I would like to replace a couple of case screws in a couple of pocket watches I have on hand here. Would this set provide the proper fitting screwdriver for the task?
I find on the older wrecked screws tend to tear up the nicely dressed screwdrivers. So I keep a set of cheap screwdrivers for working on them.
Over the years I have acquired different dressing things like @Archer showed. What works best for me is a diamond hone. Not unlike the small file shown. I do have the roller thingy. It is really easy to grind groves into the dressing stone. The bearings also get bunged up easy.
I also have a large slow wet grinder (from the enameling days) which I use for roughing things out. When I got the 21s century watchmaking book by W.O. Smith Jr. I Impulse purchased a crocker tool and motorized diamond lap (for graver sharpening.) There is no panacea that can replace in person mentoring and experience. I only ever used this fancy system once in nearly 30 years. Setting up the water cooling drip system is a real PITA.
While the fancy boxed sets with ergonomic handles are pricey. The replacement blades are not. The handles are also sold individually. These were common at the NAWCC marts and seem to pepper eBay. I suspect a lot of folk get them and find they are not magic wands. My favorites are some of the old ones that fit my hand well. This is another place where having someone watch to correct bad habits is probably a good thing.
One of my other fantasy projects is to make a dremel jig should I ever want hollow ground drivers.
One thing that was impressive on the factory tours, was how the drivers fit the screw so well, they could pick up the screws and place it with almost a single motion. That sort of skill can only come from in person training and a lot of practice.
I personally would like to know more about broken screw removal. The Alum works great when the metals differ. When one has a broken scres in a barrel arbor or chronograph bridge, such can not disolve out. And the bergeon 30209 tends to tear around the edge of the screw, or the points simply smashes. I found I had to make and dress my own points with mixed results. Barrel arbors are not drilled through so this style tool can not work.
Kano slikroil and Evap-O-Rust do seem to work. This dicolores the screw as they chemically convert the oxide.
Drilling is the last resort. The drill however tends to wonder. Micro endmills may be a better option they break when one looks at them. If drilling is done, such has to be in the lathe with a face plate. (I forgot this and attempted to use the dumore) PcBoard drills used to show up in the surplus stores. These also break when you look at them. Harbor Fright had some last week unmarked so out of tolerance rejects. These are designed to work in air bushings at 20 to 30000 rpm. Dremmels are simply slot car hobby motors with a chuck, so they are not really precice enough. The drill will alwasy bite into the soft metal surrounding the screw,
In production and warranty repair, it is much simpler to replace the part than fix it. Would like to know though if there is a better way?
Thanks Sheepdoll.
There have been a few occasions in the now distant past where my efforts at amateur gunsmithing had me employing a Dremel Tool. I always seemed to get a little too happy with the Dremel Tool and the dismal results were not a pretty sight. So, Dremel Tools are now outlawed on the gun bench. I shudder to think of me waiving a Dremel Tool around watches.
Oh, face it. I shudder to think of me working on poor defenseless watches at all.
I would like to tiptoe around the edges of working on watches: replace a missing screw, to regulate them, replace a crystal, perhaps even to remove a movement from its case and then to put it back.
Fascinating, thank you. You clearly go to enormous lengths to avoid damaging screws. When you find one is damaged, or even missing, what is your approach to replacement? Do many collectors ask you to source the exact screw as used in manufacture, do they ask you for an accurate substitute in terms of screw head type, or are they not bothered about this, and happy for you just to replace with a screw of the correct size?
Thank you for all of this excellent information @Archer! I have no desires to dabble in watchmaking, but do need to swap a battery on an F300 now and then. I am guilty of using an improperly sized screwdriver on the screw marked in the photo below (not my photo). Thankfully, I have avoided damaging the screw significantly so far, but would like to have the correct tool. What is the proper size of screw driver for this?
This one is for one of the ETA 7750 based Speedmaster date watches.
So you end up with half the screw head still attached to the threaded part of the screw, and half snaps off. You then have to use the half that is there to unscrew it and install a new screw.
Thank you, Archer. Very informative and helpful.
I have exactly this situation with one of my watches - half head is still attached. And I am a little nervous to try unscrew it, having already unsuccessful attempt with another watch, when second half snapped off as well, and I had to put that watch on a shelf until I find proper tool to remove it.
So any tips on how to address half broken head? Thank you!
Does the head of the screw stick up above its surroundings? If so, you could use a screw head file to cut a new slot at 90 degrees to the old one, to remove the screw. You might be able to do this even if the screw is flush with the surroundings, if there's enough room to get the corner of the file in there.
If not, then you just have to use the screwdriver up against what is left of the screw head, and turn it out.
In your experience, how standardized are screw head lengths, widths, and depths across brands, either in the vintage era(s) or the modern?
How about within brand, controlling for movement size (a ladies watch probably wouldn't have the same screws as a pocket watch)? Is it common to be able to swap screws from different movements from the same company from the same era?
How often do you redress your screwdrivers for your different purposes or maintenance?
This is #12 in my series of basic watchmaking tips.
Combining two shorter topics here, because of a need I see on the forum for one, and a request was made to me via PM for the other.
First fitting a new stem. Now this is just the way I do it – you don’t have to follow this, but it works for me.
Here is a new stem and crown that needs to be fitted to a watch:
New stems tend to be very long, so I like to get them cut down first to something close, to make it easier to fine tune the final length. With the movement fitted into the case, install the stem – fully install it so if it uses a screw to lock the stem in place, make sure it’s locked down:
Now mark the stem right at the end of the case tube:
I typically mount the stem in a pin vise through this process, but when you do so, make sure that the 4 jaws of the pin vise are clamping on the 4 flat surfaces of the stem, and not the round surfaces:
Clamping on the round surfaces can raise burrs, that then essentially become cutting tools that will chew up the soft brass in the main plate:
Now cut the stem at the mark you made:
You can use different things to cut the stem, but I just use side cutters. This will leave a rather jagged end, so if using this kind of tool you have to be aware that you need to cut it in such a way that you can clean up that jagged end, and not have the stem too short. It won’t be too short here of course, because you have left plenty of length.
For cleaning up the end of the stem, there are different tools you can use. If you cut it with a Dremel cut off wheel, it will be pretty clean already. But if you need to remove uneven material, you can just use a small file. I tend to use a stone – holding the stem end against the stone, I move it in a figure 8 pattern that you can see on the stone. Using this pattern keeps the stem end perpendicular to the threads:
I always put a very slight chamfer on the end of the stem that I just cut, before screwing the crown on:
Next I install the stem and crown:
The next thing you need to do, is determine how much stem you still need to cut off. So something to use as a gauge is helpful, and I often use a screwdriver blade:
I can then remove the crown, hold the blade to the stem, and determining exactly how many threads I need to remove from the stem. Then it is given the final trim, and fitted to the watch:
Now if you want to use Loctite, apply a small amount to the threads of the stem, and then screw the crown on - back the threads out, then screw it on again. Of course the stem itself should be properly lubricated, as well as the case tube and crown gasket.
Note that there is a very small gap between the case and the crown. This helps ensure that you don’t cut it too short if there is some play between the movement and the case. It also helps people grip the crown better when they need to move it to the time setting position. Not sue much an issue with a large crown like this, but it can be with small crowns on smaller dressy watches.
If you have any questions on this, please ask.
Next post will be on screwdrivers...
