Hello guys, I Just got this little friend from my Argentinian neighbours. Bottom marking 9 4, Argentinian Coleman glass slightly cracked, but it might work. I have some questions. 1. I found a 500 cp jet screwed in. Not tighted, I could remove it with my fingers. Is it posible to use the same carburator and a 100 cp reproduction? 2. Will you recommend me to replace jet, needle and carburator in 150cp? 3. Can anyone i.d if the needle attached in the picture is a 100c.p ? Any info is useful. Adolfo
You are fortunate to have found the Petromax 900 in your location. I guess they're mostly found in South America. 1. The orifice of a 500cp jet is too large for the Little Baby to handle. It should be 100cp. The 500cp jet has a different thread from the original 100cp jet. The threads of that carburetor/vaporizer would likely had been deformed by screwing in a 500cp jet. You should either repair it or find a suitable replacement that could fit a 100cp jet. 2. No recommendations but it could be done and would likely work as well. 3. Can't tell from the picture. You can measure its diametre with a vernier caliper or micrometer. Should be around ~0.12mm.
Thanks MYN and Jeff, Do you Know if I can find how to fix those 100 cp threads in this forum? Tips and tools.
@Adolfo , nice lantern @Tony Press has the same problem discussed here Petromax nipple thread questions You could braze the threads then cut a new thread. You would have to be careful not to melt the braze on the Preston loop.
Hello, nice lamp! The nozzles all have the thread M7 (7mm Dia. and metric thread). Just put a 100 or 150 cp (whatever you can find) in the vaporizer. The diameter of the nozzle @MYN mentioned (0,12mm) is right i think.
That's definitely not true! Please look at this image posted by Reinhard: Petromax nipple thread questions Screwing in a 150(new), 200(old), 250(new), 300(old), 350(new) or 500(old/new) HK size jet with M7 x 0.75 metric thread would deform the special thread of the old 100 HK vaporizers.
Ohh I see, than sorry for the wrong information. Didn‘t know, that there were different threads. Even the old hanging lamps from petromax (834 / 835 with steel nozzles) have „normal“ M7x1 threads.
No worries Marc, I sweat bullets when I see that tiny carburetor & threads. I Know some of you are totally skilful when fletting. In the meantime, I'm collecting as much info as I can. Ideally "measure twice, cut once". Thank you all lads for your replies.
I already ordered some new & jet reproductions from a Southkorean dealer. I will check if the threads is not seriously damaged.
I understand from your words that only an original jet might fit better into the carburetor, not a reproduction?, is that what you mean?
Firstly, you need to check the existing carburetor/vaporizer. I suppose you had found a 500cp jet being fitted in earlier? And you had no difficulties tightening and loosening it with your fingers? Then you should also double check the thread size and pitch of that particular jet with a thread gauge and a vernier caliper. If it is a standard 7 x 1,0mm or 7 x 0,75mm, then the threads of that carburetor are probably already deformed and would no longer properly fit an original Petromax 100cp jet.
from left to right 200 HK iron without marking fom My 834 Petromax Klaebisch pre-war 500 HK pre-war Petromax E&G 500 HK post-war Pelam-Petromax 100 HK pre-war PX marked from a little Baby 900 E&G
Taking the pixels in that photograph the pitch of the 100HK nipple is 0.75mm not 1mm. M7x0.75 is a known thread. Taps for cleaning up any mangling might work?
M7 x 0,75mm taps and dies should not be too hard to come by. It is Standard ISO Metric size(DIN13-4); fine thread. I'd certainly get a set of those. For repairs, I don't know how well would one of such thread restoring/repair files work on the damaged part?: I'd just silbraze to fill the vaporizer end and then re-thread it with an M7 x 0.75mm tap, preferably on a lathe to ensure straightness and concentricity.
Very interesting! I will try to contact a lathe operator. Machining is not my field though I can learn. How would define silbraze (verb)?
I am not sure but I guess that the Px900 was not designed in times that ISO-metric system was used in Germany. I guess (again) that early lamps manufactures used gas thread.
that's totally hairy. I wrote to machiningdoctor.com in order to learn more. Any other info related to the threads is indeed very useful before attempting some fettle.
I don't know how much similarity there is between Optimus and Petromax jets, but I have a very poor copy of an official Optimus drawing that states the thread for the 100 jet is 7 x 0.75. On the other hand, a drawing for all the other size jets states the thread as 7 mm diameter but the thread is 24 tpi Whittworth. Not the same as 7 x 1.0.
