Sunday, June 16, 2013

For A Few Dollars More - Part 3: Cleaning

Once a movement has been taken apart, it's ready to be cleaned.  While modern professional watchmakers use ultrasonic cleaners that run automatically, it's also possible to clean the parts by hand.  The Army put out a Technical Manual in 1945, TM9-1575, which describes stringing the plates and bridges of a watch on dip wires, which are then dipped into the cleaning solution, and sloshed around.  When I started working on watches, I used to put the pieces in two tea strainers - one with somewhat coarse joints for the plates and bridges, and a finer  one for the small parts.  I still ended up having to carefully pick small parts like unset cap jewels and small springs off the edges of the wet basket!

Although the Technical Manual describes a 'homemade' solution for watch cleaning, it is water-based, and since many parts of a watch are polished steel, NOT stainless, rigorous attention must be paid to rinsing in an organic solvent that will displace the water, and then to thorough drying.  I took advantage of large, fan-driven incubators at work to dry watch parts after they'd been carefully laid out on paper in improvised trays.

Last year, I was able to obtain a L&R Master watch cleaning machine, with 3 jars, which needed only to have one wire resoldered, and a new light bulb to work.  It has made the whole process much better!  More on that in a bit.

First, if you recall, I'd discovered that the center wheel bushing in the barrel bridge was worn.  A professional watchmaker would be able to press out the old bushing and press in a new one, all in a few minutes.  Since I don't have a jewel press, I must make do.

I have a supply of parts movements, but none of them is a 642.  However, the 554 is nearly identical, using nearly all the same parts.  I checked in the Elgin Manual to see if any of the different parts were likely to cause problems.  One that gave me pause was that the 642 uses a different barrel and barrel cap than the 554 - odd, since it uses the same barrel arbor and mainspring!  I was concerned that the barrel might be bigger in the 642, and if so, the barrel bridge from a 554 might not fit. So, I carefully measured the height and diameter of the barrels of both the 642, and a 554 I'd previously disassembled, using a digital micrometer.  They are the same.


So, I looked through my parts movements till I found a 554 with a good center wheel bushing, then stole the barrel bridge.

Nice and round!  With that in hand, I loaded up the cleaning basket of the L&R.  In the main section, I put the plates, the plate screws, the minute wheel clamp, the barrel, cap, and arbor, and the stem - large heavy pieces I prefer not to have bouncing around the more delicate parts.

Next, I put the balance jewels and the easily-lost springs in the small, screw-top mesh basket.  This is where I also put any tiny screws, cap jewels, and the dial washer, if any - essentially anything I worry might get lost!

Finally, I put the rest of the parts in the recesses of the top of the basket - the pallet in the smallest, with the pallet bridge screw;  the balance all alone in the second-smallest; the winding/setting parts and the hour and minute hand from the dial side in the second largest, and the train, crown wheel, and click and accompanying screws in the largest.

The lid is paced on carefully, then the whole basket is attached to the spindle of the L&R.

The whole motor head is lowered, so the basket goes into the cleaning solution  - Zenith Waterless Watch Cleaning solution, in this case.  The knob is used to turn on the motor and set it to a fairly low speed.  Every 30 seconds, I reverse the direction to break up the flow, for better cleaning.

After 3 minutes, the basket is raised above the level of the fluid and spun to remove the excess.

The process is repeated in the next two jars, which contain Zenith waterless rinsing solution.  Over time, the cleaning solution gets darker, and the first rinse gets cloudy and accumulates a residue from the cleaning solution in the bottom.  I discard the Cleaning Solution and Rinse 1, transfer Rinse 2 to Rinse 1, and put new solutions in Cleaning and Rinse 2.

Once the parts have completed Rinse 2, it's time to dry them.  The 4th station is a sort of chimney with a big, heating resistor at the bottom.  The lefthand switch turns it on, and the pilot light tells you it's on.  The basket is lowered into the chimney and run at a slow speed for about 5 minutes.

After letting the basket cool for a few minutes, it's time to finish the cleaning process.  "Wait", I hear you thinking, "I thought the parts would be clean now!"  Well, they're cleanER.  There is still some residue of the old oil and other schmutz that must be carefully removed for the watch to run at its best!

Here you see my bench, laid out in preparation for the final stages of cleaning.

Clockwise from the upper left:  Movement tray with fresh blob of Rodico; Movement holder, brush, tweezers and Pegwood, Pithwood and razor for sharpening Pegwood, and the basket full of clean watch parts.

The Pegwood is used to scrape the oil residue off of jewels and to remove it from the jewel holes - essentially polishing the jewel and removing everything from the surface to keep the oil in place - dirt will allow it to spread.  One end is sharpened to a point for cleaning the jewel holes, the other to a chisel shape for scraping the flat surfaces.

 In the background is a pithwood disk.  Pithwood is the center of branches of the Elder tree.  It is about the consistency of styrofoam, and it has a mild abrasive action when you plunge steel pivots into it.  This removes the last vestiges of oil residue from the pivots and jewels, leaving them perfectly clean.  It's also used during assembly to clean tweezer and screwdriver tips, as well as to clean oilers.

I push the balance, roller jewel-down into the pithwood to clean both the pivot and the jewel, then flip it over to clean the upper pivot.  Obviously this is done with care to avoid distorting the hairspring.

I do the same with the pallet pivots, and all the train wheels.  At this time, I also check the pallet jewels for any residue on the impulse face.  If there is any, I LIGHTLY drag the jewel through the pitwood to remove it.  Sorry there are no pictures - the trick is to hold the pallet at just the right angle such that the light reflects off the impulse face, while observing through your loupe.  Hard to get a picture of that!!!

This is also a good time to inspect the teeth of the wheels, and the leaves of the pinions.

Next, the jewels and bushings are pegged.  Here again, you use the reflection of light on the surface of the jewels to show you where the dirt is.  Check out the left hand cap jewel.  You can JUST see the schmutz on the surface.  This must be removed!

All the pivot holes on each plate and bridge must have their flat surfaces rubbed clean, and their pivot holes polished with the pointed end. The pointed end is gently pushed into the pivot hole while twirling slightly, and pressure is slowly increased.  When you pull the point back out, the tip should have a long, pointy bit where it went through the hole.  If not, you might have just plugged the hole, and you'll have to resharpen and repeat until you've cleared the hole.

 Both the chisel and the point should be resharpened frequently.  Each jewel should be inspected with your high power loupe, with a light background to ensure the hole is clean and the surfaces clear of dirt, dust, and any wood fibers.  The residue and wood fibers are easily removed with Rodico, which is also useful for cleaning off fingerprints.

In addition to cleaning the jewels, Pegwood is also useful for scraping residues off other parts, in this case dried grease from the inside of the barrel cap. 

Now that all the parts are scrupulously clean, and laid out in the movement tray, it's time to start reassembly.  That's for the NEXT post!

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