Seiko 7A38 - by the numbers

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Forum Home > Bend it, Mend it - Mods & Wreckers > My First Formative Franken Fred Force 10 Fumblings ....

Seiko7A38
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Posts: 9333

If you've read the FRED thread ....

Then you'll know that two weeks ago, after hours of research, I finally discovered what the original Fred Force 10 '7A38' looked like.

Early in July, in that same thread I'd written that I wasn't going to do anything with my NOS Fred dial(s) until I knew. Well now I do. :)


I'm sticking with my original concept, in that I plan to build it into a modified two-tone 7A38-7020 watch case, not too dissimilar from another Franken I'd built a couple of years back. My quandry had been that I also wanted to use the Fred Tachymetre ring with the Fred dial, but I'd more or less dismissed it on the grounds that it wouldn't fit. Except yours truly had just assumed that it wouldn't. :roll:


Here's a Fred painted brass Tachymetre ring (the grubbiest of the three) next to a Seiko p/n 84311029 plastic Tachymeter ring ....

which if 'push comes to shove', I may have to end up using. This will require the locating lugs and 'pips' shaving off the underneath.




When measured, the Fred Tachymetre ring is 31.20mm diameter - the Seiko p/n 84311029 is just slightly smaller at 31.00mm dead !

So I had just to try it, to see if it would actually fit in the 7A38-7020 case, didn't I ? 


September 21, 2014 at 4:06 PM Flag Quote & Reply

Seiko7A38
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Posts: 9333

Amazingly, although a bit tight, it actually fitted ! :D




Problem is that when you flip it over, those six cut-outs around the perimeter are all too visible. :(




I was toying with the idea of filling them with small pieces of white plasticard, but ....


September 21, 2014 at 4:31 PM Flag Quote & Reply

Seiko7A38
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Posts: 9333

Then I offered one of the Fred Force 10 dials up from underneath ....




So not only have I got six annoying little gaps around the perimeter of the Tachymetre ring, but a gap between that and the dial ! :mad:


The reason for the gap is just visible inside the case, through one of the dial cut-outs:




The small machined flange inside the watch case ! The Fred dial is one side of it and the brass Tachymetre ring on the other ....

and the way things stand at present, never the twain shall meet. So It looks like I'll be using the plastic Seiko Tachymeter ring. :/


Of more anon ....


September 21, 2014 at 4:37 PM Flag Quote & Reply

Seiko7A38
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Posts: 9333

Before I go any further, please accept my apologies for the variable quality of the photos in the following posts .... 

Most were artificially lit; some taken by flash  when my main priority was getting on with the job, rather than recording it. :P


Earlier in the week, I'd mounted one of the Fred Force 10 dials on a gash (but working) Seiko 7A38 movement.

The dial is the worst of the three I have, in that apart from being slightly grubby, it has some paint loss due to mis-handling / storage.




Look near the '20' of the 30 minute counting subdial and the outer dial ring motif near 48 minutes and you'll see a couple of breaks in their black outlines. I suspect this damage was probably inflicted by the locating dowel of a Tachymeter ring, stored loose with it. :/


September 28, 2014 at 3:34 PM Flag Quote & Reply

Seiko7A38
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Posts: 9333

Of course, when I offered said Fred Force 10 dial with 7A38 movement up to the 7A38-7020 watch case, I had the same problem ....




That wasn't the half of it, though. Because when I flipped it over, not only was the movement protruding from the case slightly:



But, without even attempting to insert a crown stem, I had a major pusher shaft / switch actuator lever mis-alignment problem:




I really should have known what to expect, because I've been here before, four years ago, got the T-shirt and failed (in public) ! 


The mis-alignment problem is caused by the differences in dial construction and (double plate) thickness of the Fred Force 10 dial. 




Or should I say a combination of different thicknesses and how they mate (or not) with the chosen watch case's dial mounting flange:


September 28, 2014 at 3:47 PM Flag Quote & Reply

Seiko7A38
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Posts: 9333

The way I got around the dial construction / thickness / chosen watch case problem 4 years ago was simply to abandon that project.

Well, not exactly.  Instead of fitting the 7A38-6109 609L sample case dial into a two-tone 7A38-7289 as I'd originally planned ....

I ended up building two Frankens - this one, which I posted in the WRUW thread recently and my 7A34 / 7A38 Franken


Now I will admit that earlier in the week, I'd started looking at other 'more suitable' watch case options. 

Indeed, bearing in mind that the Fred Force 10 dial is of the typical C.G.H. dial blank layout / construction ....




I've sussed that it would fit perfectly well (without any modification) and look the part in a dressy gold tone Yema N81W53 like this.

However, even though I have two of these (different versions, one with the gold baton dial, the other with the Roman Numeral dial),

both are pretty near mint and far too nice in their own right, to consider converting into any kind of Franken. 


September 28, 2014 at 4:45 PM Flag Quote & Reply

Seiko7A38
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Posts: 9333

Nope. I decided I was going to stick with my original plan - and make it work this time. The solution was actually quite simple. 


I needed to reduce the diameter of the Fred dial from 31.20mm to approximately 30.6mm, so it would fit inside the mounting flange.

So after scribing a line around the edge, using the inner diameter of the case flange as a template, that's exactly what I did. 



September 28, 2014 at 5:13 PM Flag Quote & Reply

Seiko7A38
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Posts: 9333

All I've done, by very carefully filing and sanding (by hand), was to take off a little over half a millimeter all the way around the dial.

That's just enough to allow the Fred dial to protrude through the 7A38-7020 case's dial mounting flange and instead sit flush with it:




Positive location is now provided by the movement spacer butting up against the underside of the watch case's (dial) mounting flange.

Flip it over and the previous pusher shaft / switch actuator lever mis-alignment problem is resolved:




With the bezel and Fred Tachymetre ring dropped in place - no more unsightly gap (at least not between the dial and ring, anyway).





Note the crown / stem now fitted to check correct alignment with the movement.


September 28, 2014 at 5:41 PM Flag Quote & Reply

Seiko7A38
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Seiko7A38 at September 21, 2014 at 4:31 PM

Problem is that when you flip it over, those six cut-outs around the perimeter are all too visible. :(




I was toying with the idea of filling them with small pieces of white plasticard, but ....


That other annoying little cosmetic issue (in using the Fred Tachymetre ring, as opposed to a Seiko one) still exists, for the time being.

But I think I may have found an alternative solution in this thread:D


September 28, 2014 at 5:58 PM Flag Quote & Reply

Seiko7A38
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Posts: 9333

It lives.  Or at least this first iteration of the Fred Force 10 Franken does - for the time being, at least.

This morning I fitted a few hands to the prototype gash dial / movement. For want of anything better ....

I've used the hour, minute and sweep second hands from the original two-tone 7A38-7020 donor:




I'd studied that 1989 French magazine image of the original Fred Force 10 '7A38' and almost convinced myself that these three hands were stock 'parts bin' Seiko items. The sweep hand at least certainly looks very similar. However, they're not the same as these which I've used. For one thing these minute and sweep hands are slightly longer. As you can see from the above, the tip of the minute hand just slightly overlaps the outer outline of the dial motif - whereas on the original Fred Force 10, the tip is in the middle of it. Similarly, the lume pip on this Seiko sweep hand is closer to the two gold pips at '12'. But those aren't my biggest concern at this moment.


You'll notice that the two chrono' sub-dials are currently without hands - just one fitted to the constant seconds sub-dial. I'm not sure, at this stage what the Fred '7A38' actually uses for sub-dial hands. In that old magazine image they appear to be all black and have standard size bosses but disproportionately spindly pointers. Almost reminiscent of the sub-dial hands used on the YSL Yema N7.


I don't like them, personally, and seeing as this is a Franken-watch anyway, I decided to do my own thing - gold bosses (to match the dial pips) and black pointers. So naturally you might have expected I would have used the three p/n 04E14AL hands off the two-tone 7A38-7020. Can't - they're too long. The Fred sub-dials are smaller diameter than most 7A38's. So the one shorter hand I've got fitted at the moment is a p/n 03E12XG off a 7A38-6109 sample case dial. The 7A38-6109's constant seconds sub-dial is smaller in diameter than the other two (which incidentally also use p/n 04E14AL hands). The only other 7Axx which uses these particular shorter sub-dial hands is the two-tone 7A38-6080. Cousins don't list them but Seiko Australia show them as in stock.


I may yet re-think the hands altogether and 'bling it up' a bit - and go for an entirely different all gold-plated handset. Let's see. 


September 29, 2014 at 9:22 AM Flag Quote & Reply

Seiko7A38
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Now where was I ? :/ Ah Yes - couple of minutes later it was back in the watch case - again for the time being, at least. ;)




However, getting the dial / movement out and back in again wasn't quite as simple as 'plopping it out' into your hand. Oh No. 

In my quest for a 'precision fit' the tolerances are all just a bit too tight at the moment. Remember this line from a previous post ?

I needed to reduce the diameter of the Fred dial from 31.20mm to approximately 30.6mm, so it would fit inside the mounting flange.


Well that's fine and dandy when you're gingerly squeezing it back in without the bezel and Fred Tachymetre ring fitted to the case.

Don't forget that unlike the Seiko plastic Tachymeter ring, which 'floats' between the case and bezel, the Fred ring is murder tight.

That's why (as you may have noticed in my previous photo) I'd already reamed out the hole in edge of dial (adjacent to 46 minutes) which accepts the Tachymetre ring's locating dowel, from 0.7mm to a more generous 0.9mm - to allow a degree or two of leeway. ;)


So the next Fred that dial I reduce in diameter, I'm going to trim it down to 30.5mm. Nobody's ever going see the 'gap' but me. :P


September 29, 2014 at 11:49 AM Flag Quote & Reply

Seiko7A38
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Posts: 9333

Couple of quick updates:

I've ordered a Seiko p/n 310P03HB0A crystal from Cousins UK, hoping that its gold ring will help hide the slots in the Tachymetre ring.

Also ordered three more p/n 03E12XG sub-dial hands from Seiko Oz (via the ever-obliging Keith Doherty of Smith & Smith in Sydney).


Started toying with a couple of different ideas for bracelets and decided that the Seiko p/n Z1005C which I previously had fitted on my 'split dial' 7A38-702X Franken works rather better on this (though there's still the same discrepancy in bracelet / case lug end widths).




The case-back on the donor watch was quite badly gouged with the usual ham-fisted slipped tool marks - so I've 'sterilized' it. 

Flatted it off with Wet and Dry paper, starting with 400 and finishing with 2000 grade and gave it a light polish. It fairly gleams now. 8)


October 1, 2014 at 11:42 AM Flag Quote & Reply

Seiko7A38
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Seiko7A38 at September 29, 2014 at 11:49 AM

So the next Fred that dial I reduce in diameter, I'm going to trim it down to 30.5mm. Nobody's ever going see the 'gap' but me. :P


On Sunday, I spent a couple of hours doing just that. VERY carefully filing and sanding away at the best of the three Fred dials.

I'm not entirely happy with the result, but  those couple of extra thou' certainly make it easier to pop the dial / movement in and out.

Here's the second 'reduced diameter' Fred dial dummied up on another gash movement in another spare 7A38-702X watch case:




.... and with a Fred Tachymetre ring dropped in place to check alignment and for any unwanted gaps:


October 6, 2014 at 8:25 AM Flag Quote & Reply

Seiko7A38
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Posts: 9333

Speaking of 'gaps' ....


Here's a Seiko p/n 310P03HB0A crystal (as normally used in a 7T62-0FD0) dropped on top of a Fred Tachymetre ring.

The crystal measures 31.0mm diameter and the ring 31.2mm. So it was tricky to align them perfectly concentric by hand.



However, even like this it was pretty apparent that the crystal's decorative gold ring wasn't going to be quite big enough to hide the six cut-outs around the perimeter of the Fred Tachymeter ring. Confirmed when I tried fitting it to the watch case / bezel this morning:




How much you can see of them depends what angle you look at the watch, but in this Q&D shot the gap at '12' (above 60 on the Tachymetre) is the most obvious. There's another between 400 and 350, just to right of where the camera flash caught the bezel.


October 6, 2014 at 8:41 AM Flag Quote & Reply

donwatch
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Posts: 520

It is a one of a kind  :/   the cut outs go with the inner hour markers  Looks good, Paul  :D

October 7, 2014 at 1:04 AM Flag Quote & Reply

Seiko7A38
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Posts: 9333

As indeed are all the best Frankens, Don. :P

Except Franken Fred is not looking so good today. He's been back on the operating table again. Two steps backward this time. :(


It stems from the machining tolerances of the Fred painted brass Tachymetre ring. On the basis that it was likely to get even grubbier while I was trial fitting the cut-down dial(s) I'd been working with the grubbiest of the three rings. All three may measure precisely 31.20mm in diameter, but the exact positioning of their dial locating dowels and depth of 6 cut-outs appears rather more variable. :/


Result being that after I'd changed the 7A38-7020 case's original black nylon crystal gasket for a new clear one (Seiko p/n 86179152), then dropped in the cleanest of the three Tachymetre rings, I had much bigger gaps showing on one side - and nothing on the other.

More annoying is that after pressing that crystal in so carefully, I've got a bit of something (skin flake or dust) trapped under it. :mad:


That said, it's still looking promising. :) Especially if  the sunlight catches it right - that is if you can actually find the sun today. :roll:

Excuse the Q&D hand-held shot:


October 7, 2014 at 7:39 AM Flag Quote & Reply

Ross McS
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Posts: 24

It looks great - and a million times better than the watch that the dial was intended for!!

October 7, 2014 at 3:29 PM Flag Quote & Reply

Seiko7A38
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Posts: 9333

Cheers, Ross. ;)

Here's a possibly slightly better Q&D wrist shot of the first fumbled Franken Fred prototype, I rattled off in the early morning sunlight.



October 10, 2014 at 5:13 AM Flag Quote & Reply

Seiko7A38
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Posts: 9333

It's by no means finished yet - even in this first incarnation. But I should explain - I've been working to a self-imposed deadline. 


When I started this topic a little over two weeks ago, I had a silly idea. :P I haven't posted this particular photo in the thread before ....




Had I been building the Fred dial into a Yema / C.G.H. case (as indeed I may well do with the next prototype), I would have utilised a Shimauchi V906 branded movement naturellement - with a French / English day wheel - presumably as per the original Fred Force 10.

As it happened, the two-tone 7A38-7020 which in effect became the donor watch for the project had a German / English day wheel.

The German abbreviation for Friday / Freitag being FRE(d) and Friday the 10th only comes round a couple of times in any year. :D


Yesterday, I fitted the second, better condition (now reduced diameter) Fred dial, in an effort to get the watch finished by my deadline.

The Seiko p/n 03E12XG sub-dial hands I'd ordered via Smith & Smith still hadn't arrived. But I'd put a contigency plan of sorts in place. I'd sussed out a possible alternative - p/n 03E30HG, (the constant seconds sub hand used a two-tone 7T32-6A50, etc.) and ordered those from Cousins last week. I'm not sure what the 7T32 hand hole size is, but they really didn't want to fit on the 7A38 hand spigots.

With a bit of careful reaming and gentle persuasion eventually they did - after a fashion ! 


Readers who are familiar with my personal modding preferences may be wondering why I elected to use a Seiko clear nylon crystal gasket, instead of a Sternkreuz white nylon one, which I sometimes use with white dials / rings. It wasn't through choice. Last week, when I ordered the Seiko p/n 310P03HB0A crystal from Cousins, I'd also ordered a Sternkreuz p/n IG318310H intended to fit it with.

They supplied the wrong part. :mad: What I actually received was a p/n IG318311 (without suffix), which is only 0.8mm high - not 1.2mm.

So now I've got to go through Cousins' b*llsh*t returns procedure once again, to prove their mistake and get a correct replacement. :roll:


Those couple of issues, which will be rectified in due course, apart ....

I've still got a slight problem with the alignment of this Fred dial and Tachymetre ring, which is approx. one degree out (clockwise).

Obviously I've still got the issue with the six cut-outs visible around the Fred Tachymeter ring. I may yet try the Seiko one in there.

The 7A38-7020 donor watch case is still 'as was' and needs re-finishing, to the same standard as I've already done the bezel.

I may also try fitting a set of gold plated hour and minute hands and another different bracelet in place of the Seiko p/n Z1005C ....


October 10, 2014 at 5:15 AM Flag Quote & Reply

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