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Tips for screwing in tiny screws


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Ok, so I just completed unassembling and reassembling the ETA 7001, and the tiny screws are really hard to handle. Unscrewing them during disassembly is ok, but screwing them in perpendicular to the screw holes during reassembly is a real pain. Some of them have a shorter shaft length compared to the flat acre head! Some of the times I try screwing them in they just go in at an angle which could damage the screw threads so I unscrew them and try again.

does anyone have any tips for screwing these tiny screws in straight?

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 First thing  I do is to dress the driver and no wider blade than screw slot.

Second is to magnetize the driver so it keeps the screw attached to the driver as I  put it prependicular on the blade.

Third I place the cock/mainplate on an anvil or hard surface, oil the jewels and end stones and drive the screw home. This will give you much control over the task and is less risky specially when removing the screw,  as opposed to trying this on a partially assembled movement mounted in movement holder. Demag.

 

 

 

 

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Practice will perfect your modus-operandi for getting the screws to their holes ready for screwing in.  Use well dressed tweezers if you use these to place the screw (you can get special screw holding tweezers, but they aren't always effective). 

I always turn the screw anticlockwise (normal threads), ie unloosening direction first with a light pressure until you hear/feel a light click, this means that the starts of the threads are lined up.  The screw then also tends to sit upright and will screw in easily with a light touch only needed.  This is standard engineering practice, especially when screwing a hard screw into softer material and avoids the screw starting a new thread.  A steady hand also helps !!!

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I've yet to find a watch screw, even in very cheap movements, that wasn't somewhat tapered at the end. Ditto with a screw hole that isn't beveled at least a little. If the hole is parallel to the ground, I drop the screw into its hole with tweezers. The taper/bevel combo is enough to get it to stay upright and oriented close enough to perpendicular that I can switch to a screwdriver, and as long as I don't knock it out trying to get the blade into the slot, it'll drive home easy peasy. The other part of the strategy is to turn the screw out initially until the first thread of the screw drops in past the first thread of the hole, [i]then[/i] you know the threads are mated, won't cross, and you can drive it home.

The only time I've had issues with this strategy has been outside of watchmaking with very cheap screws that are flat at the end, and coarsely threaded, and holes that aren't beveled. They tend to drop in at an angle dictated by the angle of the thread rather than anything you want.

Edited by spectre6000
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On a few worst case scenarios like horizontal placement where if screw falls, or is lost, retrieval will be difficult or disassembly will be needed to recover, and access space precludes tweezers or a pin vice, a minute glob of Silly Putty, pressed on to the screwdriver blade, will hold the screw securely enough to get it in place, and start the thread. 

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5 hours ago, LittleWatchShop said:

A sliding pin vise is useful for this.  Some are made especially for extremely small screws--I think for balance wheel screws.  I have a set with varying sizes that save my butt when installing the hairspring screw on a balance cock.

I usually use these when I polish the screwheads, think it is great when someone think out of the box and finds more use of them. -great stuff @LittleWatchShop

Edited by HSL
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Wow thanks for all the replies!

9 hours ago, Nucejoe said:

 First thing  I do is to dress the driver and no wider blade than screw slot.

Second is to magnetize the driver so it keeps the screw attached to the driver as I  put it prependicular on the blade.

Third I place the cock/mainplate on an anvil or hard surface, oil the jewels and end stones and drive the screw home. This will give you much control over the task and is less risky specially when removing the screw,  as opposed to trying this on a partially assembled movement mounted in movement holder. Demag.

 

 

 

 

How do you magnetize the screw driver?

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8 hours ago, LittleWatchShop said:

A sliding pin vise is useful for this.  Some are made especially for extremely small screws--I think for balance wheel screws.  I have a set with varying sizes that save my butt when installing the hairspring screw on a balance cock.

Surprisingly I faced a lot more trouble with the screws for the setting lever spring!

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Most important is the size and condition of the screwdriver.

On most watches I usually work with 2 screwdrivers, the 1mm and the 0.7 but I have a whole bunch of different sized ones for 'special cases'.

Example a big screw head (1.6mm) will usually require a similarly sized screwdriver, but the slot width varies from watch to watch...some have really thin slots (like the screw holding the automatic weight on a Seiko 6xxx) which require a broad, thin blade. using a narrow thin screwdriver will mess up the screw and/or the screwdriver tip.

Wrt to the condition, the tips must be flat in profile from both sides.. ie the wide part needs to be really flat and the edge needs to be flat as well. This will enable the blade to sit squarely in the slot and it wont try to ride up and out of the slot.

Dressing screwdrivers and tweezers is part of the routine and I do it at least once every two weeks (probably after working on 3-4 watches).

Personally, the most irritating screws for me are some of the dial feet screws where you have to hold the mainplate edgewise and try to start the screw.. I usually use rodico to hold the screw in place.

 

Anilv

 

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2 hours ago, ifibrin said:

Surprisingly I faced a lot more trouble with the screws for the setting lever spring!

Especially the ones on the underside of the plate, where you have to hold it in place with a finger and put the screw through and try to find the hole in the setting lever. But after while it's not that bad.

The hairspring stud screw gets my vote. The other one that irks me are those tiny jewel plate screws. And all the screws in ladies watches.

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On a related topic...not so much with small screws...

When I pick up a screw...a plate screw or something...it is invariably oriented incorrectly in my tweezer.  Just the other day, I discovered the idea of dropping the screw into an available LARGE hole so that its head is neatly exposed and easily captured so that the screw is orthogonal to the plate--just how I want it to place into its proper hole!!

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7 hours ago, OneBadWolf said:

On a few worst case scenarios like horizontal placement where if screw falls, or is lost, retrieval will be difficult or disassembly will be needed to recover, and access space precludes tweezers or a pin vice, a minute glob of Silly Putty, pressed on to the screwdriver blade, will hold the screw securely enough to get it in place, and start the thread. 

Or even Rodico. And you can just pick it off once the screw is started a little.

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Yes, I too hate the h/spring stud screw. So easy to slip and wreck the hairspring, especially ladies watches!!    In the past with the screw in-situ I have stripped a small piece of insulation off a suitably sized small electric wire, just a mm or 2, and slipped it on to the screw or screwdriver.  This stops the screwdriver form slipping off, but means you have to rely on feel for it going into the screw slot. Can sometimes work to fit the screw as the insulation has enough friction to allow the screw to start. Otherwise I find a well dressed screwdriver just a bit wider than the the screw also helps !!

Edited by canthus
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