Setting up the Chime and Strike trains on a Hermle 340-020
by David LaBounty
•Assemble the movement but leave off the chime idler wheel, chime lock plate, chime stop cam, hour pipe/snail, minute wheel,and gathering pallet.
Chime Train Setup...
•The chime 5th wheel is the warning wheel and has the warning pin. This wheel rotates CW during operation. Rotate the warning wheel until the warning pin is in line with the fly. This will provide 90 degs. of rotation of the warning wheel as it goes into warning.
•Hold a finger in the warning wheel so it doesn't rotate out of position and install the stop cam onto the extended arbor just below the warning wheel. The stop cam should be positioned so the chime train comes to a stop with the warning pin in close proximity to the fly pinion. Be sure the stop cam is tight on the arbor.
•With the chime train in the "stop" position, install the chime lock plate so it has just finished the 1/4 or 3/4 chime sequence. This cam goes onto the extension of the 3rd wheel. It rotates CW during operation and the pin on the lever should be positioned in the notch so it is in the middle of the short flat area on the cam. It is best to err with the pin slightly advanced, on the left side of the notch, rather than on the right side. Tighten the cam on the arbor.
•Check to be sure the position of the warning pin on the chime 5th wheel is still where it needs to be at stop.
•Loosely slip the chime idler wheel onto the rear of the 3rd wheel arbor (back of the movement) and engage it with the rest of the gearing on the back plate. The wheel goes towards the plate and the screw towards the outside.
•With the chime train in the "stop" position and a finger on the warning wheel, rotate the idler wheel in a CCW direction. This will rotate the chime pin barrel and lift the hammers. The hammers should be free to drop and not be partially lifted by the strike train. Watch for a sequential drop of the hammers starting with the hammer closest to the front plate and ending with the next to last hammer. (The first four hammers are for the WMC and the last hammer is only used during the strike.)
•Once the proper sequence has been identified, tighten the idler wheel at the point the last hammer just drops.
•Test the chime train through several sequences and watch for a hammer being lifted during warning or hanging up at the end of the chime sequence. If either happens, twist the idler on the arbor one way or the other until the problem is resolved.
•The chime train has a self synching device which arrests the train after the 3/4 and doesn't release it until the hour. This is the extra lever just behind the stop lever which drops into a notch on the inside of the chime lock plate. Problems can arise if the release lever doesn't lift the chime lever high enough at the hour to release the chime train. The remedy is to spread open the "V" of the lever.
Strike Train Setup
•Rotate the center shaft CW until the release lever has just dropped off of the tallest lobe of the release cam. This will be the hour release.
•Hold a finger on the time train if the anchor isn't installed so the center shaft stays in position.
•Install the minute wheel and hour pipe.
•Pull the hour pipe so the hour wheel disengages from the minute pinion and rotate the snail until the rack tail is in the middle of the 12 step. It may be necessary to free the rack by lifting the rack hook so the rack drops onto the snail. Reengage the hour wheel with the minute pinion and install the washer and E-clip for the minute wheel.
•With the rack still dropped onto the 12 step, rotate the strike train until the strike star wheel lifts and then just drops the hammers. Arrest the train with a finger on the fly fan just as the hammer drops off of the star wheel. Lift the rack to the "stop" position and allow the strike train to continue until the stop/warning pin engages the stop lever at the top of the rack hook lever.
•With a finger on the strike fan, lift the stop lever out of the way and install the gathering pallet. It should be positioned so the lift pin on the back of the rack hook/stop lever is in the middle of the indentation on the lobe of the gathering pallet.
•The gathering pallet can be driven onto the arbor but take special note if a bushing has been installed in the rear of the 4th wheel. If so, it will need to be supported or driving the GP onto the arbor risks knocking out the bushing.