And so

Returning to Nana's clock...

Reported in our last episode on the topic was the concerning issue of the mainspring pressing up against the shroud of the lantern pinion of the second wheel.

Still a mouthful.

There were several questions in diagnosing the problem.

Firstly was the question of the "missing" rod.

From my earlier post:

Inside view

outside view

Is there supposed to be a rod D?

There's a rod A which helps the strike train mainspring expand / deflect effectively. 

Why is there no D rod?

Is the challenge based on some kind of anomaly in Seth Thomas manufacturing?

In short, no.

This researcher found several photographs of other clocks with Hip movements and none had a rivet indicating a rod D.

An example:

OK so we know this was not a manufacturing error.

In the 1902 effort of swapping over the Seth Thomas Hip movements in Adamantine clocks with the next generation "89" movements did that include a benefit of adding a rod D?

Nope.

The 89's don't have a rod D either!

I'll spare you the pictures. Trust me. I looked.

So Mr. Seth Thomas didn't think they were essential for the clock movement.

Hmm...

How about other makers? Did they have D rods?

Well... some yes, some no.

Here's the movement of a recently acquired Gilbert Mission clock.

No D.

Then there is an Ingraham that your correspondent dug up some 4 years ago.

This model took a cheaper approach to mainspring deflection by pushing out stubs from the plate brass. Probably more cost effective.

But there are four stubs, a pair for each mainspring.

The one on the upper left is effectively a D.

Ergo some clockmakers employed a D and some didn't.

Thereby implying that it was deemed unneeded by many.

Why?

Why!

Gah!

OK... I'm better now...

By the way. Go take a look at that example photo posted above of the other Hip movement, the one marked "nada."

Go ahead. 

I'll wait.

...

See anything funny?

Nothing?

Look at the time train mainspring.

I'll wait.

...

Did you see it?

No?

OK. Here's a close up.

The mainspring is hitting the shroud of the lantern pinion!!!

Absolutely no mention of any problem with that though.

Is it supposed to do this!?

Gah!

If the D rod was not needed then what was the expected behavior of the time train mainspring as it expanded?

Was it supposed to just hit the shroud and deflect? The shroud is round...

That was the topic of your correspondent's further explorations of our conundrum.

And search he did.

And searched some more.

This internet detective could find nothing about a mainspring:

colliding with

pressing into

bumping into

hitting

expanding into

abrading

touching

incorrectly deflecting into

annoying

... a wheel / lantern pinion shroud in a movement.

Your despondent correspondent was about to give up.

But finally...

Like a dog chewing a bone...

This relentless researcher found something.

This clock fool unearthed a post on the NAWCC message board (of course).

In a lengthy but typically generous response to a query, a master clockmaker and a regular contributor of clock wisdom, R. Croswell, said that the mainspring hitting a wheel can be remedied by a careful cleaning and lubrication.

Did that already.

And low and behold another post, about a Waterbury clock movement demonstrating exactly the same problem.

There are about 1 bazillion posts on the NAWCC message boards and it turns out that the term I needed was... 

"rubbing"

And on that thread, another master clockmaker and a constant contributor of clock wisdom, Willie X, said effectively...

If the clock runs a week or more and then it hits the shroud... don't worry about it.

Really?

Well your local horologist believes that the designers of this movement (and likely others) believed that the shroud would/should defect the mainspring if required to do so.

And gang... the clock does run for 8 days before this happens. Nana's clock runs great for over a week and that is the intended running time before rewinding.

Zo...

The mainspring was lubricated again including the outer edge that rubs up against the shroud. 

Maybe that will help deflect it if required in the future.

The movement was put back in the case.

YLH doesn't like to overly restore cases and finishes but I did clean her up a bit and gave the dial bezel a touch of polishing. Just enough to let some more of the natural beauty come through but not lose all the grace of her wrinkles.

Nana's clock runs great and I'm giving her back to Ted. It's been a pleasure.