Just got my MkIII Compass back from Trademark London

Hi all, I've been reading your discussion on compasses, and as a collector of British militaria, it looks as though I've stumbled into the right place. Anyone know anything about J.H. Steward compasses made in 1900? I bought one with leather carrying case and inscribed TH Lovell on ebay years ago, and it looks like the ones in these pictures, only much older/less fancy. the compass card is brown paper with mother of pearl on the outside edge. unfortunately, the compass needs work- the card doesn't turn freely. any info on its history or where i can get it working again would be greatly appreciated. Cheers, Greg p.s. still trying to figure out how to imbed a picture. any thoughts:dunno:

---------- Post added at 08:39 PM ---------- Previous post was at 08:29 PM ----------

Hi all, I've enjoyed reading about compasses- looks like I've stumbled into the right place! Anyone know how/where I can get a Boer War circa 1900 J.H. Steward compass fixed? Mine looks just like the one's in the photos, but of course, much older and simpler. I bought it and its leather case years ago for my Boer War collection, and would like to get the cardboard/mother-of-pearl card working again. I can post some pictures once I figure out how. Any help/information would be greatly appreciated. Cheers, Greg

Hi Greg and welcome to the site. I would recommend posting a photo or two of the compass and we'd be able to better help you. On the surface, it woulds like a pre-WW1 marching compass. If so, they are designed to only spin freely when the release button is pushed. Have you tried that? Marching compasses normally have the card not in contact with the pivot except when you take a reading. Finally, I assume it has radium paint, not brown paper on the card. I would enjoy that compass by not storing too close to where I sleep.

For off-sit picture linking, read here:
https://www.milsurps.com/showthread.php?t=28922
Or if you want to upload pics to this site directly, look here:
https://www.milsurps.com/showthread.php?t=10721

Both of my Prismatic compasses have suddenly developed bubbles. They've been put away since I last used them, pulled them out this Arvo and... Looks as though Trademark and I will be doing a bit of business in the near future.

Hi all, I am Paul from Trade Mark London :)

I've just read this thread, I wasn't aware of it in the past, and I've also posted a comment to Peter's advice for servicing prismatic compasses, which I'm sure he won't agree with :)

I am a compass maker by trade.

A few pointers. The original design for the MkIII compass did not include lid window bars. They were fitted retrospectively where the compass bears an early date, but became optional later on, and from around 1966 when the Mk1 was introduced (MkIII converted to mils) the bars then became standard.

QMs all over Britain freely admit to having used and still using "putty" or mastic to try to fix compasses. I have never understood this, as the actual purpose made o-ring costs just pennies. If a compass leaks it is almost never because of the fibre washer breaking down... fibre washers, by their nature, just don't break down... it's failure of the rubber or silicone o-ring, which must be replaced, otherwise you are treating the symptoms instead of curing the cause of the problem.

Liquid prismatic compasses are precision instruments. Each one comprises over 120 component parts, and they are all hand assembled, balanced and calibrated by highly qualified people. The compasses are certified accurate to within one half of one degree at all four cardinal points, and that accuracy must be re-checked and certified on re-assembly of the compass, as many parts can move during servicing causing a compass to give erroneous readings. Compass servicing involves skills very similar to those of a watchmaker, and certainly we share the majority of our tools.

I don't want to start WW3 with my comments, but I would like people to think very carefully before they proceed with home servicing for many reasons. MkIII compasses contain substantial amounts of Radium 226. This substance is getting close to the Polonium used to kill Alexander Litvinenko in London a few years ago. Radium 226 has a half-life of around 1400 years, which means almost FOURTEEN THOUSAND YEARS to total decay. Think about that. From the late 1960s Promethium was used, which isn't recommended for eating, but is much less toxic than Radium, and now Tritium is used, which is fairly harmless, unless eaten in large amounts :)

Fluid - turps, meths, surgical spirits... all wrong for many reasons. SIRS continue to use Isopropyl alcohol for their G-150 compasses. Many believe that this substance is too volatile and aggressive on the seals, and they may have reason, because the G-150s always seemed to develop bubbles.

I use purified kerosene. It's not very volatile, so it doesn't find its way out... it has slightly higher viscosity so provides better damping, and survives temperature extremes better than Isopropyl alcohol. Whichever fluid you use, however, you MUST match the o-ring to to fluid, as o-rings made for kerosene will not survive long in contact with IsoP. Vice-versa, -rings for IsoP will last longer with purified kerosene.

Where do you get purified kerosene? B&Q, any hardware store... it is transparent lamp oil.

I could go on for hours, but really I only wanted to introduce myself and to put right various urban myths that are doing the rounds here, which will cause damage to compasses.

If anybody has any questions or comments you can address them here in open forum or contact me directly. Compasses are what I make, what I do, it's my job, my trade, and I am happy to answer any questions. There are no "secrets", but there are skills that need to be learned and mastered, just like watchmaking, I suppose, but slightly less complicated.

Quote:

---

Originally Posted by Peter Laidler

I think the UK MoD own or did own the patent rights to the prismatic compasses. Long expired now I expect. And for the purposes of the strip-down we'll be using the later Stanley compasses as they're most like what we've come to expect

As a matter of interest, the bloke who designed/invented/came up with the idea of the triangular prism was the former military attache in Budapest who saw the ZB 27 being used/tested in Hungary and got two examples sent to the UK as late entrants into the trials to replace the old Lewis LMG. The rest, as they say, is history....... He was a Royal Engineers Major who eventually ended up as a Brigadier. I forget his name but his most famous contribution to the Commonwealth was the Bren of course. When I transfer all of my blurb onto this new computer, I'll dig up his name

---

The prismatic viewfinder was patented in London on 5 March 1812 by Charles Augustus Schmalcalder. This gave rise to the prismatic compass, and to optical theodolites and other sighting devices that we all take for granted today. The prismatic compass will be 200 years old on March 5, 2012, in about 9 months time.

---------- Post added at 09:57 PM ---------- Previous post was at 09:52 PM ----------

Quote:

---

Originally Posted by newbieDAN

Where can I buy Purified Kerosene in Australia? :dunno:

---

any hardware store, just ask for non-coloured, transparent lamp oil.

Hi all, just wish to say that I've recently had my G150 serviced, seal replaced fluid replaced with kerosene and not "iso"and its basically saved and restored my compass previously it had this dreadful putty which made the fluid cloudy and resulted in fluid loss, Now a happy man as it is on a daily basis.

I have just made a 19 minute video which you can view by clicking on the link below.

The video is not a demonstration of how to service a liquid prismatic compass, but is an indication of the problems an unqualified person will encounter should they try to do it themselves.

It is a very fast, synthetic view of a job that actually takes several hours, and does not show the calibration, a skill that takes years to learn.

The video will possibly help those who want to try, though it is not intended as a guideline for that purpose, but more it is to point out the dangers of Radium 226, and the fact that once opened a compass immediately loses its calibration, and re-calibration to within one half of one degree at all four cardinal points is an integral part of servicing, and which takes specialist optical instruments and a qualified person to carry out and be able to certify the compass.

The video will also dispel various urban myths, such as using gunge to seal the glass, a special press to seal the glass to the gunge, and types of fluid to use or not to use.

I have published an eBay guide with a vew useful pointers for anybody considering acquiring any used prismatic compass

CLICK HERE

If you think the advice is helpful feel free to give it a yes vote on the eBay page :thup:

I have just viewed 19 mins and 45 secs of excellent footage which was concise and informative and at the same time emphasize the dangers of radium and to steer well clear of damaging putty which was the main reason mine needing to be serviced. Attached are before and after photos of my G150, note also the size of the bubble, Many thanks to Paul of "Trademark London", for a job well done


Attachment 24418

Probably guessed had a few upload probs

Atfter having a few power issues my end, Just wanted to add my compass was returned ,certified to within one half of one degree at all four cardinal points. The service included a total clean, all seal replacement and the five tritium lights along with fluid replacment, only this time with purified Kero and other unexpected touches like replacement base rubber and sticker renewal

I received a 1942 TG Co (The Gramophone Company - later became EMI Records) MkIII in poor condition. It had been "repaired" using gunge and surgical spirits that had become liquid glue that coated the inside and outside of the capsule, effectively gluing the capsule into the lower base - a nightmare. This 1942 MkIII also shows that the original MkIII did not have lid window guards. They were brought in later, and where you see an early dated compass with the guards it is because it was an afterfit.

I have taken the unusual decision to re-light this one. I removed all the Radium-226 based old luminous paint and replaced it with Tritium lamps, where I could, and Promethium paint where the lamps won't fit.

You can clearly see the black rubber sealing gasket around the edge of the sealing glass - in the 1940s they used red rubber, which had a much shorter working life, as it was natural rubber.

Attachment 24422

Attachment 24421

Here's a spares diagram for the Stanley (SIRS) G-150 that was free to download from the SIRS website for years, but was removed with a recent site update. It is approximately valid also for the MkIII and the M-73, M-72 and M-71 liquid prismatic compasses.

Attachment 24429

Great to see you contributing on the forum Paul :) Hope you keep it up!

The Kodak you rebuilt for me works beautifully. The only down side is the wide band of luminova you applied up under the 360 mark on the rotating glass has turned a brown color - almost radium-like. I'm assuming it's been "burnt brown" by residual radium dust or whatever. Otherwise it remains very nice.

If my G150 "quick fix" of topping with ISO fails, I may have to send this one in for a going over as well.

Hi Ron, sorry that happened, but yes it's caused by residual radiation in the aluminium clamp ring. You could buy a little bottle of luminous paint from a model shop and reapply the light, just scrape out the damaged paint, it's harmless, but don't eat it :) or, if you do send your G-150 over, put the MkIII in with it and I'll take care of it for you. All my work is guaranteed, even if it's caused by residual radiation :-)

Hi Paul,

Thanks for the info. I'll try that if it bother me :) As for the G-150, I topped up the ISO about 6 weeks ago and no bubbles have started to form YET. The original varnish seal over the fibre washer filling screw was all gummy on this compass when I opened it up and the screw was slightly loose, so I'm hoping that proper tightening and properly cured varnish will fix the problem. If not, it means I need a new glass seal for the bowl and it will be off to you for basic maintenance. Thankfully, it's otherwise in very servicable shape and no putty :)

Hi Ron, the "varnish" on the filler plug screw is a sure sign it has been buggered about with... possibly another QM :yikes:

Before you top up with Isopropyl alcohol it's best to ensure that what is in there is still Isopropyl alcohol, because if somebody has had a go at it and used meths, turps, or surgical spirits, then putting something different in can cause the two fluids to separate, each having their own specific gravity, which will cause uneven damping, at best, and at worst it could possibly cause other issues.

However, beware of compasses that have varnish on the sealing plug screw... it's a classic QM signature :yikes:

Hopefully no more bubbles will appear.

Hi Paul,

Every ex-MOD G150 I have seen (a sample of three - I know, very scientific - most I see regularly are Canadian issue) has a lacquer or varnish over the plug, presumably to mark that it hans't been tampered with? The two compasses I canibalized to make a good one were both written-off MoD compasses, one had a broken case, the other had issues with the bowl. Put good bowl in good case plus swap a few parts = serviceable compass - lol. See the pics furhter up the forum. Both definitely had MoD ISO in them, I didn't use new ISO, I took a little frm one compass to top up the other. As I said, 6 weeks after the work, the G150 still pointing identically to my Kodak MkIII you recently rebuilt for me and no bubble has yet appeared in either the Kodak or the Stanley. If one does turn up, I'll send it in for re-gasketing and a top-up :) If the G150 leaks, it will likely do so in the first few months I should think. I'm hoping it was just the loose filling plug that was the culprit.

Cheers,
Ron

Great news! The G-150 ex-factory does not have varnish... it simply isn't needed if it is put back together correctly. The G-150 was the leakiest compass probably ever made. Isopropyl alcohol has excellent properties for compass use, but it is so incredibly volatile that it will find a way out... should be called IsoHoudini alcohol :) That is probably why people have tried many tricks to stop the leakage over the years, but the best one would simply have been to change the fluid and use something equally suitable, but considerably less volatile and aggressive on the seals. Yours may be good for a few more years yet, and even if you have to top it up every six months for the next few years, that's money saved. A service is the last resort, or necessary if you really need to use the compass at night and the lights have failed due to age. Keep topping up, if necessary, and the compass will be fine.
This seems a very friendly forum... it discusses many things outside of my field of competence... I know how to use firearms but I don't collect them or restore them... so I'm fairly limited to helping people with compasses and various other antique scientific or navigational instruments, but if I can help somebody in any way then I'm happy to join in.

I have just moved my website, TRADE MARK LONDON, to a new server, the service offered by the old hosting company was getting worse and worse, and I took the chance to totally re-write the website. There is a lot of new information for compass collectors, including the chance to view the first 320 pages of the book TRADE MARK LONDON in flipbook format on screen, or to download the full high quality version in pdf for printing or viewing on your screen, all 538 pages of it, which I have now basically given to the public domain, and is free to download.

If you collect compasses then the updated site is certainly worth exploring.

Click on my signature link to visit the new site.

This is so cool. I am now hunting for a compass of my own. they are a fascinating little instrument. Sort of the GPS of it's time. I have not read the entire thread and if the answer to my question is in it I apologize now, but how much cash would I be spending on a fair to good example? And where is a good place to start looking?

I don't know about prices Dave N but they really are superb instruments, built to last. In fact, we used to say '....built by the people who built Stonehenge!' I'd get one that is slightly defective in that it is complete but had aerated - got a bubble in it. With a bubble, they are defective and as such you can negotiate. While I have gone threough the very basics and you could do it yourself, especially if you can be bothered to build a degassing tank and source some isopropy, the GOOD news is that trademark on this forum can give them the works.

Might I be so bold as to suggest that you don't polish the case back to brass but leave it black or khaki green - as it should be

Hi Dave, I hope I can help you by suggesting that you visit "Trademark London", site and view what Paul has on offer and I'm sure you will be impressed and save yourself the bother of buying a lot of hassle with the likes of gummy, gungy masticky problem and possibly damaged compasses, which I'm sure Paul would not be too keen on refurbishing (My opinion) as he has mentioned that compass tecnicians probably won't entertain other peoples repairs. I wish I had bought from "Trademark London " in the first instance.

Hi DaveN
Please click on the link in post 108 of this thread for advice on buying a used compass.
It is highly inadvisable to purchase a compass with a bubble, or even one without a bubble if it doesn't come with a current certificate of service and calibration, and a guarantee.
Bear in mind that a full service will cost you GBP 130 upwards, and if you combine that with the cost you paid for the old compass you might just as well buy a new one.
Remember also that no compass maker will repair other people's mistakes, so if you have a go yourself and get it wrong then you are stuck with it.
Please read the link in post number 108, not far behind this one, and it may help you.
Good luck.

Hi Paul, have not long read the email you sent me which makes for some interesting reading which others could benefit from as it is enlightening and gives one a choice as to which road to go down when it comes to compass repair.

I'm saving up for the Stanley L1A1 trade mark has just put in his shopp - real eyecandy!!!

Hello, I got this compas that looks exacly as a MKIII but without military markings.
It was my grandfather's who was a prospector in the 50-70's
It is in great cosmetic condition never openned but the bowl is half empty.
The brand is Casella
I post it to share with others and I would like to know when it was made.
I'm terrified to learn it is potentially highly radioactive. :ugh:
Any other input welcome.

Thanks

Alain

https://www.milsurps.com/images/impo...compass1-1.jpg
By lutah at 2011-10-18
https://www.milsurps.com/images/impo...compass2-1.jpg
By lutah at 2011-10-18
https://www.milsurps.com/images/impo...acompas3-1.jpg
By lutah at 2011-10-18

Paul's left this forum mate... says he won't be back because they continue to encourage a member who tells people to play with Radium, and censors the good guy who criticises that advice - slow motion suicide he says.

It's just a shame that there isn't a place for a personal reply Grads.............. Your one sided comment is absolutely outrageous. On the other hand, maybe it's a GOOD idea that there is no facility for a personal reply. What bile...... and second hand bile at that too............................

Thanks for the info, live and let die I say
I think I'll get rid of it anyway

Who on here was advocating opening up compasses with radium in them?

Not just open them but PLAY with it.............. Money where your mouth is time Grads.......... Time to put up or shut up I'd say.................

Moderator Note: It appears that members with the user names trademarklondon and grads are one and the same person, using the same computer and same IP address.

As a result and due to several past instances of abuse we've experienced with this kind of activity, several years ago we instituted a policy where we do not permit individuals to register or use multiple usernames and identities to access the site.

Both accounts have been placed in moderation awaiting further explanation from the member(s) …

Regards,
Doug

I bought a Prismatic Compass via that well known online auction site - ex Brit Army. It's in the 'Forest Green' livery. I understand that the compass would of been 'swung' for say UK or European operations and hence has what I believe is called a Compass Dip due to being in Australia. Is of no consequence if one allows for the dip.

I've so far dismantled it and intend to strip it back and then restore orobably in the original green as opposed to the satin black. I'm not going to change the liquid as as stated earlier that to do the task correctly it must be done in a vacuum.

Anyway, this thread has been a wealth of knowledge, cheers.

Oh, if anyone has an original web compass pouch they wish to sell, I'd be very interested.

Copmpass pouches regularly appear pretty cheap on that same auction site

Does anyone know of a source for parts for both the M73 and MKIIIs ?

I find it silly to have to send it back to the UK for a complete over haul when all that needed is a prism guard screw. :mad:

Just send me your address and I'll see what I have in my spare parts tray..........

Hello, I hope that there is still someone interested in this thread that may be still around, if not then perhaps i can be directed to another thread containing Prismatic Compasses.
Well, I have just recently gotten into collecting Prismatic Compasses and reading anything and everything about them from various sources. This site was what I thought would be a gold mine of information, and it was till I came to the last post that was posted some time ago. Anyway. I have in my possession a Canadian Kodak Company, MKIII. There is not much information on the net about these particular compasses and I was wondering if Kodak had made any of these for Non-Military use? The one I have is in fair condition with one pot screw missing and the lid window and associated screws are also missing. The thing that has me questioning its original use though is the fact that as the pictures show below, there is no broad arrow, no date or any serial number to be found. it was my Grandfathers and he was an engineer in WWII, but without these markings I am unclear if this was an issue or not. I see in the few online photos of these Kodak models that they seem to lack a date, and one other has lacked a serial. Any help would be great. Also, I am looking for a source for parts, ie. screws and seals, ets for the MKIII models, be they Stanley, FB&s or any other manufacturer of the MKIII. Thanks and I hope to see this thread revived..

https://www.milsurps.com/images/impo...b0988a76-1.jpg
https://www.milsurps.com/images/impo...b0ec1d74-1.jpg
https://www.milsurps.com/images/impo...0ce89d57-1.jpg

Welcome to our site DaedalusWren!

Yes, you did it correctly... When you respond to a topic from an old thread it brings the old thread to the top again and we can see there is a new post.
We always like new info. (good pictures too) :thup:

Regards,
~ Harlan

I would imagine that they were all made to the same spec. The current window is(?) available from a spare parts supplier on that auction site (look at 'prismatic compass') and the screws were a small 10BA size with a large diameter head. Should be simple for a good model engineer to make - or be available from a model engineering supplier. Same compasses are still in use today but graduated in mils. Nope, I never got my head around them either

Please accept my apologies for resurrecting an such an old thread (especially for the most selfish of reasons) but being as this is the most comprehensive knowledge base for British Mk III compasses it would be foolish to start anywhere but here!

I'm in the process of breaking down a 1943 CKC MkIII prismatic compass for the purpose of restoring it to factory specifications. I've not done a compass restoration before but have tried my hand at many Swiss watches over the past year and a half and have confidence I'm up for the task provided a little guidance is in the offering.

https://www.milsurps.com/

I've broken down the above compass to most of it's constituent parts but am a bit flummoxed as to how the slide for the prism lens comes apart. The slide is secured behind a small sheet metal square with two small screws. When the screws are removed the square can move up and down a small amount but cannot be removed from the slide bracket as it's engaged in a track and cannot be moved either up or down enough to exit the track before it collides with the prism hinge or the bottom of the slide assembly.

https://www.milsurps.com/

I certainly don't want to force things and break an unreplaceable part so anyone who might have an interest in this thread and perhaps some previous experience working with MkIII compasses, I could sure use the help!

Thanks in advance for any assistance you may have to offer. I've read through every page of this thread before begining my work due to the knowledge the membership has on offer. :)

Also, if you are interested in reviewing the images of the restoration I've uploaded them to my public Dropbox folder here. I appreciate any feedback positive, negative, or otherwise (but hopefully constructive) as I progress.

:beerchug:

With thanks to Advisory Panel member Peter Laidler, a new article has been added to the Technical Articles for Milsurp Collectors and Re-loaders (click here).

COMPASS, PRISMATIC, Mk3 (by Peter Laidler) (click here)

Quote:

---

Article Extract .....

There has been a bit of interest on this forum about these prismatic compasses and the variations that have emerged since they were introduced in……….., well, whenever it was, they seem to have been around since, well, forever! Certainly since my time in the Army, first learning to read a map and compass as a Cadet at school in the early 60’s. They’re of some significance to the Lee Enfield story because the compass was a supplementary issue alongside the equally important binoculars and wristwatch for the snipers. While they’ve all changed slightly, they’re still very similar …... article continues in link shown above .....

http://photos.imageevent.com/badgerd...pass%20001.JPG(Click PIC to Enlarge)http://photos.imageevent.com/badgerd...pass%20004.JPG(Click PIC to Enlarge)http://photos.imageevent.com/badgerd...pass%20006.JPG

---

After you click on images to ENLARGE them, you may find they automatically size smaller in your browser's window making them harder to view. The auto sizing is your browser's way of keeping images entirely within the screen size you have set. Move your mouse pointer to the bottom centre of the pic and you will see an options panel appear. There will be a small square box next to the large X, which will have a pointer arrow sticking out of it. If it's illuminated, it means the pic you're viewing can be enlarged, so click on this box and the pic will EXPAND and open to its normal size.

Peter has added a personal request in regards to this article.

Note: If you have any questions or don’t understand something or my instructions are ambiguous then please ask on the forum and NOT by PM (Private Message). That way everyone will get the benefit of the question and answer.

Regards,
Doug

If you bend that small sprung plate - the plate you speak of, held with 2x screws - a slight amount it will rotate out of the slots. Don't worry about it because it';s sprung material and it'll go back to shape. It will also have to be sprung away to replace it. The screws will hold it all back together afterwards. If you really need another sprung plate for the cost of the postage, let me know.

What are you going to use as the liquid damping medium?

Quote:

---

Originally Posted by Peter Laidler

If you bend that small sprung plate - the plate you speak of, held with 2x screws - a slight amount it will rotate out of the slots. Don't worry about it because it';s sprung material and it'll go back to shape. It will also have to be sprung away to replace it. The screws will hold it all back together afterwards. If you really need another sprung plate for the cost of the postage, let me know.

What are you going to use as the liquid damping medium?

---

Thanks for the follow-up guys! I did manage to get the spring plate removed after biting the bullet and giving it a little bit of a bend. It's just a bit of copper and when it came out, it did so without any damage whatsoever.

I'm going to use purified kerosene as the dampening fluid. The kerosene seems to agree with the printing on the compass card as I used it as the medium for cleaning the card without any damage occurring. The card had some rust staining on it which was removed fairly easily with a soft artist's paintbrush. This work was performed while the card was submerged in kerosene though as I didn't want to get any radium dust floating around the workspace.

Please accept my apologies for the broken image links in my earlier post. Image hosting always seems to be a struggle (for me) when it comes to posting in an new forum. You should be able to follow the progress via the link to my public DropBox folder though (see earlier post).

Thanks again for the help. The project is coming along nicely and much of the credit goes to data found in this forum. :)

Apologies wrong heading it should read Spares for MKIII

Hi Guys new to this forum I registered here to be able to read all the guides and watched the vidoe and several other forums on these MKIII compass and now I have a questions questions that I don't see mentioned anywhere.:help:

Before I disassemble it and attempt the accuracy of what Paul is mentioning

The bowl sealing ring or gasket does anyone know of a replacement supply that has these readily available or a part number of an B-profile o'ring gasket?

What dimensions are the fibre washer?

Paul mentions tritium lights but these seems to stick on what have other people been using to restore the lights on the compass?

I have been looking at restoring an interesting MKIII, it was manufactured in 1939 and it has three names scratched into the lid so I can only assume that these were issued to various troops. I looking to trace its history and restore it. Anyone know how I can find out from MOD records who were issued the compass. From there it will be a case of tracing the troops service records.

Quote:

---

Originally Posted by Gedrog

Apologies wrong heading it should read Spares for MKIII

Hi Guys new to this forum I registered here to be able to read all the guides and watched the vidoe and several other forums on these MKIII compass and now I have a questions questions that I don't see mentioned anywhere.:help:

Before I disassemble it and attempt the accuracy of what Paul is mentioning

The bowl sealing ring or gasket does anyone know of a replacement supply that has these readily available or a part number of an B-profile o'ring gasket?

What dimensions are the fibre washer?

Paul mentions tritium lights but these seems to stick on what have other people been using to restore the lights on the compass?

I have been looking at restoring an interesting MKIII, it was manufactured in 1939 and it has three names scratched into the lid so I can only assume that these were issued to various troops. I looking to trace its history and restore it. Anyone know how I can find out from MOD records who were issued the compass. From there it will be a case of tracing the troops service records.

---

I'm sure Peter will be able to supply better answers to your question but here's my stab at them:

Regarding the o-ring, I've not found the profile Paul refers to in his post but I'm sure they are out there somewhere. You can try contacting Paul via his website but after reading through his disclaimers it seemed he might not be too receptive to such inquiries. I've decided to go my own route and have sourced some Fluorosilicone o-rings which have a diameter of 39mm. I haven't filled the bowl yet as I discovered one of the holes for the retaining screws was stripped out and will need to be tapped so I cannot yet say whether a regular o-ring will work.

I measured up the fiber washer that came from the bowl and it's 5mm OD, 3mm ID, and .75mm thickness.

Tritium seems to be the way to go since the tritium lights will glow without recharging. I've used both luminous powder and tritium tubes in my repair but I think you can go either way.

Unfortunately I cannot help with MOD inquiries as I'm a Yank(ee) and have no idea how one gets such information from the MOD. Perhaps this is another question that Peter can help with though.

Good luck with your project!

Use a standard neoprene O ring as the seal but due to some different tolerances between the bowls you MIGHJT have to use an O ring below the glass and one ABOVE the glass. THEN bring the ring down using the 8 screws. We were taught a special sequence of tightening. Here goes. 12o'clock/1st screw down to finger tight, miss two screws, then 4th screw, miss two then 7th screw, miss two next screw and so on slowly tightening down as you go around. Like tightening up a cylinder head the CORRECT way. I've never done i and we certainly wouldn't be allowed to do it in the workshops, but you could try a small suitable O ring for the sealing screw.

Pass no comment on the illuminating but tritium is the way to go. You will never find out who used your compass unless you had an Army number to match

Thanks Peter and RayMeoller

Thanks for the information guys really appreciate it, so a few more questions
What thickness O-Ring do you guys use?
I managed to locate a source for D-Ring seals, which I saw mentioned on another site although they are not really commercially readily available. D-ring Seals | Rubber D Rings | Precision Polymer Engineering any thoughts?
I have tried to locate tritium lights, readily available for instruments for commercial purchase, however I have had no success, this company sells them but it isn't like a shopping cart situation I haven't ordered any as I suspect they only deal in bulk orders. Light Source | BETA Light Anyone else have a better source? Otherwise I was thinking of just using this mixed with a decent lacquer
SFXC® Glow in the Dark Photoluminescent Pigments 100g - 10 Hour Glow Time - High Grade Strontium Aluminate: Amazon.co.uk: Kitchen Home
I found this and and thought bargain but after I got it its stipulates that direct sunlight contact will cause it to go yellow so testing a few samples at the moment
2 x Pratley Kraftex Pratligo Adhesive Epoxy Craft Seal 200ml 96102 New Lacquer Varnish Sealer: Amazon.co.uk: Kitchen Home
I mixed the two together to make a thick paste and applied to a couple of corks and will then test them in Isopropyl and kerosene to evaluate the effects plus long term exposure to the sun.
But if anyone has a better solution I am all ears

I have been trying to optically align the compass by using some technology
I have a DSLR Nikon D3200 a £16 copy stand (not very stable but I try to align everything as level as I can ) and a £6 Macro lens adapter I use a free app called DSLR Dashboard so you get the picture.
I align the needle that points in from the case part with the glass
This is a decommissioned Stanley G150 I just received so I can see the issue of getting it aligned the one with the bubble is one I have now used this alignment method on but I am not sure if I am doing it correct maybe the experts can advise if I am doing it right. ( THis is after spending overnight in the fridge, fridge before there was no bubble so will refill and overnight again.
Attachment 86484

I really don't know what you're trying to do but one thing I can tell you is that it's no use doing or trying to do anything with a bubbled compass. Stop faffing about trying to find the D seals. Just use neoprene O rings. One below and if necessary, 1 above the glass then tighten the bezel down equally over 4 or 5 rotations of the bowl. That's what we've been doing ever since I remember

Hi Peter I am trying to find the best way of doing the alignment and best way to seal up the compass so it can be preserved for the next generation.
At the moment I am practicing on a couple of Stanley G150 compasses that I got of Ebay for next to nothing and having a bit of fun doing it.

I am not yet sure what the best thickness O-Ring is to use so I have ordered some 39mm by 2mm as my question has not yet being answered
Failing that I will order some 39mm by 3mm O-Rings
What is the best Glow paint or glue to use so that I don't end up with a milky soup inside the compass?
Sources for the bigger Tritium lights the smaller ones are easy to find it's the bigger its the 4X9mm tritium light that I can't seem to find

I have a MK111 that has sentimental value as it belonged to my Grandfather who served in WW2 in the ANZAC's so I want to restore it to full working order but because it contains the Radium paint I am struggling to find someone that will work on it.
So I decided to give it a try but I don't want to mess things up. I was hoping with the vast knowledge and experience of the forum members I would be able to easily find the information

As usual I will waddle in and ask what are you trying to align, the compass aligns itself by its very nature to magnetic North/South as Peter said having a bubble in there your wasting your time I cleaned a couple of mine up using a syringe + long tube to get most of the gunk out of the bowl and refill with Isoprophyl as a dampening agent did a thread on it ages ago.
I did not want to open the bowls of them with radium present they are also a good distance from where I sit in my room

Hi Cinders

The reason I opened this one is the night light has came loose on the compass card and was floating around in the compass bowl
If you look at the attached picture I am using the Camera App to align the pin at the bottom of the bowl with the pin that the compass needle rest on then I install the compass needle and lastly the glass and align the lubber line on the glass . The compass is clamped in place so it does not move during this procedure so I am making sure I have this alignment correct.

I looked at one where the compass bowl have not yet been opened and realised that the if I align the app with the lubber line the the needle was not fully aligned so that was an interesting observation

I still have questions about the thickness of the O-Ring in the one with the Bubble that was filled up again and it was good but I re-used the seal not a good idea

Is this the same method everyone else is using of aligning it when they open the compass bowl?
Does anyone know the thickness of the O-Ring?
The following questions is avoid is based on the concern I have that Kerosene may dissolve the glue or paint.
Whats the best glue to stick down the night lights in the Kerosene?
Whats the best glow in the dark paint people have found as the Mark 111 has glow paint on the compass card rather than a night light?

You need Isoprophyl bloke hardware stores should stock it in 150ml bottles I think thats what Peter L said was the dampening agent ages ago from memory I got mine from Bunnings but seeing as your in the Sahara you may want to try the local Bazaar:madsmile:

According to the experts you can use either but I picked some stuff up at the bazaar that the local was brewing and guaranteed it was 99.999% its got a fruity body smells a bit like dates

Gents,

Apologies for resurrecting an 11 year old thread, (that i'd contributed to)

I've acquired another Mk111 prismatic compass in need of repair. On disassembly, I've found that the pivot pin the magnet sits on has corroded away completely, only the nut is left.

Any Aussies here have an idea where I could get a replacement locally ?

Thanks in advance for any help.

Probably a clock-maker/water repairer of the old school could produce one for you.