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Scottish Lamp / Signal Light

Started by TG, May 11, 2019, 02:16 pm

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TG

May 11, 2019, 02:16 pm Last Edit: May 11, 2019, 03:14 pm by TG
Avoncroft_signal_lamp.jpg
Lamp on the box at Avoncroft Museum

I would love to find more detailed information about this type of lamp - does it have another name?
Do we have a diagram or dimensions on TB? I know a couple of the members here own one of these lamps - would someone be happy to provide more information?

Quick scan from page 78 of The Rise and Fall of the Police Box:
signal_lamp_page.jpg
It comments that the top is a gong - so that's why there is a gap below the dome - to allow it to ring?

As Pete d noted in the Mark 1, Mark 2, Mark 3 thread:

Quote from: pete d on Sep 04, 2010, 06:06 pm
...the Glasgow boxes had the ingenious idea of placing the bell on the very top of the beacon, making the sound of the ringing phone much easier to carry over distance. I'm not sure that many people realise that that's what the dome of the beacon on a Glasgow box actually is - a bell.


Perhaps like a longcase clock bell? with a domed hex nut on top.

steel_clock_Bell02.jpgdome_nut.jpg
sorry slight mismatch with the size of these but hopefully you get what I'm thinking (If I was thinking of trying to make one).

Mark

Hi TG,

Not sure if mine is a later version but the dome doesn't have a massive gap like the ones pictures at Avoncroft.
IMG_20190511_201035.jpg
That said, it does look nearer to the illustration so perhaps perhaps mine is an earlier one and the ones at Avoncroft are later "new and improved" versions?

The dome is a gong but I've never seen a picture of the mechanism and striker that would make it ring but I've just gently rung the one on mine with a small hammer and it makes a quite pleasing ring with quite some reverb .

IMG_20190511_200856.jpg
I would guess that is the bracket a striking mechanism would attach to as it doesn't serve any other purpose.

kutan66

Quote from: Mark on May 11, 2019, 07:17 pm


Not sure if mine is a later version but the dome doesn't have a massive gap like the ones pictures at Avoncroft.


Maybe the gap is just because its not been re-assembled properly?  Due to corrosion or paint?

domvar

The dome is also a bell but not all of them have the striker installed.  I suspect this may account for the gap.

Mark

May 12, 2019, 05:55 pm #4 Last Edit: May 12, 2019, 06:04 pm by Mark
Well at first I was thinking it unlikely as I imagined the striker mechanism would bolt to that bracket from within however I got to wondering and went armed with my largest spanner to try and remove the dome.

Well the spanner was way too small but it would appear some previous owner has applied liberal amounts of copper grease as I got both nuts off using nothing but my hand!
IMG_20190512_183047.jpg

Now that doesn't really help with how the bell was meant to be attached but it does help prove that the gong can be put on higher.

I've just looked at the picture of the Glasgow Box posted above and noticed it's only got one bolt on the top so perhaps the other bolt was put on beneath the gong. The ones in the illustration appear to show two bolts if you look close.

IMG_20190512_190017.jpg

Kingpin

A lovely collection piece, and the chipped paint somehow makes it more appealing. :)

Mark

I was intending to do a refurbishment on the lamp to bring it back to its original looking condition complete with a brand new shiny coat of paint however since you've mentioned it, you've given my second thoughts Kingpin.

I do think you are right about how the chipped paint gives it an appealing sense, perhaps a glimpse back into its near 100 year life.

I think what I will do for now is carefully strip it down and give it a good clean - firstly as I would never get away with having it living in the house in that state, and mainly to make sure there is no underlaying rust etc that needs attention.

Also it will be easier to measure and document it in case no plans/drawings turn up.

TG

Would someone (possibly Mark?) be able to provide some dims?
1.Overall height of the lamp
2.Height and diameter of the gong
3.Height and diameter of the dome nut (is the nut hexagonal?)
4.Height of the mesh section
5.Detail measurement of a diamond in the mesh

They are fantastic pictures of your lamp Mark - thank you for posting them!

A rough line drawing of the lamp.
scottish_lamp-line.jpg

Mark

Hi TG,

Just posted on your other thread. I haven't forgotten about sorting measurements out for you, was busier than expected. I'll get them all sorted for this weekend for definite - I promise

Mark

May 30, 2019, 09:51 pm #9 Last Edit: May 30, 2019, 09:58 pm by Mark
Ok, so things didn't go quite to plan today as I had figured I would strip the lantern down to it's individual parts to make measurement taking easier however some bolts/screws were seized so for now I've been really liberal with the WD40.

All is not lost as I've taken some measurements of the brass top nuts to kick things off and the nut parts are indeed hexagonal.

One thing to note is that I've used mixed units as some things work out nicely in inches and others were easier to list in millimeters
IMG_20190530_223917.jpg
IMG_20190530_223737.jpg
IMG_20190530_224143.jpg
IMG_20190530_224120.jpg
IMG_20190530_224054.jpg
IMG_20190530_223944.jpg
IMG_20190530_224011.jpg
Since measuring, drawing up the plan and uploading the pictures I've realised I've missed a few measurements so I will sort those out tomorrow.

starcross

May 31, 2019, 12:47 am #10 Last Edit: May 31, 2019, 12:57 am by starcross
Quote from: Mark on May 11, 2019, 07:17 pm
I would guess that is the bracket a striking mechanism would attach to as it doesn't serve any other purpose.


Looking at the lantern markings the FHR6011 should be code for November 1960. Mine is marked to indicate January 1955. No idea if that is true or not without some research but its what I recall being correct.

The large Gap in the Avoncroft Lantern is due to it sitting on the Lock Nut. Notice that only the Dome Nut is the only one visible. Most pictures of these lanterns have the dome first, then the lock Nut, then the Dome nut covering that.

Also You are correct about the clapper position.  

This was given to me by a man named Rodney in 2013, it is inside his personal PA1 Pillar in his garden.
He was kind enough to sketch out the details of the clapper solenoid.
As far as I know this is the only clapper still inside one of these lamps.
By the time they make it to our hands they are quite empty or never had one fitted.

PA1 Bell clapper 1.JPG
PA1 Bell clapper 8.JPG

Mark

That's an awesome picture Starcross, thank you for sharing. It is the only image I've ever seen of the clapper/striking mechanism. I expected something like you see on old fire alarm gongs but this is so compact and simple.

Good news for tonight in so far as last night's WD40 soaking, and some more this morning before work, has made dismantling everything fairly pain free.
IMG_20190531_211505.jpg

I've given everything except the bulb holder a quick wash in soapy water and tomorrow I plan on getting some more measurements done for TG.

Here's a question for you all, I knew the hinge was broken when I bought it so does anyone have any clues how you might repair cast iron?

starcross

I'm quite envious that you managed to get the lantern completely disassembled.

My own example had screws that refused to budge the lower grill brackets, I could never get it off the base. I never tried really soaking completely as I don't want to destroy the nice deep red paint. Though I would like to sand blast and repaint the grill a proper black.

Any advice on how to loosen those screws?

warmcanofcoke

Jun 01, 2019, 02:01 am #13 Last Edit: Jun 01, 2019, 02:11 am by warmcanofcoke
DN6 .... WD40 : spray around where the nut comes in contact with the thread of the bolt. Then give it a little time to work itself in to the assemblage. There is both a cap nut and a lock nut. Try for the cap nut first. Because you probably don't want to strip the out side of the nut you may want to use a strip of fabric or even scrap craft leather between the teeth of the wrench/vice and the nut. And then perhaps elbow grease - take your time - it is not a race. Try to be mindful of how much force you are applying. If it desn't work right away apply a few extra squirts of WD40 and let it sink in overnight. Repeat.

If you can attach the base of the lamp to a board and weigh it down, it may help you get a handle on turning that nut.

Quotehttps://www.youtube.com/watch?time_continue=31&v=UrrLcONm2zk
why doesn't the Guide mention them? - Oh, it's not very accurate.
Oh? - I'm researching the new edition.

Mark

Well I was very lucky in the fact that the dome nut and the four flat headed screws which hold the lid to the grill had copper grease applied so they can out very easily.

The lower screws holding the grill to the base were a proper pain. I'm guessing the reason is two fold as they are exposed to the elements down there and because of the slope of the base which means the screw heads point towards the grill making it tricky to get a screwdriver lined up properly.

I applied WD40 from the top, aiming under the head of the screw and then after about an hour I tuned the lantern upside down and sprayed from underneath trying to get the spray penetrating from both ends of the bolt.

I left it for about 12 hours and then did the same in the morning. I've read on forums about car maintenance that some people have done this process for real stubborn jobs over the space of a week before the thing shifts.

As Nate said, applying downward pressure and turning slowly is the key, I've stripped so many heads by rushing. If you do get it to budge a little bit whack more WD40 down there and leave it to work.

In my experience of using WD40, I've never had a problem with it affecting paint and I don't think it acts like a paint stripper.

When I put it back together I shall definitely be using copper grease on all the fixtures to ease any future disassembly.