Hi,
As some may probably know,the insulating triangle on early wartime horns apart from part number and date were marked 100 PHONS. Phons is a unit of loundness that for some reason was no longer being printed at some stage after March 1941 (the latest one i have is dated 3 41). According to Taff the Horns, Lucas started rating their horns in Decibels instead of Phons sometime after this date but they didn't print the result on the insulating plate. it may be possible, that in the 50s it was re-introduced.
What I am after is some help, that might help me narrow the date when the Phon script was deleted. Anyone willing to check his horns?

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Apologies, the latest one i got is dated September 1941!

Thanks Clive, Never to old to learn it seems. All horns I own have badly damaged triangles so not much info on them any more.

Henk

email (option): ahum@quicknet.nl

not many seem to care unfortunately

Clive, you've taken rivet-counting to new heights !

Respect !

I am not worthy !

email (option): 79x100@gmail.com

Its Taff not me......

I've just dismantled a fully functioning motorcycle to photograph this !

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August 1939 doesn't add any new information, I'm afraid (although pleased as otherwise I'd have an out-of-period plate !

Is my plate, with part no. 701405 originally from an HF1140 ? Henk's horn page might suggest this.

email (option): 79x100@gmail.com

Clive, here is one from a less common HF1346 for November '41 - that is missing that information.

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email (option): rays54@hotmail.com

Rik & Ray,

Thanks for the pictures!

Rik, so far I can't find any information to tell you what the part number means but HF1235 means; 'a cast iron bodied Altette with a non chromed (and unbranded) bezel' and with that date there isn't much more were to go. The cast iron Altette bodies were produced from 1937 after all. Possibly its a part number for a different finishing being that early? Maybe painted in some harder then usual 'crinkle' finish paint that was omitted in the early years of the war? for sure, at some later stage horns were leaving the Lucas factory unfinished, just painted with red undercoat.

Ray, although your picture is not from an HF1235 it is still significant. it has narrowed the change period by a mere 4 months. as i wrote yesterday, the latest Phons one I have (and i have so far seen) is dated from August 1941 while yours dates from November!

thanks again for the feedback.

Clive, the part number shown on the plates that you have posted - 701418 - seems to be the part number for a complete horn and by mid-1940, replacement parts for HF1235s were no longer supplied to workshops.

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For the earlier HF935, the VAOS doesn't list a number for a complete unit, only the components, making it almost impossible to compare.

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email (option): 79x100@gmail.com

No luck Rik....
not even Taff can explain this. he speculates it might be some supersession difference. he says lucas use hundred of different part numbers and many for the same items. in any case, i still say it might be something that had to do with finish. i have different part numbers for Austin Utility which are basically the same part but painted differently.

Curiosity got the best of me so I checked mine. My lettering looks stamped like Ray's but with 11 43 instead of 11 41 and it has HF 1235 701418 on the top. My bike is a 1943 WDM20. I did not know how to load a picture.

For good measure here's a '44 dated one:



Cheers,

Lex

email (option): welbike@wel***.net