Mk II Speedy Project

I guess I was just lucky with the Arsa and then the GP Mk II, that they did not suffer from creep. I am glad that I have encountered these problems because they are testing my diagnostic and problem solving skills and are being stored in the memory for future use - without being pushed, we learn nothing other than robotic procedures.

The Omega method seems stupid to me because if there is a problem, you have to un-case the movement and remove the hands and dial, then replace them etc. Al's way was just instinctive to me, as I'm sure it would be to any engineer.

Of course, I could say that I used the official Omega method with the Soccer Timer 😗

..... but I didn't. I just cocked up.

With creep:


Without creep

Back to the project:

Nearly there:

The hands have been re-set.

As phase one (the "easy" bit) is now over, all that remains is to offer a big "Thank you" to Al for his advice and open criticism. This has definitely stopped me cutting corners I, otherwise, would have.

Phase two is to try to restore the edges, by hand, to the case which is horribly rounded.

There is one, last, question I have and that is regarding the crystal. On the GP Mk II, it had the original crystal with the plastic, crystal gasket, but the "new" crystal I got, with this watch, takes an O ring gasket, set into a groove in the centre of the crystal. Without the O ring, the crystal will drop straight in but the O ring adds quite a lot to the diameter of the assembly, compared to the old plastic gasket.

I have read horror stories of people trying to fit this revised crystal so, Al, are there any tricks to fitting the crystal - lubricate the gasket with washing up liquid or something else?

Again, thanks.

Stewart

Once again, thanks Al. I have no problem with constructive criticism even when it is open to however many billions of people on the internet.

The engineer in me says to reverse the process and press the case onto the crystal, so I'll try that first. If all else fails, It sounds like I might have to buy a new crystal from STS and get them to fit it. It just pains me (and I'm sure it does you, too) than something this mundane can't be done without outside help.

I would say there is 0% chance of you pushing it in, the edge of the case is sharp and not chamfered like some, it will tear up the o-ring for sure

I have one of those tools for the MKII crystal, an ebay find a few months back 👍 Havent used it yet though.

Before I had this tool I made a plastic sleeve which achieves the same thing. Its a cone shape made from hard plastic from a large plastic bottle. Its small end is just the same size as the crystal and as you push down on the crystal it compresses the o-ring and then both can be pushed into the case without damaging the o-ring. A bit fiddly but works ok and works in the same fashion to the genuine one except that it has a small lip on the inside to hold the o-ring in place just before you push it into the case - I think this just makes sure that the crystal is totally flat before it enters the case

Also I found that if I didnt get the crystal 100% aligned when I installed it, I could turn the crystal the 1/2mm it needed using one of those rubber case openers to push down on the crystal and turn it, it is a very tight fit

edit: A picture of the tool if you're interested how it looks ............my alternative on the right, the base is totally flat and smooth, i just didnt bother too much with the top edge 😜

Thanks. I'll rummage around tomorrow to see what I can use to make one.

A morning of tool making…

Refusing to be beaten and with thanks to pascs for his picture and inspiration, I spent a good hour rummaging around for suitable materials, armed only with imagination and a Vernier caliper. Dismissing various plastic containers as too wide, too narrow, not thick enough etc. I stumbled on an old, half litre, household plant sprayer – the type with a bulbous bottom and a long, slowly tapering neck (no, not J. Lo.) hidden at the back of the cupboard under the sink. Perfect.

This is what’s left of it but I’m sure you know the type I mean.




Knowing that the diameter of the crystal is 36.5mm and that the base of the tool has to be perfectly flat, I needed some kind of former to make the get it level. So, having hacksawed the neck off at an appropriate length (leaving enough to be able to hold the work) I found the perfect former in the shape of a 25mm socket with an o.d. of 33.71mm. Going this small meant I would have more finishing to do but also meant that there was more room for error as I only had one sprayer. Jamming the socket inside the sprayer neck, I used a Stanley knife to trim the plastic down (in stages) until the bottom surface was perfectly aligned with the face of the socket – remembering to keep checking that the socket was centred inside.

Now I needed a perfectly flat working surface so that I could grind the plastic down to the right level and this turned out to be the ceramic hob in my kitchen. Starting with 40 grit aluminium oxide paper I took the length of the work down a little at a time, regularly checking the i.d. with both the caliper and the crystal. I moved onto 80 grit as the bulk of the material was removed and finished with 120 grit wet & dry. The crystal is now a perfect fit and the caliper shows 36.50mm. I then trimmed the top of the tool (as I then considered it) to give a height of 10mm. As pascs rightly observes, the top doesn’t need to be perfect so the fact that it varies in height between 9.8mm and 10.3mm doesn’t matter. I did sand the top down though, just to improve appearances.



Now for the moment of truth, a trial fitting of the crystal. Into the tool with the gasket on and pressed down onto a flat surface – perfect. Offer it up to the watch case (that I still have to work on) – that’s awkward because you no longer have a centring reference because the Tachy ring is a thin, printed film on the back of the crystal. Apply pressure and…

…cracking sounds. 🤬 This tool needs re-thinking. As the Tachy ring is at the point of contact, there is no hiding this so it means a new crystal. At least that one came with the watch but it does mean that I have something to experiment with.

The problem arises from alignment so I need to come up with a way of overcoming this “blindness”. The crystal is 3mm thick and the 0.8mm groove for the gasket is 1.6mm from the top and 0.6mm from the bottom so it occurred to me that I need a way of getting the bottom of the crystal to sit up to 0.6mm (no more) below the bottom of the tool.

More hunting around, this time armed with a micrometre, looking for something solid, flat and less than 0.6mm thick. Then I stumbled across a hard plastic luggage tag that I picked up at the London Ski Show a few years ago. The clear side was 0.5mm thick – thank you Ski New Hampshire. Drawing around both the inside and outside edges of the tool, all I needed to do was to cut out between the two lines and the crystal will pass through but the tool will not. The hole doesn’t need to be perfectly round, it just has to be inside of the outer line. Try with the damaged crystal, separate the two parts and it works nicely. There is a nice 0.5mm of crystal poking out from the bottom of the tool. So I offer it up to the case and the protruding crystal locates into the hole perfectly. Apply pressure and…

…the crystal slides in. Knock it out, try it again and…

…job’s a good ‘un.



OK, it has cost me £38 for a new crystal but it is very satisfying to have realised the problem, thought of the solution and manufactured the tool.

I have put this down in such detail, partly because of the honest and open way this thread about my project has evolved – warts and all – but also so that anybody wanting to make their own tool can do so without having to worry about the problems I encountered.


In use, I would suggest loading the crystal into the tool so that it is flat at the bottom and then placing it over the spacing plate and pressing again to achieve the protrusion. Of course I can’t guarantee that you won’t break your crystal if you copy my idea but it will certainly help you avoid doing so.

Stewart, thats definitely more professional looking than mine 👍

The 0.5mm flat plate is just used to get the crystal to stick out by a uniform 0.5mm, then you remove it and place the crystal up to the case and push it in?

The metal original one I have, has an inner lip into which the o-ring goes when the crystal is at the bottom. I'm thinking that when the o-ring is in this groove, than 0.5mm of crystal sticks out of the bottom of the tool allowing the crystal to line up into the case - I've not used the metal tool yet so I'm just guessing this based on your experiences.

Mine only looks better because of the material I was forced to use.

Yes. The only use for the plate is to get the uniform protrusion, then it is removed.

It would be interesting (to me, any way) to see your proper tool from the back. From how you describe it, I would think you are right

Not so easy to take a picture but hope this helps

Impressive work .

Great thread! Thanks to all contributors. This may come out handy at some point.

Tremendous post thank you. Appreciate the explanations and pictures.

I've read this thread a couple of times. It is still my Favourite Omega Forums Thread, to date. Grateful thanks to all that contributed..