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Moose

National Watch Cleaning Machine. Restoration and repair.

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Next up is the motor speed control.

I did think long and hard about my original aim of maintaining as much originality as possible. And, there is no doubt that the original speed control rheostat was a) original and b) functional. But - as I was an electronics technician in an earlier life, and also health and safety professional in a more recent life, the safety aspects weighed heavily upon my concience.

Logic played it's part as well - with the original rheostat put back into service, albeit with some hand-made guarding to keep out the fingers of the unwary, it would be safe-ish, for me to use, as long as I kept my wits about me.

BUT NOT SAFE FOR ANYONE ELSE unaware of what was underneath.

Only the knowledge of what lurked underneath would be keeping me safe, but anyone else might not have a second chance.

As can be seen from the photo below, all of the wire on the resistors is not only unguarded, but within millimetres of the level of the base. Also, the incoming mains terminals to the rheostat are also dangerously unguarded.

With today's knowledge, it is difficult to fathom how this ever could have been considered safe to use.

IMG_1537.jpg

Edited by Moose

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I certainly did not want to replace the motor, as this is so very visible, all attempts at maintaining the illusion of originality would fail. A solution to the problem could only be achieved with a safer, replacement speed control, which could work with the original mains voltage motor.

Fortunately, these are readily available in the form of a Pulse Width Modulated (PWM), motor speed controller circuit. These will take in the 220V incoming mains supply and provide a variable output of between 50V and the incoming supply voltage. These are well known devices and proven to work with even simple (old) motors.

So, a PWM circuit was obtained (at incredibly reasonable cost), and measured up.

In an attempt to at least have the "illusion" of originality, I was determined to use the original hole for the rotary speed control, as well as the original Bakelite control knob. With the shaft on the rotary potentiometer too short for this, I had to do some more metal bashing.

As can be seen below, I used the old rheostat as a donor, for a short length of it's shaft, which I would mate to the new potentiometer, allowing the Bakelite knob to operate. This was cut to shape and filed to mate with the new potentiometer shaft. This was then soldered together and thus ready for installation.

You can see in the photo, the size and technical comparison between the old rheostat and the new PWM controller circuit.

 

IMG_1561.jpg

Edited by Moose

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Installation of the PWM Controller.

This needed two new mounting holes to be drilled in the main base of the watch machine, the old rheostat fixing points being way too far away to be useful.

Thankfully - and by one of those happy coincidences that just make your day, when they happen - two new fixing holes could be drilled and they would be hidden by the old control knob when it was in place. Happy Days!

As can be seen in the photos below, the new controller occupies far less space and, just by itself, is a much safer solution than the original.  I also hope that motor speed control will be far smoother than with the original. I will still make up an internal cover of sorts, just because I can, and I because am minded to.

I cleaned up the old Bakelite knob a little and ran a little silver paint into the arrow head engraving, to brighten it up. And, as can be seen, the two new mounting holes for the PWM controller are hidden by the knob. Result!

Finally, I replaced the original mounting screws for the old controller, so I did not have holes left on the dial. I think this is the best compromise I could have arrived at, as at least from the outside, the old machine looks to be still original and nothing visibly takes away from its undoubted age. After all - I am dealing with something likely to be over 75 years old and I was trying to take nothing away from that.

That's it for the base unit - so all that remains is to remount the motor etc. to the base and rewire it all.

The jars have been cleaned, I have fitted new rubber seals to the jar lids - I decided against cork as although likely to have been more original - I also had some nitrile rubber sheet to hand and used that instead. I can always refit this with cork later, if I find out for sure these old National machines used cork. :ph34r:

Nothing "build related" for a couple days as I have other work to do, but hoping to get it finished at the weekend. Maybe a short testing video sometime after that.

Thanks for reading.

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A short one today.

I was bothered about using rubber seals in the jars. I have never seen the original seal in a National jar, but thought anyway, that cork would have been far more likely.

So cork it is. Obviously, you can't buy the seals and Elma (etc.) seals are all the wrong size, so the rest of that cork sheet I had was used, and I cut them by hand.

These jars are quite a bit bigger that it's contemporaries and I think that is a legacy from these machines also originally being supplied with clock cleaning baskets, as an option. The jars are around 110mm square with around a 90mm neck size. Don't think I have seen any available as spares anywhere, so likely difficult to get hold of without the purchase of a whole machine. Anyway, I'm happy with these now.

 

IMG_1564.jpg

Edited by Moose

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20 hours ago, Moose said:

 

You can see in the photo, the size and technical comparison between the old rheostat and the new PWM controller circuit.

 

IMG_1561.jpg

That old rheostat looks exactly like the speed controller in a very old train set my Dad passed down to me. It was a huge brick of a thing which sadly failed on its first attempt and I never did get around to getting another sorted but still have the train set.

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Yeah, I can image that sort of thing on a old (very old) train set. It's all a bit "Frankenstein's monster" really. The mains come in and connects the the rotary wiper. It normally rests on the first brass conduction (where it is in the photo). and this conductor is not connected to anything, providing the whole thing with a sort of rudimentary "Off" switch.

Rotating the dial wipes the mains across decreasing amounts of resistance, until the minimum resistance point is reached when fully rotated.

Quite scary really - bear in mind that the red insulated lead is normally connected directly to 220V at all times (unless unplugged), and that it is no more than 5mm away from the metal of the base when installed. There's no insulation between the rheostat and the metalwork of the base, excepting for the insulation on the wire. AND this wire is under continual rotational stress every time the machine is used. The wire I removed had all of its original insulation perished and it literally just flaked off in my fingers when I removed it for replacement.

I actually fabricated a piece of insulation which would sit between the rheostat and the case work, but in the end, my conscience got the better of me - it had to go.

If any one else has one of these National Machines, or is considering getting one from somewhere - I strongly recommend examining this item carefully, or more practically, completely replace it, as I have done.

So unsafe!

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"Safety" would be provided in the form of an earth on the metal case, and a fuse in the plug.

The only protection this actually provides is to ensure you *probably* don't burn the building down, assuming these two things do what they are designed to do. There will still be a big bang and a flash and a lot of magic smoke released if there is a fault.

However, if the earth wire is disconnected (or if the earth pin on the mains plug is nicely covered in a thick layer of insulating crud), then when that red wire with the flakey insulation moves,  falls off, or somehow contacts the case, the entire thing becomes live at mains potential (or perhaps a few volts below, if the crud is mildly conductive).

This can make for a very disturbing and potentially fatal experience if you were to grab the metalwork.

You would probably survive in a modern house with RCD protected circuits, but out in the shed or wherever, and "protected" by nothing but a 30A ring main fuse... you would probably be clean out of luck.

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I agree. If there is one thing I know well (that's not watches, by the way, but I am trying), it's electrics. This thing will be as safe as it's design allows once I'm done. Which means all the lives and neutrals will be the right way around, all terminals sheathed with appropriate insulation, wiring tidied away and secured out of the way, and earth bonding made and checked. Final power consumption checked and then appropriately fused at the plug. Can't imagine it needs more than 3A. Finally, PAT tested to make sure it will at least pass that. I may even label it (for my own benefit), if I think it justified, but I suspect that the basic design means that it would likely fail the visual inspection part of any half competent Class 1 (metal) equipment test.

Incidentally - the fuse is not really there to protect anyone - it's there to protect the equipment mainly. You you be very lucky indeed if the fuse blew before enough current had flowed through you first. Like you mention - Proper wiring and correctly protected circuits are more likely to work. That is assuming they are up to date and regularly tested. It never used to surprise me, the large number of private households that have not had a check in the past ten years or sometimes much more, to see if their house wiring is considered safe. As well of the number of half-arsed "self installed circuits" that are so unsafe, it beggars belief.

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As it happens!

Inspired and interested by this thread and having, for a long time cleaned manually with naphtha and IPA etc, (which has always been adequate for me and more than adequate volume wise as I only work on one at a time). I chanced a bid on one on eBay which I am now arranging transport for and appears to be the same (or close) as yours.

So I'll be checking it and re reading this thread to see what I need to do to ensure it's safe to use.

It'll only be accessed by me and only used when I'm there and unplugged at other times so I'll be looking for info on cleaning fluid and operation instructions once I know it's usable.

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Ahh... well done. :thumbsu:

I was watching this one on eBay and was wondering it it would anyone on the forum. Good for you!

well, I hope there is enough in these simple posts of mine to get you going and refurbish it to the level you want. I am pleased to say that mine is now nearly completed and I just have to do some quick photography on the required base, and then test with fluids.

cant wait to see yours when it arrives and maybe we can compare notes.

G.

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It's bookmarked for delivery Monday, which in reality means Tuesday or Wednesday because, here in the highlands. When the courier says delivery Monday they really mean we'll get it to Inverness Monday and give it to the royal mail because we heard there are dragons and wizards and feudal armies north of there and we're too scared to go any further.

Then royal mail deliver it 'when it gets here'.

I'll have the chance for a quick going over and see if it works but then I'm off with my son for a couple of weeks for the summer hols so it'll be after when I get to play with it properly.

What do you plan to use for cleaning and rinsing solution?

I'm looking at horolene currently. Looks expensive but dilutes 7 to 1 so should be quite economical I hope.

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I think you made a great purchase, and yes, I admit bias. They are very robust machines that have already lasted likely over 60 to 70 years, and with a bit of TLC, should keep on going and providing useful service.

Your machine looks to have the separate on/off switch for the speed control, which mine does not have, but is still identified as a Model 1, as is mine. Yours has a much better makers plate on the front than mine, so maybe has not has as much use. Hopefully then, yours will have plenty of life left in it.

For cleaning fluids, I’m going to go with something very original. I have yet to find out exactly what the National recommended fluids consisted of, but are likely to be similar to what I am going to use. Now I know this risks “many” opinions from others as to what their particular recommendations are, and I respect that. But, all I am going to say is, this was always good enough for Elma, so it’s good enough for me, at least to get me started as a hobbyist. I will likely only do one cleaning a week and not on a commercial basis, so this will do nicely.

For the first wash, I plan to use Elma 1:9 cleaner which, as it is named, is diluted 1 part cleaner, to nine parts tap water. Elma themselves say that tap water is OK as the formulation allows for this.

For the first rinse, I will use de-ionised water, again in line with recommendations from Elma when using the sequence described.

Final rinse will be Elma Suprol. Followed by a spin-off and then heat drying.

I have not found any instructions for the National yet, but as these machines are all so generic, the Elma Instructions for the Super Elite, should easily work well for both the sequence, timings and cleaning fluids. (They are described in the attached instructions.)

Others will also  have their opinions as well, so we can always experiment to find out what works best in our own situations.

I have uploaded the Elma instructions in full, which are freely available for download direct from Elma, Cousins and Walsh, so I do not believe there should be any copyright issues as long as they are reproduced in full.

I’m looking forward to hearing about your National when you have time, and I hope That my ramblings here help out in some way, to get yours back into productive use.

Instructions For HC511 - Elma Super Elite Watch Cleaning Machine.pdf

Edited by Moose

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Thanks for those instructions, I'll have a read through.

Like yourself I'll maybe be doing one a week, perhaps one a fortnight so my biggest Quezon mark is how long a solution will keep once diluted.

The Horolene came to mind as recommended by Mark (of the forum creation) in his video, (which is an Elma as per those instructions).

When I receive it I'll post some images of the undersides and plate etc, the listing said it had a replacement motor and the wiring you can certainly see has been changed so we'll see how it looks.

I'd have preferred another layer or two of baskets with compartments like the Elma as I like to try and keep each component section and screws separate but it might just mean I have to get more of the little mesh baskets I use for endstones.

I'm sure I'll be re reading your tweaks and re config.

Edited by m1ks

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It will be interesting to try the horolene, but I’m sure Mark does not use it in his Elma. In the video he showed something else from a UK manufacturer ( the name was mentioned for it, but I can’t find a supplier). I’m not sure how Horolene would perform in a Machine as I believe  it was originally designed as a soak for clocks. I think putting it into a machine would cause it to foam too much, but I do stand to be corrected on that point.

I think Mark’s reference to Horolene was as an additional step for badly soiled components, but not as a first wash in the machine. Happy to be proved wrong on this though.

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Apologies, I re watched and it's a product called quadralene.

They're based in Derby but no info for product sales on their site.

I may have to rethink that and perhaps look at L&R or Elma like yourself.

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OK - Its all assembled  and looking good.

One minor modification was made before finishing: I have added a ON/OFF switch that isolates the motor when switched off. I have wired it so that the heater can be left on to allow pre-heating. I don't know if this will be a real benefit or not, but it's there anyway and prevents a continuous low voltage AC current be ing applied to the motor, even when not used. To install the switch, I simply drilled a 12mm hole opposite the existing heater switch, so that it looks - to all intents and purposes - like a later version of the same Model 1, which also had the switch fitted sometime in its life.

The first photo shows the underside completely rewired. Incoming mains lead (fitted with a moulded plug and fused @3 amps) enters from the right and immediately terminates in the original connector block, which was in good condition. A new earth bond lead was also fitted.

The internal wiring (orange, twin flex) runs up the centreline following the original cable run. It routes over towards the new ON/OFF Switch. From there, the wiring goes direct to the new speed controller, where there are two terminals: live in and neutral in.

The motor wiring comes from the motor. down the central support pillar, and from the bottom of this, directly to the remaining two terminals on the speed controller: live VAR out, neutral  VAR out.

The heater wires are not indicated as being live or neutral, so one side was simply connected to the incoming neutral terminal on the speed control. Then an additional conductor was taken from the incoming live terminal on the controller to one side of the heater switch. the other side of the switch was then connected to the other wire on the heater.

Finally, I shrunk the heat-shrink shrouding where I had fitted it, to provide additional protection where I considered it useful.

Wires were tidied up and then a visual inspection to make sure that all the neutral's and live's and earth's were connected to the things they should be connected to and that live and neutral were not accidentally transposed anywhere. Then a multimeter check to ensure correct continuity (no resistance) where it should be, and that isolating switches were doing what they should be doing. All good.

IMG_1570.jpg

Edited by Moose

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PAT TEST

Not required in a domestic situation, but I have a tester and it would provide additional peace of mind and help guard against daft mistakes.

Visual checking was already done, fuse in the plug changed for 3 Amp (more than sufficient) and tester connected to the machine.

Everything switched on and simply push to test.

Earth Continuity Test = PASS

Insulation Resistance Test = PASS

Overall Result = PASS.

Yay!

Silly I know, but immensely satisfying in some ways...

(And yes - my tester is calibrated, till April 2020.)

IMG_1569.jpg

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I think you'll find there are polarising views on the necessity of PAT testing for home use. :thumbsu:
Apologies, i'll get my coat.
Looking very nice and neat, looking forward to the first test run, will you be doing a video?
Also, PAT testing, it's one of those bugbear acronyms like PIN number, because, the T already stands for testing, yet we all do it, so we're saying portable appliance testing testing............(I suppose that applies acceptably to musical equipment, especially microphones?)

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The "After" Shot.

So - here it is after the work was done. I think it is a sympathetic restoration and I have tried to maintain the original look and function of the machine and have kept all of the real replacements out of sight. It looks well to my mind whilst still managing to wear it's age well.

TESTING

Speed control - easily controllable, steady speed when set. The new controller does have a different operating range than the old one. The new controller (when the power switch is ON) provides a minimum of 30 volts to the motor. This is not enough to move it in any visible way.

Advancing the controller till the motor begins to move and I measured around 130 volts at the controller output. A slow and steady rotation happens when the control is further advanced and the output at this point is around 150 volts. Around 160 to 175 volts is needed to obtain a steady rotation at around the operational "washing" speed. This seems about right as the motor will rarely (if ever) be operated flat out.

Over all speeds, the motor exhibits no detectable RF interference, according to my RF Test gear, so I'm guessing the new controller is well suppressed as standard, and the motor itself is not noisy.

The heater was also measured for surface heat temperature and self-regulation. Essentially I just turned it on and measured it over a period of around 15 minutes. The surface temperature quickly reaches around 170C to 180C (after about 5 minutes), and seems to maintain that temperature fairly steadily, not really varying by more than about 10 degrees.

Hot enough to burn yourself if you touch it, but well out of the way with the "tunnel" installed. Heat at the top of the tunnel was estimated to be no more than around 45 degrees (rising air temperature) with the tunnel itself remaining cool to touch over a test period of 20 minutes.

My recommendation would be to turn the heater on when you start the first wash and it will be ready for you when needed at the end of the second rinse.

IMG_1571.jpg

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4 minutes ago, m1ks said:

I think you'll find there are polarising views on the necessity of PAT testing for home use. :thumbsu:
Apologies, i'll get my coat.
 

Hopefully you did read the very first sentence in that piece...

;)

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A video maybe... :) (if my upload works)

It's not often these machines turn up, and less often they turn up working, so I feel justified. No commentary, just the noise of the machine itself. Dunno how it will sound to you, but right in front of me, its nice a quiet and completely unobtrusive.

I start from switched off, turn it on, advance the control to what I think is likely to be normal for use in liquids. Finally turning off.

Sorry -  Francis Ford Coppola I'm not!

 

Edited by Moose

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A "close up" sir?

Thought I would just give a close up after I had made some checks to see how much fluid was the correct amount for these jars, as they were unmarked and came with no instructions.

The Elma instructions indicate that the correct level of fluid should be around 1cm above the "suction blade" where the basket is attached. Also that when in use, the suction blades should not become visible, otherwise too much suction will be caused and may result in excessive foam being created.

So I thought I would try to capture this to show what the correct levels and speeds look like. This was done just using plain water.

Firstly with the correct level established. In these National Jars this volume is 750 ml. This is about 75% full.

Then rotation at the correct speed, move to too fast and then back down to nominal again.

The action of the "wave breakers" can also be seen in these shots.

 

Edited by Moose

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So - That's it...

I hope someone gets some information and maybe, a little pleasure from reading this series of posts. 

These Nationals are likely to become increasingly rare, especially working examples, as it seems a certain generation of older watchmakers are disposing of their ancient equipment. Or more likely, and sadly, the descendants of older watchmakers and repairers dispose of their loved one's estates and wonder what can be done with this heavy old bit of junk in Grandad's shed...

I really enjoyed working on this old machine and putting it back into useful service as my own, hobbyists watch cleaner. As well learning a little bit about the business of Mr Saul Lanzetter and his National brand and some of the patents in his name, which may or may not, have led to many such machines and their derivatives being sold all over the world.

All that remains now, is to find a watch of mine that is next in line for a strip down, fix, clean and rebuild and put this little machine back into productive service.

To that end, I'm waiting for the new 7750 video by Mark due anytime now. Ok - now where exactly did I put that tired old Valjoux 7750 when I cleared the decks for this old thing?

B)

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