Acetylene Lighting - Burner threads?

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jessplop
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Re: Acetylene Lighting - Burner threads?

Unread post by jessplop » Thu Jun 04, 2009 2:46 pm

They utilise a metal to metal seal on the shoulder (up to 7,000 psi), the internal diameter is maintained as a constant to reduce pressure loss due to friction, and the pipe must also be able to hold the weight of the drill string, so the connections have a "tool joint" section which has a larger diameter that the nominal size of the pipe. As, for example, 5" drill pipe weighs 19-1/2 lbs/ft, and a drill string can be anything upto 30,000 feet in length, plus the weight of a bottom hole assembly (itself weighing upto 40 tons or more), you can imagine the loading on the threads (make up torque of 5" drill pipe in the region of 19,000 ft/lbs, 9-1/2" drill collars 90,000 ft/lbs). In addition to all this, drilling torque, vibration, bending moments (whilst drilling deviated holes), jarring to free stuck pipe and, of course, the numpty drillers who don't quite understand physics. Drill pipe has a tough life!

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Justin Faithfull
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Re: Acetylene Lighting - Burner threads?

Unread post by Justin Faithfull » Thu Jun 04, 2009 11:48 pm

News update (or non update depending on how you look at it). I sent an e-mail to Conex (Frank's link), but they are unable to help - other than to say that it may be a non standard thread :lol:
And now it is confession time. Why did I ask this question in the first place? Well I had an idea ;)
I thought how about making an LED fitting that could simply be screwed into the place where the burner normally goes in the lamp (e.g. a burner fitting modified perhaps), then suitably adjusted in relation to the reflector (not necessary for rear lamp) for a 'good beam'. Wiring could run through the gas tubing & batteries fitted into acetylene generator body. Completely hidden & at the flick of a switch lights that you can use in the dark on an old bike that originally had gas lighting - originality left pretty much intact. :idea:
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Hooli
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Re: Acetylene Lighting - Burner threads?

Unread post by Hooli » Thu Jun 04, 2009 11:50 pm

sounds like your going to have to butcher a wick holder to attempt that then.
Classics ain't built in Metric

The Mighty Gusset

Re: Acetylene Lighting - Burner threads?

Unread post by The Mighty Gusset » Fri Jun 05, 2009 12:26 am

Justin Faithfull wrote: I thought how about making an LED fitting that could simply be screwed into the place where the burner normally goes in the lamp (e.g. a burner fitting modified perhaps), then suitably adjusted in relation to the reflector (not necessary for rear lamp) for a 'good beam'.
Hmmm !
The problem with that idea is that LED's are very 'directional' - not as bad as they used to be - but you do have to be looking pretty much straight at them.
Which does tend to render a reflector pretty useless.
I see what you are getting at though.
I'm not sure how you could make it though.

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Greenbat
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Re: Acetylene Lighting - Burner threads?

Unread post by Greenbat » Fri Jun 05, 2009 12:34 am

Hooli wrote:sounds like your going to have to butcher a wick holder to attempt that then.
Not necessarily. Get on down your local CNC turner and have some taper threaded blanks made up :)




...I think there is a flaw somewhere in that one...
Tell you what-can you measure it up and knock up a drawing? I particularly need the thread dimensions-taper angle, pitch, thread depth and thread angle. There is a very, very slim chance I can help.

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Justin Faithfull
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Re: Acetylene Lighting - Burner threads?

Unread post by Justin Faithfull » Wed Jun 10, 2009 7:28 pm

Thank for you offer Greenbat, but making a holder is probably not a problem at the moment (it maybe when the time comes).
I am still researching, so things may go quiet from me in this thread, but I will come back to it & let you all know how I get on - assuming I do. :|
I have also tried my thread gauge on the threads & they seem to be about 26TPI. British Standard Cycle Taper perhaps :lol:
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Rick Parkington
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Re: Acetylene Lighting - Burner threads?

Unread post by Rick Parkington » Mon Jun 15, 2009 11:53 am

This is something of an oddity isn't it. I had a look in my 1935 East London Rubber Co catalogue (leave it!) hoping it might supply some description of the tpaered thread but it doesn't. It appears that Lucas didn't use it but several others did. Rather than being a given thread it could just be an in-house thing used by the manufacturer. It would be a pisser to go back in time and ask at a bike shop only to be told "Yerss, mate, course I knows it, that's P'n'H 'eadlight burner thread that is."
The LED question is also interesting. What Gus says about LEDs is quite correct but then you are replacing a flame not a bulb and the adjustable mirror inside the lamp may make that work well. My solution was to cut down a Lucas 7 inch reflector until it was a suitable diameter to fit into an old Powell and Hanmer shell. Clever old me...until I tried to fit the bulb and found that because the reflector depth was also now much shallower the bulb hit the glass. Doh!
Had to bodge the socket to take a stop tail bulb instead...
R

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Justin Faithfull
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Re: Acetylene Lighting - Burner threads?

Unread post by Justin Faithfull » Wed Jun 17, 2009 11:23 pm

My current thinking at the moment is to make screw in holder/adaptor to fit where the burner went. Make a push in fitting with the LED(s), to fit into this holder/adaptor (push in to allow it to be positioned in relation to the holder/adaptor). The LED(s) would not be upright, but would be horizontal, & would be pointed backwards towards the refelctor.
The above of course is only a tentative first idea I really need to see how much space I have to play with. Then there will be a need to focus the LED(s) in relation to the reflector - this would proably vary on different lamps. Rear & sidecar lamps should be much easier.
Anyway we'll see how I get on.
Elephants! Where?

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Justin Faithfull
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Re: Acetylene Lighting - Burner threads?

Unread post by Justin Faithfull » Mon Jun 22, 2009 8:52 pm

I finally have an answer concerning the tapered thread, I do not know if it is correct, but it sounds good & comes from a reputable source - John Diamond VMCC member & former Raleigh marque specialist for the vintage club.
I spoke to him at the Banbury run yesterday & he told me the taper is to allow the burner(s) to screw into a range of different size holders in different makes & models of lamps. In other words a sort of universal size of screw thread capable of fitting holders of a diameter at the smaller end of the taper all the way up to holders of a diameter at the larger end of the taper. I had wondered about gas leakage, but as the pressure is very low & there should be no resistance to flow so I can't see this as a problem.
Any thoughts?
Elephants! Where?

The Mighty Gusset

Re: Acetylene Lighting - Burner threads?

Unread post by The Mighty Gusset » Mon Jun 22, 2009 9:01 pm

That almost makes some sort of sense !

I did wonder, as a tapered thread, especially at that sort of angle, is only going to work over a very small number of threads, having it as a sort of universal, fits sodding anything fitting would seem to be a solution of sorts.

Not as good as having a standardised thread of course, but that's a relatively new-fangled concept.

Thanks for the entertainment !

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