place. If not the arbors are available or you can pick up another pallet complete. The 992B parts are pretty easy to find if needed.

Rob
www.pocketwatchrepairs.net

Rob-Thanks you for this valued info. I hoped the arbor would be able to be tapped back in place. It is there and I was able to easily lift it out of the lower pallet jewel with tweezers. Thankfully it is there and looks OK. When I removed the pallet bridge, and then lifted out the pallet fork, that arbor remained in the lower jewel, and I was able to retrieve it. So I am off to the expert to get it re-assembled and checked out. Thanks again for the answer I needed.