Lorsa 238G Service

[jdm]

This is well made mov’t that wasn't running. No surprise, as both balance pivots were snapped, there is no shock-protection on this version.

 

I'd classify this mov’t not the best for an absolute beginner, it's 11.5’’' size is fine but there are three flat wire springs not very friendly,  many small screws all of different sizes, so to require a full set of screwdrivers. It is interesting to observe how many construction details that have evolved from this old design for reasons of optimization, cost and part count reduction.

Let’s get started. To release the stem undo completely  the setting lever screw,, then either pull it out, or be careful as it likely will drop as you turn the mov’t over.

 

Dial screws are on the sides and best handled with a 0.70mm driver. Especially if you’re using an ultrasonic cleaner it’s a good practice to remove them to reduce the risk of dropping during work.

 

Remove the dial washer and hour wheel, since the date ring spring holds on the other side of calendar plate I suggest that for caution you place the mov’t in a plastic bag after removing the three screws, and before lifting the plate.

 

The day spring is tucked under the calendar plate, which I have turned up to show in the below picture

 

You can put away the bag for now to remove the date ring, wheel,  and finger, as well as the cannon pinion and the setting lever screw.

 

Now lift the setting spring to reveal the joke and its spring, be cautious when removing the latter.

Remove the joke, setting wheel and pinion, clutch wheel, sliding pinion, setting lever, as well the balance cap jewel, and we're done with this side of the mov’t. Strangely, the escape wheel cap jewel was missing.

 

In reality the picture above has the setting lever still in place since I had not removed its screw yet. Now for the other side.

 

Since I had removed the balance cock already, it’s now time to let down the mainspring with the usual pegwood braking technique. We can now remove pallet cock screw, pallet cock, pallet fork, escape wheel cap jewel, And crown wheel  (left-handed). Also remove the crown wheel spacer pictured below.

Remove the winding wheel screw and wheel, then be careful in removing the click spring, time to use the bag again perhaps. Finally remove the click screw and click. Having taken apart the complete winding system we can now remove the two train bridge screws and the bridge.

Train is of the classic type, three wheels plus the escape one, which can now be removed. And finally two more screws for the barrel bridge, the bridge and the barrel.

About the barrel and mainspring (sorry,  not pictured) I opened the lid and found everything clean and in order. Since I was not to replace the mainspring I took no further action on moved to general cleaning. I did a couple washes in petroleum ether (refined naphtha) and isopropyl alcohol but some opacity remained on the plates, so I left these in ammonia-based cleaner for few hours, then rinsed in petroleum ether. Note that the latter (unlike lighter or engine fuel) contains no oils, fragrance or other additives, and leaves no residue at all.

 

Much better, barrel and bridge already in place!

 

About reassembly, I will not detail all the steps, but only highlights some important aspects.
For lubrication I’ve only used three modern, fully synthetic products by Moebius:

• HP1300 for high-torque parts like winding and setting.
• 9010 fine oil for other pivots and jewels, it’s easy to apply from the outer side of the hole jewel.
• 9415 for pallet stones, only because I’ve just received it.

Below from left to right, escape wheel cap screw, lower balance cap screw, balance upper cap screws, All have different sizes, so unless you photographed or otherwise set these apart you’ll have to use some logic to refit correctly. Same goes for all the other screws… they may look the same.. but they are not!

 

Below the balance upper cap jewel. It also holds in place the regulator arm, for this purpose it’s slightly beveled.

 

You will have to fit the setting lever on the dial side, and its screw from the other. Just use some rodico to keep the lever in place.

 

The setting pinion goes with the bevel toward the sliding pinion.

 

Ratchet and crown wheel screws have different head dia. length and thread direction.

 

 

You may want to use the plastic bag to fit the click spring safely. Fit the click first, then the long leg of the spring under it, then the bent leg to sit firmly.

 

The yoke and setting lever springs are also a bit tricky. All these pivots and sliding points are lubricated with HP1300, don't forget to test the working repeatedly before moving forward.

I've found the date ring spring to be the most difficult, because it’s underneath the calendar plate as shown in the disassembly picture. After the spring is in the plate either fit it with a siding manoeuvre to place the spring against the date finger, or position the plate with the screws kept loose, then push the spring in place by the cut that is on the plate for the purpose.

There is no date quick setting on this basic mov’t, that is done setting time back and forth across midnight. The finger on the date wheel is pivoting when moving backwards with the help of a really small spring. However doing that much setting counter-clockwise every other month does not damage the escapement, as sometimes is  feared.

 

The replacement balance complete came in the “a vis” version, which are there for poising, not rate adjusting. Actually I think the stubs are pressed not screwed.

 

One last detail for the correct installation of the dial washer. Flat side faces and slides on the hour wheel, you can use HP1300 there. The edges somehow grab on the bottom of the dial.

 

 

This veteran Swiss could have rewarded me a bit more on the instrument, but I hold no grudge to it and won’t try stunts as fixing beat error at the hairspring collet, adjusting for positions, or getting the missing cap jewel.

 

And that is why I won’t, it would not make much sense for a desk clock! 

 

Now, who should own something like that? My friendly blacksmith, of course!

 

I hope you have enjoyed  my  “no pretenses” article!