Wednesday, 29 February 2012

Molnija 3602 Trench Watch Assembly

This is the assembly of a Molnija 3602 movement for a trench watch. I've edited this video to remove all my mistakes so you're not left watching me pick up the same screw 2 or 3 times... as a result you will see some screws magically appear in place or the movement suddenly flipped over. Hopefully you can follow whats happening. Similarly to the Seiko 6309 assembly that I've also got posted, this was completed for the most part without the use of any magnification, due to the crowding nature of my lamp and camera.


Wednesday, 22 February 2012

ETA 2824 Clone

This is a Chinese made ETA 2824-2 clone, fresh from Ebay. I've owned a real 2824-2 movement for 6-12 months and have all the technical documents on its assembly, but I still wanted my first crack at the 2824-2 to be on a clone instead of the real deal. If I do (did) happen to ruin this movement, then.. well.. it's only a Chinese knock-off, so no real harm done. The movement came in a two-part plastic case, with really flimsy hour & minute hands, a long stem & plastic crown(?).


I was surprised to see how nice the finish is on the top plates, with very nice patterns on the bridges and stripes on the rotor.


Here's a close-up of the movement sans rotor.


 And now with the automatic winding bridge removed.


A close-up of the separated winding bridge.

 

I'm quite happy with the overall finish of this clone - I've owned some good quality Chinese movements like this one, and I've also seen some tragic pieces of crap that are so poorly finished you almost lose the will to reassemble them..

 

Now with the train bridge removed, the wheels are exposed. I don't have a photo of the bare reverse side of the plate, but interestingly, the 2824-2 does not have a center wheel and cannon pinion which would be comparable to most other watches that I've covered in this blog.


The obverse of the movement is not as nicely finished as the reverse, but then again, you can't see this side when the movement is installed in a watch.


 Almost ready for cleaning...
 

Ceaned, oiled & reassembled - the original article versus the clone.. now I've got to find something to do with it... possibly a custom diver..?

 

Seiko 6309 Assembly Videos

This is my first attempt at filming an assembly, which was surprisingly difficult. I've got a 10mp 'tough' camera on a macro setting, held in place by a frame made from a coat hanger... Combined with a very close light source, there was no room for my head and my loupe... so I've had to assemble this movement from afar (5-6 inches) with no magnification (I also edited out the major mistakes & the sound).



Monday, 20 February 2012

An idiot's guide to mainspring disassembly and reassembly

When a watch mainspring is wound, it contains a large amount of energy. Even when the spring is in its most relaxed state within the mainspring barrel, it still contains a lot of energy. When removed from the mainspring barrel incorrectly the spring will fly out and hit you in the eye. For this reason, only the correct tools should be used for removing and inserting the spring into the barrel. Having said that, in this post I will remove and install a pocket watch mainspring by hand using the incorrect tools. This should be the last time I have to handle mainsprings like this as I have a nice winding set coming in the mail...

To start, the mainspring barrel, the picture on the left is the underside (front of watch), the right is the topside (rear of watch).


Take a flat tool and pry the lid off the barrel, whilst applying light pressure to the outside of the barrel, so that the central arbor assists in raising the lid.

 

Watch that the lid does not fly off! Get the flat tool into the barrel and hold the spring down. Always keep pressure on the spring until you are sure that the arbor won't pull it out when removed.

 
 

Surround the barrel with as many fingers as possible, and slowly draw out the spring so that the spring slowly unwinds into your fingers.

 

Success! This spring is due to be retired, as the central notch that attaches to the arbor is fatigued and will likely break or fall off when wound slightly. However, I'll put it back inside the barrel anyway.


Start by lining up the outer notch of the spring with the notch in the barrel. Keep pressure on the spring to the lip of the barrel, whilst turning the barrel.

 
 

Success again! The old spring is reinstalled in the barrel. The downsides to this method are the incredible ease with which you can break/bend/generally mess up the spring (especially with smaller watch reverse coil springs and barrels), the ease with which arbors and barrels can be flung across a room and lost forever, and the grubby finger prints, oils and dirt that can be transported into the mainspring barrel (I should use finger gloves).

Sunday, 19 February 2012

How to disassemble a mechanical watch - Elgin 7 Jewels from 1913

This is a fantastic 1913 Elgin movement that has 7 jewels, bimetallic balance and blued Breguet over coil. Before disassembly of any mechanical movement, it is critical to let down the mainspring. This simply involves relaxing the spring inside the mainspring barrel.
 

 To let down the mainspring the movement will be required to stay in the case (pocket watch movements) or will require the stem to remain attached (wrist watch movements generally don't have to remain in the case to use the stem). When the stem is advanced slightly, the click (the ratchet that prevents the mainspring from unwinding) will creep along the largest gear on the top of the movement, which is connected to the mainspring barrel. It is when the click is advancing that a small pin or tool can be used to disengage it from the mainspring - be very careful to hold onto the stem tightly and release energy carefully. If you lose your grip on the stem and have the click held open, then the mainspring will make a 'snapping' sound as it unwinds in an instant - this can damage any number of parts in the watch, such as the going train (gear teeth, pivots, jewels) and very likely the mainspring itself.


Once the mainspring is let down the dial will need to be removed. Typically this is achieved through the releasing the dial foot screws located on the side of the movement. In older pocket watches such as this Elgin, you may find three screws to release. On most wrist watch movements, there will typically be two screws holding the dial to the movement. On this Elgin, the dial screws are at the 4, 7 and 11 o'clock positions.


The dial can then be removed to expose the obverse of the movement.



Now the real disassembly can start: I begin by removing the balance assembly, which is held in place by one screw and two steady pins.


The balance can then be examined, check to see if the jewel, spring, pivots, poise, trueness, etc. are all good.

The next step is to removed the bridge holding the gear train, held in place by two screws:

 
 
 

Before the mainpring barrel bridge can be removed, the winding gear on the top of the mainspring must be removed, along with the transmission gear:


The two screws holding the bridge to the plate can be removed, and the bridge can then be lifted:



With all the main bridges removed the movement should look like this:


Time to get that mainspring barrel out of there:

 

And then the careful removal of the wheels, don't hold the wheel by the teeth/pivots:

 
 

Now the cock holding the pallet fork can be removed, along with the pallet fork:

 

I've left the keyless works to the end of the disassembly. There are actually four small individual components which make up the clutch pillar - being removed in the following two photos:

 

I actually don't know what this part being removed is called, it assists with the selection of the winding/setting for the clutch pillar. The arm at the base of the clutch pillar also needs to be removed (no photo for this), it is simply held in place by a screw.


Now the movement is flipped over and the hour wheel can be removed:


The bridge holding the minute wheel can be removed. The two screws holding the bridge are quite small, so care should be taken when holding with tweezers - if you apply too much pressure and the screw pops out of the tweezers, you'll have almost no chance of ever finding the screw again....


The cannon pinion can be removed, another tool is required to lift it off the centre wheel, but I didn't get a photo of that.. so here's me holding it above the centre wheel..


The bare main plate stripped down apart from the balance jewels, and the pins for the pallet lever:


The (mostly) disassembled movement ready for cleaning: