Clocks

Gratitude – clock oil

Some mechanical clocks are regulated by pendulums. Those clocks can’t be wandering around. The pendulum must swing an equal distance to each side of a center line that runs through the escapement. That center line needs to be plumb and fixed so it doesn’t move. This requirement makes the back board the most critical piece of the clock case. Not only does the back board hold the movement and chime rods in place, it also needs to provide a way for hanging the case on the wall and keeping it fixed in place. Here, we see the back side of the backboard.  A through hole on the center line near the top of the board is the single hang point for the case. About two-thirds the way down the line is a slot which fits snugly over a screw head protruding from the wall, keeping the case from wandering.

Keen observers will note two such slots. The first slot is the result of one of my pet peeves: measuring instruments have far too many marks on them, leading to errors. The second slot is the one I’ll actually use.

The board is cherry faced plywood (ouch it hurts to use that word / stuff). It is wide enough to be concerned about movement, so I relented to using plywood. It is drilled with 3 holes along the top edge and 3 along the bottom for fastening the board to the rest of the case. The four larger inset holes are for mounting the clock movement. Insetting whose holes keeps steel nuts from scraping on a wall. The four smaller countersunk holes are for mounting the chime block.

Only a couple of companies still manufacture mechanical clock movements. This one is by Hermle. It has three trains. Left to right (see the square winding pegs) they are: the hours chimes, the time, and the 1/4 hour chimes. Both chime trains are spring driven. Note the spring holding cylinders behind the winding pegs. The time train is weight driven, providing a steady source of power that does not vary as a spring might. Thus, a well regulated clock.

BTW, the spring for the 1/4 hour chimes has the yeoman’s job and is much heavier than the spring for the hours train. That heavy spring could probably be an alternate power source for when Tesla decides to quit making coal-powered automobiles.

In these pictures, the back board is positioned in my bench vise so that it is level across the top, making the center line plumb. The movement is also mounted so that it too is level across the top. …and yes, the clock was running, making the pendulum look off plumb, because it was swinging.

The chimes are copper rods set into an iron block that is positioned so the chime rods are about 1/8 inch from the tips of the hammers when the hammers are “at rest.” A spacer block completes the positioning of the chimes rods.

I set it up this way to test the works, while they are not obscured by the case. This movement has been sitting unused in storage for at least three years. Upon setting it up, the 1/4 hour strike train ran very very slow, taking about 2 seconds to strike a single note. I put the pendulum in its hanger, set the escapement for an even beat and let it run overnight, hoping that some run-in would free up the slow parts. Didn’t happen. Having some clock oil on hand from previous clock work, I sparingly oiled every pivot. That worked. The chimes are now running at full speed and the time train is also running smoothly.

The escapement consists of the pendulum and a pallet bar that controls the turning of the escape wheel. The pallet bar can be adjusted on its shaft to produce the correct action, and that action is noted by a very even beat between the ticks of the pallets striking the escape wheel. This video show the setting is pretty close, maybe not perfect, but close enough for initial testing.

Next, we have the nicely running chimes.

Before long, I’ll take all the pretty stuff off the back board and put it safely aside so I can continue building the rest of the case.

Drop one of these. (approx 1/4″ diameter)

Sweep up carefully…

While listening to this…

{ Yes, I found it.  Note euphoria  4:49 – 5:07. }

Gratitude – patience is a virtue

“Assumptions are dangerous.” “Times change.” Both are favorite sayings of a professor I once knew.

I just assumed the great glass shop down the road would still be there waiting to make glass for me. I printed out my plans and drove down. The shop was closed, and by the looks of the peeling paint had been for awhile. Best I can surmise, the owner retired. So… I drove around to a few other shops I knew of around here; closed, closed, closed.

The glass I want is custom cut, circular at the top, rounded bottom corners, and the piece for the door has beveled edges. See that nice 1 inch bevel? The store I used to frequent could do almost anything, and I assumed (there’s that word again) that other glass shops could also do the same sorts of work.

Like so many other businesses, the local shops are disappearing. OK, online it is. After all, I’m a web geek! Oughta be able to find what I want. Bzzzzzzzzzzt! Dozens and dozens of searches for custom cut glass, for beveled glass, for “glass & mirror” (not auto glass) resulted in 8 places that seemed feasible. The one with the most advertising money [their ads started immediately appearing on almost all web pages] had a simple 3 word answer “can’t do it.” Three others didn’t answer at all. The rest said things like:

• “Our bevel machine is down.” {and no, they don’t plan to fix it}.
• “We can only bevel straight edges.”
• “Can’t do the bevels.” but offered a bid on completely different sized pieces of glass.

Then it hit me. Go back to that clock collector forum I followed years ago. There I discovered that there are two makers of custom clock glass still working. Bingo!  Ahem, don’t get too excited yet. One of those guys doesn’t answer and the other has moved.

I did manage to connect with one of them. He can make exactly what I want. BTW, he does all beveling by hand, and lo and behold, a beveling machine is just a big belt sander used by a skilled craftsman. I placed an order, and he responded with “Hope you don’t need it before Christmas.” He has a 2-3 month backlog.

… to be continued.