M73 Prismatic Compass

[johnboy]

Hi,

Having a surf around and I noticed that a trader has FB M73 Prismatic Compasses for sale for what seems like a reasonable price...

http://www.ebay.co.uk/itm/Francis-Ba...item35be90d06b

They are calibrated in Degrees rather than the more common Mils..

No Connection to seller etc...

[HillBill]

Nice.. think i'll be having one of those.

Much obliged.

[Wayland]

Good price for a great compass.

I wonder how old the tritium lights are?

[HillBill]

Can they be replaced if they are too old? I've read somewhere that all parts are replaceable.

Good price for a great compass.

I wonder how old the tritium lights are?

[santaman2000]

Can they be replaced if they are too old? I've read somewhere that all parts are replaceable.

Maybe. But if so, I suspect that it might be more expensive than a new compass. That said, how many of us are really going to be doing night ops anyway?

[Silverhill]

Johnboy! How did I miss these? I've been watching the bay for one for months now and taking in various threads on BCUK about what to look for when purchasing etc. I've been reluctant to pay higher prices for an old reconditioned one or buy a cheaper older one only to find that nobody will touch them due to the radiation, despite wanting one with a bit of history.

I've read that the repair costs and replacement of the radium elements can be more than a hundred quid in some cases, so the one Johnboy has linked to is a bargain in comparison. Here's a couple of links to previous BCUK posts on the matter.
http://www.bushcraftuk.com/forum/showthread.php?t=50195
http://www.bushcraftuk.com/forum/showthread.php?t=1250

And another to a repairer of compasses:
http://www.trademarklondon.com/Compa...irs/index.html

Thanks again for the heads-up Johnboy.

[HillBill]

I like to start my hikes before sunrise, so i can be up somewhere with a view as the sun comes up. The same applies in reverse. many a time i have sat to watch the sun set with distance still to travel. Highlights of my day The new compasses are £300, so even if cost me £100 to restore the trits its still worth it.

Maybe. But if so, I suspect that it might be more expensive than a new compass. That said, how many of us are really going to be doing night ops anyway?

[santaman2000]

I like to start my hikes before sunrise, so i can be up somewhere with a view as the sun comes up. The same applies in reverse. many a time i have sat to watch the sun set with distance still to travel. Highlights of my day The new compasses are £300, so even if cost me £100 to restore the trits its still worth it.

The Cammenga tritiums are onl $96 new directly from the company. Even with postage to the UK, that's still quite a bit less than 300 quid; probably less than the 100 for reburbishment. www.cammenga.com In choice of 3 colors.

I like to hike at predawn too; at least from the truck to the hunting stand. What I meant though, was how many of us are actually doing so in a stealth mode without a flashlight to read the compass?

[HillBill]

True enough. But i hate using flashlights when walking, as i prefer to keep my eyes better adjusted for the dark. Much happier being able to make out features all around than just whats illuminated in the beam of the torch.

The Cammenga tritiums are onl $96 new directly from the company. Even with postage to the UK, that's still quite a bit less than 300 quid; probably less than the 100 for reburbishment. www.cammenga.com In choice of 3 colors.

I like to hike at predawn too; at least from the truck to the hunting stand. What I meant though, was how many of us are actually doing so in a stealth mode without a flashlight to read the compass?

[johnboy]

Re the tritium lights..

If they are shot they can be replaced.

Pyser SGI offer a complete service for about GBP 90.00 ( quoted to me 3 weeks ago) which includes replacement of all 5 of the lights along with replacement of the seals and pressure test of the seals replacement of missing screws calibration etc

More serious faults will cost more to fix..

http://www.pyser-sgi.com/

Another provider of service work on M73s is a company called trademark london.

http://www.trademarklondon.com/

M73's seem to be the Prismatic to go for far nicer than the US issue Lenstatic.

However when it comes to protractors which you'll need to use a prismatic with a map I prefer the US GTA 5-2-12 type than the RA protractor...

[demographic]

Just spotted THIS on Ebay, now am I just being a bit thick* or is there a marked lack of degrees on that compass? Looks like the numbers only go upto 60?

I've heard of degrees (obviously) and mils but a full circle having only sixty points/degrees/measurements? New one on me.





*Won't be the first time and I'm sure it won't be the last either.

[johnboy]

The Soviets and some Arab nations that were influenced by the Soviets use a compass with 6000 Mils graduation.

Thats what you have found there...

[Totumpole]

Cheers for the heads up - Snapped up the last one from the sellar. Now to learn how to use it.........

[Wayland]

Cheers for the heads up - Snapped up the last one from the sellar. Now to learn how to use it.........

I did a short piece on my site about them if it's any help.

They are pretty staight forward though, I'm sure you'll soon suss it out.

[swotty]

I did a short piece on my site about them if it's any help.

They are pretty staight forward though, I'm sure you'll soon suss it out.

Thanks Wayland....great article

[santaman2000]

...M73's seem to be the Prismatic to go for far nicer than the US issue Lenstatic.

However when it comes to protractors which you'll need to use a prismatic with a map I prefer the US GTA 5-2-12 type than the RA protractor...

I've never seen an M73 other than the picture in this post so I cain't really compare them head to head. However I use the Cammenga without any protracter. Rather when it's folded completely open you can lay it on the map and use it as it's own protractor just like an orienteering (baseplate) compass. All that said, I'd generally prefer a true baseplate compass to any other, but comparing them that way seemed more like comparing apples to oranges.

The M73 may well be a much better compass. But even if so, I'd have to be using it professionally and daily to justify 300 pounds vs $96 (TBH even that's a lot to pay for a compass, mine was issued)

[Wayland]

As mentioned in my article, I wanted one just because I'd enjoyed using one before.

It's a bit like buying a car. My old banger gets me where I want to go but I'm sure a new Landrover would be more fun.

I have to admit though, it's the only compass I've ever taken on a plane that hasn't developed an air bubble.

[HillBill]

Quality and reliability are what the francis barker compasses are all about. Its a pride of ownership thing. You know that when you hold it you are using one of if not the best compass ever made. It has a very rare quality these days, and that quality is "Made in England"

Id quite happily pay the £400 for the all brass version here and i'd never use it.
http://www.stanleylondon.com/Compass...8.htm#M73BRASS

Which gets me to thinking, with the M73's being made of brass, i wonder if i cleaned the paint off and polished it up, would it be similar to the all brass one? I know the bezels will be different, but the rest......?

[johnboy]

Quality is that the francis barker compasses are all about. Its a pride of ownership thing. You know that when you hold it you are using one of if not the best compass ever made. It has a very rare quality these days, and that quality is "Made in England"

Id quite happily pay the £400 for the all brass version here and i'd never use it.
http://www.stanleylondon.com/Compass...8.htm#M73BRASS

Which gets me to thinking, with the M73's being made of brass, i wonder if i cleaned the paint off and polished it up, would it be similar to the all brass one? I know the bezels will be different, but the rest......?

My M73 has an alloy case with brass fittings. YMMV

Ive had a couple of US issue Lenstatics a Stocker and Yale and a Cammenga. From a it's a compass use ability perspective they are fine..

A M73 is a much better quality compass than a Cammenga in terms of materials used etc... Is it any more accurate? In real world terms probably not..

It is a very very nice bit of kit to use..

[santaman2000]

As mentioned in my article, I wanted one just because I'd enjoyed using one before.

It's a bit like buying a car. My old banger gets me where I want to go but I'm sure a new Landrover would be more fun.

I have to admit though, it's the only compass I've ever taken on a plane that hasn't developed an air bubble.

I never had an issue with air bubbles as all my compasses have been induction dampened. I do see the pride of ownership thing though. Just never applied it to compasses before but I suppose it should apply there as equally as any other bit of gear.

[HillBill]

For me, its the most important bits of kit that get priority when to comes to expenditure. All the essentials if you like. Compass, boots, knife etc.

I never had an issue with air bubbles as all my compasses have been induction dampened. I do see the pride of ownership thing though. Just never applied it to compasses before but I suppose it should apply there as equally as any other bit of gear.

[Totumpole]

I did a short piece on my site about them if it's any help.

They are pretty staight forward though, I'm sure you'll soon suss it out.

That is a nice little starting guide, thanks.

[HillBill]

Ah fair enough. Not much weight difference between the all brass and standard black though. Shame really Saying that, i could easily make a brass case with the lathe and milling machine. Are the cases easily removeable do you know?

My M73 has an alloy case with brass fittings. YMMV

Ive had a couple of US issue Lenstatics a Stocker and Yale and a Cammenga. From a it's a compass use ability perspective they are fine..

A M73 is a much better quality compass than a Cammenga in terms of materials used etc... Is it any more accurate? In real world terms probably not..

It is a very very nice bit of kit to use..

[johnboy]

Yep the compass housing is removable from the case. But the case has the prismatic prism and lid hinge attached.

Not sure if the case from an older Mk III would fit. But you have to be careful with the older compasses as they used quite a bit of Radium in them.....

HTH

[santaman2000]

My M73 has an alloy case with brass fittings. YMMV

Ive had a couple of US issue Lenstatics a Stocker and Yale and a Cammenga. From a it's a compass use ability perspective they are fine..

A M73 is a much better quality compass than a Cammenga in terms of materials used etc... Is it any more accurate? In real world terms probably not..

It is a very very nice bit of kit to use..

Yeah, one of mine is actually S&Y. Cammenga is the one that gets all the press time so it's the one I referenced. TBH I don't know if S&Y are even still made. I cain't find a websie for them although I'm getting a lot of hits to surplus sited for them.

[udamiano]

Here a picture of my one and can just say "worth every penny"

[johnboy]

That looks a bit neat and tidy...

Mine is well worn....

OS explorer 221 by any chance??

[udamiano]

That looks a bit neat and tidy...

Mine is well worn....

OS explorer 221 by any chance??

221 Explorer.. yes indeed it is. hehe it gets kept in it own little leather bag, when not been used, so kept in good condition, but does get used pretty much on a daily basis, including tonight.

[udamiano]

you can just see Rough Close by the North point

[johnboy]

Yep got it so Rough Close is approx 300m x 400m.?? It's hard to see the grid lines in the photo