This time...

...friction was not our friend.

In our last episode your local horologist had the Thomas Adams Astro Regulator English Bell Strike up running on the Johnson Arts test stand. 

For a few minutes.

Until it stopped.

Earlier in our adventures with this fine clock YLH had referred to the occasion where friction was missing and needed in the function of the friction fit of the anchor arbor. More often friction is a source of trouble and excess friction is typically the single most common reason for a clock to slow / stop. 

And your clock doc suspected that unwanted friction was at play here.

But where?

Boy howdy can that be a long fishing expedition. 

You see gentle reader there are so many parts in a clock that engage, slide along, mesh, bind, press, rub against... one another. 

But there are the more common sources of friction that can rob power from a clock and your plumber of horological depths had a couple ideas right from the jump.

One was the suspension bridge. 

This guy:

What? 

How?

Yes it has gone through quite a few nips and tucks as well as a full face lift but how might this create unwanted friction?

With the attention this gizmo had already received YLH noticed something errant.

You see this suspension bridge serves two purposes. One, and from which it derives its name, is to suspend the pendulum off the back of the movement.

The second purpose is far less immediately visibly obvious but equally important.

Remember this view of the soldered friction fit?

Observe the anchor arbor. Like most arbors it runs from one plate to another with pivots on both ends.  

See how the anchor arbor starts on the right end, extending from a pivot hole on the front plate and traveling leftward (towards the suspension bridge). The left pivot of the anchor arbor doesn't sit on the back plate as do the pivots of all the other arbors. The anchor arbor travels through a circular cutout in the back plate and then into to that ugly friction fit with the soldering job on the left side. 

It doesn't quite end there. It extends just further to where the left pivot hole is found in the center piece of the suspension bridge, just to the left of the friction fit. In the view above its the strip of brass with the solder along the top and it has some kind of indentation in it.

Here is the birds eye view of the pivot hole on the suspension bridge as the pivot end would enter it.

Yeah there's a lot of extra solder there. It looks like the brass had badly deteriorated above the hole and a larger soldering effort was made to repair it. 

Sorta.

Oh and that view there... that was after this cleaner of clocks took a stab at it.

Here's how it appeared earlier, right after first disassembly:

And here's another birds eye view from the opposite side (pre-cleaning).

See how the pivot hole appears just under the base of the suspension cock?

Yeah that ain't pretty in there. That pivot hole appears to have excess solder inside the hole.

Yipes.

And the most voracious readers of our missives might recall this earlier illustration of the anchor arbor and the pivot that seats in our crusty pivot hole:

Yes that pivot is bent which would be a source of friction in itself.

And furthermore ...

Well... let's first look at the opposite pivot. The pivot on the other end of the anchor arbor that seats in the pivot hole on the front plate.

YLH gave that pivot a bit of a clean but it was in pretty good shape so this serves a reasonable example of how pivots should look.

That pivot is straight, clean and relatively smooth all around (especially after YLH burnished it a bit). Here is a fine treatise on practical burnishing by NAWCC genius and generous publisher of things horological Dave LaBounty. 

Pivots can often badly wear from the materials in the pivot holes (dirt and other things) creating grooves and cuts and worse.

Our pivot above looks pretty good.

Mr. LaBounty also offers examples of burnishing efforts from serious horological metalurgists who might admonish this horology hack that our example above is too far from excellence.

Whatever.

You see dear reader our other pivot... 

The one just next to the friction fit... 

The one that was bent...

Was also a bit... 

Rough.

Oy vay.

See all those tiny grooves cut into the barrel of the pivot? That is probably from the excess solder sitting in the pivot hole scraping away at the pivot as it swings back and forth with the anchor and pendulum.

What cause the bend? Who knows.

But that was a sad pivot.

Zo... VERY gentle straightening ensued (get that wrong and you have a much bigger repair to do).

Cleaning, burnishing and a minor religious conversion later...

It'll do for horseshoes and hand grenades.

The bigger problem was the pivot hole itself. The one with all the solder crust in it.

Fortunately this horological hoarder had weapons (files and burnishers used for clock bushing) that would help clean out that pivot hole.

The burnishing rods effectively act to smooth out the rough effects of filing. Carefully worked with some clock oil as a lubricant.

WMDs were kept in abeyance.

Cleaned up pretty well.

And here is the refurbished pivot protruding from the refurbished pivot hole.

This improved things considerably.

A light reassembly and a run on the test stand.

Hey it's running!

Like for more than 5 minutes!

Actually it ran overnight.

Yes!

Ready to go?

Are we done?

Oh no young padawan. 

YLH wishes it were so.

There were still a few surprises ahead.