Full Plate Pocket Watch assembly technique

Watchoutnow · March 23, 2023

I reprised my efforts to service an Elgin 18s Grade 207 full plate PW and successfully assembled it. I used the following method to align the train.

As advised in one of Peter Grande's videos I placed the top plate upside down on to a casing pad and placed all the wheels and pallet fork with their top pivots down onto the plate. The following steps he leaves out and I had to devise.

The issue with a full plate assembly is that the pallet fork is under the same bridge as the train, which makes it difficult to test the train before placing the pallet fork, but you need to do this. So, this is how I proceeded.

After placing all components upside-down onto the top plate, I positioned the mainplate on top using the center wheel post and the sub seconds pivot as alignment aids. I also used the four plate post as alignment aids. I gently positioned the mainplate in place and pinched the mainplate and bottom of the casing pad that the top plate is resting on between my gloved fingers and picked it up. I then aligned the train starting from the third wheel side working toward the escape wheel but ignoring the pallet fork. Once I had the train aligned and spinning free, still pinched between my fingers, I gently positioned the casing pad to expose the bridge screw hole on the top plate on the third wheel side and very very lightly screwed in this screw just so it "kissed" the top plate to prevent this side of the plate from jumping. I then turned my attention to the pallet fork side. There is still a gap on this side and plenty of room to wiggle the pallet fork in place. Once the pallet fork is in place you should see the plate post sitting flush to the top plate. Very very lightly attach the second bridge screw to the top plate on the pallet fork side, give the pallet fork a little wiggle to make sure its teeth are engaging the escape wheel then give all the pivots a good inspection under a magnification and when satisfied, tighten the two screws.

I hope this helps anyone who is struggling with aligning a full plate. Essentially, start at the third wheel (hopefully the center wheel didn't jump) and work your way to the escape wheel. When the train is spinning free, lightly attach the bridge screw on the third wheel side to hold all lightly in place and then work on the pallet fork. It's easier than hoping all will align in one shot, which it won't!

JohnR725 · March 23, 2023

Yes 18 size American full plate watches can be a pain. Then there's another way to do this which is use a handy little tool made out of a piece of mainspring to hold the pallet fork to the top plate. Then with the pallet fork safely in where it's supposed to be the rest of the plates assembled you can bring the plate down with the pallet fork and get it all together.

So basically just a piece of old mainspring folded in half and heat up the fold so it softens and then it forms this nice shape of a little spring for holding things in place. Pierre really fancy can cut a slit at the end to go over the arbor the pallet fork otherwise you can just slip but over the pallet fork itself..