Basic watchmaking tips - Oiling Part 2 (the mainspring barrel)

This is another installment in a series of watchmaking tips – previous threads can be found here:

https://omegaforums.net/threads/basic-watchmaking-tips-cleaning.56365/#post-696021

https://omegaforums.net/threads/basic-watchmaking-tips-oiling-part-1.62310/

So I want to continue with more information on oiling techniques. I do suggest referring to technical guides from the manufacturer when selecting the type or weight of oil to use in a given situation. Even if you can’t find a technical guide for the specific movement in question, using a guide for a similar movement can help you decide what oils or greases to use for a given application. For the most part though, slower and higher loads require a heavier oil, where lighter and faster loads will use a lighter weight oil.

I started writing this post intending to cover a few parts of the watch, but once I started there seemed to be a lot of information I thought I should include, so it ended up being just about the mainspring barrel. In a manual winding watch, the primary lubrication points are where the barrel arbor fits into the drum and cover of the mainspring barrel. An automatic barrel requires a bit more, so in addition to the lubrication on the barrel arbor where it rides on the barrel drum and cover, the inside wall of the barrel will get a special grease applied – this is braking grease. As the name suggests this grease brakes the slipping of the mainspring inside the barrel in order to prevent the spring from slipping too much as the watch is being wound. The grease I use most is Kluber P125 Kronogrease, and it’s a black grease that is very tacky. There are different ways of applying grease, but I was taught the method shown below and since I’ve not heard a good argument to do it otherwise, this is how I grease mainspring barrels. I use a sharpened piece of peg wood inserted in the hole for the barrel drum to hold the drum, and then use my oiler to scoop up a small amount of grease from the oil cup, and then I smear a very thin layer around the inside of the barrel wall:



The a mount of grease doesn’t need to be huge, and applying too much can cause problems like rebanking (too much balance amplitude) so it’s just a thin layer on the wall of the drum, placed in the middle of that wall. Because the grease I use is black (opaque) it's difficult to see but this layer is very thin. One thing to make sure of is that there are no globs or small “tails” of grease sticking out from the wall, so make sure you turn the barrel to look inside straight on like so:



Now from here the mainspring is installed, and for that I simply lay the barrel drum on my barrel closing tool, and lay the new spring on top. I make sure the spring is centered in the barrel, and use the back end of my tweezers to push it down flush with the shipping ring, and then hold it there while using the small brass tool on the right of the photo to press the spring into the barrel:



Then the barrel arbor is lubricated with oil (in this case HP1300) and installed, then the barrel cover is installed and I carry on. Just to note that anyone out there who reads this section and says “That’s not how Omega says you should apply the grease in the barrel!” yes you are completely correct. Omega recommends applying several dabs of grease around the barrel wall, but knowing that this grease will eventually get spread out anyway, I just do that ahead of time. While attending training at Omega a number of years ago the instructor checked our work often, and when we started on the barrel he specifically told everyone in the class to just grease the barrel the way you normally do, and then let him see it. I did it this way and he said it looked very neat and was completely fine with him.

Now some mainsprings have plenty of clearance when you press them into the barrel, but others do not – in those the diameter of coiled spring in the shipping ring is very close to the inside diameter of the barrel drum. If you have those tails of grease sticking out, use too much grease, or don’t have the spring centered when you press it in, this can lead to grease getting to places it doesn’t belong – sometimes the grease gets pushed to the bottom of the barrel drum. This example illustrates what too much grease looks like after a time – the grease has spread to the bottom of the barrel drum, and the underside of the barrel cover:



The excess grease you see here can cause a shorter power reserve because it is now causing drag of the mainspring in the barrel, and this may cause the torque to drop off sooner than it would if that wasn’t there.

What about lubrication of the mainspring itself? Well that depends a bit on the spring you are using. I typically replace mainsprings when I service a watch – it’s good practice and what all brands do at their service centers. If for some reason I can’t find a new mainspring for a given watch (this can happen sometimes with an old pocket watch that has an oddball end design) and I want to use a spring over, the first thing I do is clean it in the cleaning machine. But before I get to the cleaning, let’s talk about when not to use a spring again. Here is an example of a spring that one might consider using again – it looks like it’s in decent shape:



But you should always carefully inspect the spring, and the first step in that is laying it on a flat surface, and seeing if the spring is flat – this one is not:



You can see a spot where the spring rises in the middle, and there is also some smaller gaps to the bench in other places. For me this is enough to warrant not using this spring, because if a spring is bent too much, it can rub on the floor of the barrel drum of underside of the barrel cover (loss of power). I also visually check the spring for any cracks, nicks, make sure it’s not set, and even run it through my fingers and feel for any waviness in the spring. If anything is not perfect, the spring gets tossed.

Note that I will virtually always replace an old blued steel mainspring, because they have not been made in many decades and the stock that is out there is often brittle and will break easily. In fact, some break while still in their original containers, like this one:



So just to illustrate what a set spring looks like, this is a Panerai I serviced a while back, and note the shape of the spring:



Now here is that same spring next to one I removed from another Panerai I was working on at the time – you will note that the proper spring on the top is shaped like an S, and this is what modern alloy mainsprings look like:



So the previous watchmaker had really made a mess of this watch, and the mainspring he used was not correct for the watch – wrong dimensions and as you can see it had been crudely heated and modified to work:





In addition, it looks like that same person was very rough installing the spring, and gouged the crap out of the barrel drum:



I had to replace the barrel because of this damage:



So also make sure you check the condition of the barrel itself – make sure there’s no obvious damage like the above, and that the barrel is not worn excessively as well. For wear I check all surfaces, including the side shake between the barrel arbor and barrel, and the also on an automatic barrel pay attention to the barrel wall. In this Rolex the barrel on the right I had to replace because you can see the sliding spring going around and around for likely decades without service has worn a deep groove in the wall of the barrel drum – the one on the left is unworn and has no such groove:



You should also look for damaged teeth on the barrel, in particular if the watch has a broken mainspring, like this one did:





Also make sure the barrel is not warped, dented, or otherwise damaged:



So back to cleaning – after running it through the cleaning machine, the cleaning is not done at that point. It needs more cleaning so here are the tools I use:



Nothing fancy, so some 99% alcohol, watchmaker’s tissue paper, and tweezers. I tear off a corner of the paper, soak it in alcohol, wrap it around the spring, and grip the paper with my tweezers:



Then I pull the spring through the tweezers while gripping it with the paper – you can see some dirt on the paper:



I keep repeating this process until the paper comes away 100% clean. I then tear off another small piece of paper and place a drop of appropriate oil on it:



I then again wrap that around the spring, and pull it through the oiled paper:



But that’s too much oil – so I take a clean piece of paper, wrap it around the spring, and this time very lightly grip it and pull the spring through:



That’s it – the spring does not need any more oil than the very thin film that is left on it. Too much oil can cause problems, like when it mixes with the braking grease and changes the properties of that grease. It can also cause the coils to stick together, again causing problems with the way the power is delivered to the movement. I know many have probably seen or been taught that you place 3 or 4 drops of oil on the bottom of the barrel drum before inserting the spring, or on top of the coils after installing the spring in the barrel, or some other similar technique, but it’s really not needed. I often open up mainspring barrels only to find the mainsprings swimming in oil, and sometimes the oil comes out through the hole in the barrel and is found all through the movement – you simply don’t need this much oil:



Once the spring is cleaned and oiled, you should install it using a proper mainspring winder of course.

So do you need to oil new modern alloy mainsprings? Generally the answer is no, but I’m sure there are some exceptions out there that will need it. Most new white alloy mainsprings are coated with a dry lubricant, and do not need any oil applied to them. This is often difficult to see, but every so often I do see it on a new spring – for example on this Omega spring that I installed into a barrel, you can see some white material on the spring, which is the dry lubricant:



And on this one it is slightly blue in colour:



So that pretty much covers the lubrication of mainspring barrels. I will mention though that there are some special cases, like sealed mainspring barrels:



These were a trend at one point and the idea was that when the watch came in for a service, the entire barrel would be replaced. Now some of these can be opened, and new springs installed, but how difficult that is depends on the design of the barrel drum and lid. The Bulova barrel above was fairly simple to open and close back up again like a regular barrel is. However on some watches the lid is more or less crimped in place, so even opening them can cause damage. If you are lucky, some old stock barrels can be found for some models like this Longines Ultrachron movement:



But others are far more difficult to find, such as barrels for many vintage Zodiac watches. In some cases using the existing barrel over again can be done, at least until a new barrel can be located.

Okay this post covered a small part of the movement, but quite a lot of lubrication and side information related to the barrel and mainspring, so I’ll leave it here. I wrote this post bit by bit over quite a long while as I had time, so hopefully it’s not too disjointed.

I do find that a lot of attention is paid to the balance by many watchmakers and enthusiasts, but when it comes right down to it every part of the watch is important. Unless you have a smooth and proper supply of torque coming from the mainspring (the engine of the watch) then a lot of the fine tweaking you may do downstream won’t be of much use, so covering this in some detail is important. As always if you have questions, please let me know and I’ll do my best to answer.

Cheers, Al

I wanted to be a watchmaker to save money on my watches. I joined the local Watchmakers assn., met a man I admired and asked if he would give me some pointers, let me help in his shop. He replied "take the 4 year course at Oklahoma State University, get a proper set of tools and we'll start from there".

I moved "watchmaking" from a trade to being a science.

My goals now are to change straps without screwing stuff up. Some day I may step up to crystals.

Quadrophenic-Schizophrenia (a marker for the future)

Amazing series Al, and thanks for explaining it all so clearly with good illustrative pics.

Mods, is there any way we can make Al's series an educational sticky?

Or perhaps an educational subforum but I like the idea of a sticky if we can keep it from getting cluttered.

Excess lubrication is a common thing I see in watches that come to me after being serviced by someone else and having various problems. In particular the lubrication of the escapement seems to give many people problems. It seems many think that is a little is good, then more is better, but it doesn't work that way.

The next post I'll make on lubrication is going to be about lubricating train wheels and related items, and if that doesn't get too long, I may include escapements in it as well.

Most of the sub-standard work I see doesn't involve people having difficulties with complex tasks, but falling down on the basics - cleanliness and lubrication. Those should be easy things to resolve, but I see a lot who seem to struggle with them...

Glad everyone enjoys these - motivates me to keep going as they do require a lot of work.

Again if anyone has questions on the topic, please post them and I'll do my best to answer.

Cheers, Al

It may seems like a silly question Al, but is there any need to lube the barrel wall in a manual wind barrel?

And could you explain the mechanics of the braking grease. Does it hold the spring up to a point, and then let go but still provide lubrication?

Cheers

Jim

No - in a typical manual winding watch the spring hooks into a notch in the barrel wall. There are different systems for this, with various methods of connecting the outer end to the barrel (tang end, tee end, hole end, double brace and hole end, etc.), but these springs don't slip inside the barrel - connected at both ends. The spring is lightly lubricated, and the interface between the barrel drum/cover and the arbor, but that's usually all that's needed on a manual winding barrel.

There are different types of braking greases, but the type I use is very tacky. As the spring winds inside the barrel, it is being coiled around the barrel arbor. As more of the spring is wound around the arbor, eventually the outer end of the spring will break free and start to slip along the barrel wall. If no braking was applied to the wall, when the spring slips it would unwind too much, and the torque being delivered would drop off until the watch wound back up again. The grease allows the spring to slip, but not slip too far so the torque stays more constant.

Certainly the grease prevents some metal to metal contact, but it's not really a lubricant in the traditional sense, as it increase friction rather than lowers it.

Cheers, Al

Al, I just got through your latest post on oiling the wheel train and coincidentally I recently opened a mainspring barrel that showed the results of "more oil must be better" so I thought I'd post it under this thread.

Oil had even wicked out onto the plates and there were other oil stains where oiling had been overdone. Strangely enough though, the jewels on the main plate were practically bone dry.

The mainspring and arbor, showing the huge amount of oil (enough to lubricate the whole watch I reckon).

And after cleaning and oiling the mainspring (tweezers/watchpaper/oil) we have this.