Horology – Watch Cleaning 101

By Jack

We can’t live politics all that time, it will drive you crazy, so I have a few other hobbies besides writing…to keep me relatively sane. The following is about one of them, collecting and/or repairing antique pocket watches. I thought you might the like diversion, given all the carnage lately. I did this article for the National Association of Watch and Clock Collectors, Inc. today.

When I received this pocket watch (grade 208, c1900 Elgin, 18s) it was not running. See picture to left. By the rust and grime on the case my guess was it probably hasn’t worked for decades. The first task is to find out what’s wrong, then determine if it’s worth repairing or if it will become a parts donor.

You can follow along by opening the 2nd picture for a step by step view. I begin by removing the watch from the case and placing the movement in my wood watch vice. Next, I remove the hands with a puller, but not before I slide a piece of clear plastic under the hands and against the dial to prevent any accidents. I removed the dial by loosening 3 tiny screws located around the rim. You may notice a hole on the movement directly under the main spring barrel? Put a probe into the hole and push, this will release the mainspring tension. Some pocket watches may have a tab sticking out that your push in to release the spring. This is a must before removing the barrel bridge, otherwise you risk damaging teeth on the wheel train. Good thing I released the spring on this one, it was wound tight!

The next step is to gently and carefully remove the balance bridge, balance wheel and hair spring – emphasis on carefully! I grab everything with my non-magnetic tweezers, then I set it aside without stretching the hairspring. While this is a simple task, many watch jobs are ruined right here, because if that balance wheel or bridge slips, the next thing you know is the hairspring is ruined. To prevent such an accident it’s better to release the hairspring. Back out a small set screw on the balance bridge (aka balance cock) and separate the hairspring. This time I did that after I removed it, but it’s up to you – your choice.

It’s always a good idea to keep your plate and bridge screws secure from accidents. I use plastic bottle caps because they are color coded. Watch screws and other tiny parts are known to grow legs and run away and this helps.

Once the all screws are removed the top plate is ready to lift off – but, be gentle, don’t force or pry! You never want to leave traces of your work on watch metal, right? You’ll note this watch has a full plate and a full plate is a bugger to put back due to the limited visibility and all the pivots that must be lined up. But, don’t worry there’s a trick I’ll show you later how to make this process fairly painless.

Now we’ve removed the top plate and you’ll note that some parts will stick to it and some will stick in the pillar plate…so, remove it slowly, knowing this could happen. Then take a good look before you put the top plate away and see what’s stuck. You want to remember how it all came apart, right?
Once we’ve stripped the movement down to it’s parts, a visual inspection with your loop will determine if you have any jewel issues, broken balance staff, etc. This is the time when you want to pop open the mainspring barrel. On some pocket watches you may have to remove the ratchet (gear on barrel) before removing the barrel and bridge, but not on this one. Be cautious not let the mainspring come flying out – if you do – have fun putting it back. Note the square tab sticking up from the mainspring at the wall of the barrel? This tab is to keep the top part from slipping on the barrel, so sure you match the notches on reassembly.

After my visual parts inspection I did not note any defects, they all looked remarkably good, save for being dirty. Lucky me, because half the time when it’s a non-runner it has a broken balance staff or a broken jewels.

I place all my parts into a basket and head for the sonic cleaner, this includes the stem and knob (onion). Some watchmakers will use circulating washers, but the inexpensive sonic works well enough for me. The worst cases just get extended time in the sonic. But, they are come out extremely clean.

I set the timer for 5 minutes and use a special sonic bath detergent solution. I would never suggest you use household detergents because they could cause stain or corrosion damage.

NOTE: Don’t put the dial in the sonic bath! Most of the time it will work fine, but sometimes if there are hairlines you could life out the porcelain (or white glass). If you do it’s not the end of the world, but I’ll address dial repair another time. I prefer to soak the dial clean to avoid and damage.

After a few minutes in the bath the parts look pretty good. Now comes the rinse. Try to keep the water temperature the same in the bath and the rinse, somewhere around 120 degrees Fahrenheit or 48 degrees Celsius. The warmth helps loosen debris and speed drying. Once rinsed off lay out the parts, wipe with a paper towel and then use a blow dryer, just don’t blast them off the work area. The blow drying heats up the parts to remove water from areas you might miss.

I used peg wood for the final clean up of all the holes in the plates and bridges, just get them all, doesn’t matter if they are bearing surfaces or not. Be sure to inspect the wheels with a loop. An antique watch is prone to having virtually baked on oil. If that happens you may have to soak them in a penetrating solution and then put them back through the bath process. Now you want to Check each wheel for end shake, side shake, upright and depth within its respective pinion. If all checks out and you’ve done your peg wood, congratulations you’ve done a proper cleaning job and you’re over half done!

Now comes oiling, and not just any oil will do. I use a specially formulated watch oil from China and I would tell you the name of it if I could read Chinese. Just use
watch oil, motor oil won’t do. And apply the oil sparingly with an oiler if you have one. I use 4X magnification for this process and an oiling pen that applies just a dot of oil when the pen is pressed down. Over oiling is a common mistake by amateur horologists. (See diagram).

Reassemble, checking for ease of movement as you go, and make sure all the parts go back in the reverse order. Now here’s the trick I mentioned earlier. I fit the pallet into the top plate and secure with 1/16″ painters tape (releases easy) and pull the ends around the plate. This does two things, it angles the pallet to provide clearance as drop in the center wheel. When removed it drops down to fit easily against the rollers. It also keeps it from falling out when you flip the top plate over for mounting.

Now the top plate is in position, but loose. I insert the plate screws, but only loosely to allow the plate a little play. Now I lightly push one the wheel pinions so their
axles/pinions will line up with the holes. A full plate requires a little more patience than other types in order to get those holes and pinions lined up, but the tape trick helps. Now check over the holes, check for movement and if all is well, now you can tighten up the plate screws and reassemble the balance wheel/bridge and your almost done. When you’re done soaking the dial, you can finish up.

For collector value I usually don’t recommend you polish a watch case because you’ll reduce it’s value, but if that is not your first concern, have at it. This particular pocket watch is made of Silverine, (it’s not silver, it’s an alloy) and it has some serious dirt and grime issues, as well as one nasty rust blemish on the back. I can’t send it back out in public that way, so I’m going to detail the case.

A mild cream metal polish and a high speed buffing wheel works wonders to remove years of abuse and dirt. After I gently buffed the case I discovered this watch case has none of the usual striations, dents or dings found on a carried watch of this vintage. The crystal (Lexan) shows perfectly too, even the bow fit’s snugly and the dial is without any hairlines fractures. Wow, this is unusual and I am thinking this watch was hardly exposed to any wear whatsoever. After buffing the case was put through the sonic wash and then heat dried.

Once this old Elgin is all back together it looks great! It shows virtually as new, what a nice surprise! Take a look at the final picture and see for yourself. This is a 112 year old Elgin and it’s purring along like a kitten now.