There is a sequence of things to be accounted in the process of setting a tower clock. Far too often I see public clocks with several dials, each reading a different time. Since I don't want to play the odds on which dial to believe, I carry a watch, and the real purpose of the tower clock is lost to everyone.
I do not much practice in situ repair of tower clocks. I have an allergy to avian dung which manifested itself a few years ago during my short career as an egg farmer. I leave the work required to be performed in consecrated dove cotes to hardier souls, although I am often called upon to repair or fabricate parts for tower clock movements. Disclaimer aside, I have, over the years, come away from the tower clocks I have attended with a little more than just pigeon feathers stuck to my shoes.
Unless there are reliable pilot marks visible on the components of the drive shafts and motion works, or the dial hands outside the clock room can be seen through doors existent on some large dials, it is difficult to align the hands without an assistant. The last clock I restored belonged to a municipality, so I asked the authorities to provide me with an agile policeman and a pair of walkie talkies. Once we were able to agree on the directions right and left, I loosened the set screw available at the dial end of each of four universal slip joints, and moved each set of hands to 6:00 o'clock, then tightened the set screw. When my helper could tell me each pair of hands read six o'clock, I was ready to actually set the clock.
I should mention, however, that if there is significant disparity among the sets of hands, or if the hour hand doesn't align with a designated hour when the minute hand is at the "12" mark, correction of this may be accomplished by loosening the minute wheel on the motion work, pulling it back so that the hour and minute gears are independent of the minute wheel. Normally the means of attaching the hands to their respective shafts is fixed at the factory, so their proper alignment is within the correct positioning of one gear to the other. Unfortunately, not every minute wheel is easily disengaged. In those circumstances, it may be necessary to actually disconnect the inside linkage and to remove the minute hand to effect a correct relation between hour and minute hand. Sorry to have to tell you that. It may now be time to call for the services of a steeple jack, and a large can of Mystery oil for purposes of loosening the nut on the minute hand, or even the screws holding the hour hand to its boss. Since the hands, often the dial, and probably the building are wood, nix the blow torch approach to loosening anything.
During all of this operation there is the further complication that if the clock is a striker, or equipped with chimes and strike, the movement must be set exactly at six o'clock, with the chimes coordinated, and the strike snail properly positioned before the exterior hands are set and locked to the movement. Be sure too, that the setting dial is set at six o'clock at the same time other settings are made.
Now that the workman has assured himself that the tower clock hands are all coordinated, and all the setting and adjusting screws in the linkage from clock to hands are tight, it is time to set the hands. Numerous early, generally hand-made tower clocks, and a few factory made clocks such as those of George Stevens in Boston, are set by disengaging the pallets. Ordinarily these clocks were made with extra long pivots on the pallet arbor, and there was a hinged plate, like a removable end stone, to hold the pallets in place.
To set the clock, the operator pulled the stop plate out of the way, then slid the pallets out of engagement, all the while restraining the escape wheel with his fingers or a piece of wood with a V notch cut into it and applied to the scape wheel arbor. The escape wheel is allowed to spin down, but at a controlled speed using either fingers or the notched wood. Almost every tower clock has a dial attached to the movement showing what the hands on the outside dials read. By watching this dial, the workman knows when to stop letting the escape wheel spin down, and to re-engage the pallets. Things did not always go as they were intended, and I have cut or re-cut several such 'scape wheels after the teeth were milled away by the pallets.
In time, cooler heads prevailed, and clock manufacturers devised more practical ways to set the hands. Both Seth Thomas and Howard, the largest manufacturers of public clocks in America, used a system involving a spring loaded pin. I do not know the name used generally for this part. I have a set of Howard #3 striker blue prints, and, without looking, I think it is called "setting pin." A more creative name would only lead to confusion. Over the years I have called it a "bull pin" because it works the same as a device of that name used to disengage the pulley from the shaft on engine lathes when the back gears are engaged.
Setting the hands on clocks equipped in this manner is the essence of simplicity. There are sixty holes in a plate which is positioned against the 2nd wheel (which is the center shaft turning once pr. hour) and the plate moves independently when the setting pin is pulled back. The plate and its attached bevel gear can be turned until the setting dial reads within a minute of the correct time. Where there is a need to set the clock precisely, it is best to set the clock one minute ahead, then the 'scape wheel can be held until the right moment, when it is released. When doing this, however, be sure the escape wheel is held so that the pallets do not crash against a tooth of the wheel with predictable bad results.
There are probably several additional ways to set tower clocks, including stopping them until the hands read the right time. Most clockmakers were smart enough to avoid that option. On some, especially smaller tower clocks, the hands can be disengaged by a slip joint somewhere in the linkage. Usually, then, there is a setting dial in the clock room remote from the movement.
I have seen an English tower clock movement with an adjustable friction clutch which permitted the movement to drive the hands, and the hands were set by turning the drive shaft to the right time by force greater than the friction which drives the hands. This system, at first blush, looks like a case of playing with wind and ice. On second thought, however, it serves to protect the clock from the damage of having a gust of wind reverse the torque of the movement so drastically that the escape wheel is damaged.
On very small "tower clock" movements, as found in sidewalk clocks for example, setting is accomplished just by loosening the set screw on the bevel gear attached to the center arbor. Here, there is no problem seeing the hands on the dial above the movement.
There is, of course, one final requisite to setting a tower clock. Begin by knowing the right time. Jcl
John C. Losch
Holliston, Mass.
© John.C. Losch, Reproduction without permission prohibited , except for personal use.
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