Petromax mantles

@Peter Perry the control wheel should turn smoothly in either direction so something is amiss.





As the control wheel is turned, the needle rod oscillates slightly. A long shot I know but if for some reason there's a burr on either of the edges of the slot, the oscillation may allow the wheel to be turned in one direction but not the other.

 

They aren't directionally dependant as far as I know so they should work the same both ways, but I've had one or two that act like yours does. You can fiddle with the height of the needle by taking the generator/ Preston loop off carefully. You'll then have the rod and the pricker needle sticking up so you need to be careful with the needle as it's very easy to knock by accident. Anyhow, the rod unscrews and has a tiny nut on it down the bottom. You can screw this up and down to change how high the needle goes. If you're careful you can experiment to find the correct height which should allow the control valve dick to go both ways but be very slow and careful when you slide the generator/loop back down over the pricker rod! Hope this helps.

 

Aha, Henry beat me too it... and with photos too!

 

Thanks Henry and Colin something else I've discovered with it but it's hard to describe.
Turning the wheel anti- clockwise is smooth until it gets to the point where it locks going clockwise then it goes slack then picks up again to complete its 360 .
Then Turning clockwise to that point it just locks so as you both said somethings amiss .
I'll strip it tonight and take a look why does work always get in the way.
Thanks guys

 

When it locks in both directions (or it is hard to get it past a certain position turning in both directions) then probably your needle adjustment is wrong and needs to be lowered. It pushes hard against the nipple. Of course, if this also happens when the nipple is out, ignore this! (you can check by gradually unscrewing the nipple till the point of no resistance then check how far the nipple is unscrewed to see how much the needle rod needs to be lowered).

 

@Wim
That's very clever wim I'll give that a go when I get a chance .
Not sure that's the case though as it only locks clockwise but not anti but worth a try thanks for that .

 

Once you have removed the upper part of the generator(Preston loop), try turning the pricker knob in all directions. It should move without much restrictions except slightly when the pricker rod is going against a spring-loaded footvalve inside the fount.
If its stuck at any point, then someone earlier might have assembled the pricker control stem wrongly. That would cause the stem-end to force against the eccentric block in an inppropriate way and creates resistance to movements. It can happen sometimes but you can easily correct it if that's the case.

 

Send a picture of the needle at its highest point, if it’s an adjustment it will be apparent.

 

@MYN thanks I've taken your advice on board ill keep you informed when I get chance to look at it.

 

@John that's how it is at the moment john before I dismantle the vapouriser to take a look .
Thanks

 

Hi guys after much teeth gnashing, shirt ripping and occasional blue words I've got the wheel to turn clockwise but I think I need a new one as the nipple seems worn but for now she turns smoothly with just a hint of needle through the jet .

 

Good work! How did you do it?

 

Hi Colin I applied gentle pressure to the middle rod then holding it down turned the centre wheel nut till it engaged.
Not the easiest thing to do took me ages as it kept slipping out as I turned the wheel then I had do do it all again after too much needle was showing .
Anyway hey its done and thanks for your contribution.

 

Whatever you've done, it works so far .
Make sure the pricker rod is screwed firmly with the tiny square locknut to prevent loosening. Otherwise, you'd have to dis-assemble them apart again and set the proper needle height again. Rather tedious sometimes.

 

These lamps are all about getting the adjustments right, after that they will definitely brighten up your night.

 

Hello again guys I've run into a slight problem I've fitted a new jet I received yesterday from base camp but the max I can get the gap between the jet and mixer tube is only 11.7mm have I missed something?.
Very reluctant to light before I get the gap to at least 14.2 mm.

 

How thick is the seal or seals under the vaporiser where you mount it to the tank?
I assume you looked at adjusting the position of the J-tube ?

 

Hi Pete, I've just seen your thread and yes something is definitely amiss as your jet is sitting too high in the frame, is it possible that the vapouriser unit is not screwed all the way into the fount, I've added a picture of what it should look from my own petromax

Hope this helps
Regards Ian

 

@Mr cod thanks for that Ian after strip down number 342 I've been able to turn the gen another couple of times now it's really really tight so glad you put me onto it .

 

@WimVe
I am such an idiot I've tightened the gen up more regards to Ian for that then your suggestion about the mixer tube sorted it .
I loosened the ceramic holder and was able to gain the distance required then tightened up.
Thanks guys your awesome.

 

Well she's one sexy lady now guys and roaring away for the past hour so from the skip to glory.
I'm still not convinced though about the generator the wheel has begun to lock again one way and leaking fuel from the jet when in the upright position so I guess its back to the drawing board but for now I'm just enjoying its light.
Thanks to all you guys who have helped much appreciated.

 

Well the only tricky part of the whole design is the rod operating the cleaning needle and the foot valve at the same time. So you have to adjust and secure both ends correctly.
If under pressure and valve not completely shut it will leak since there is no shut off at the top end.
Remember that the needle is only for cleaning not closing or even adjusting the light output.

 

@WimVe Yes I understand the mechanics of it as in how it works and why I just don't know now how to improve its function it has a new nrv valve and that's not adjustable from what I see though I could be wrong so it's scratch my head time .
Thanks for the help

 

The valve is not adjustable the push rod is.
If the distance for the cleaning needle is just correct it may be so that due to expansion by heat it just doesn't fit any more hence the blockage of not turning freely.

 

@WimVe
Oooooooooh you may be onto something there but you'll have to indulge me I don't quite get what you mean exactly are you saying the push rod is worn or the generator walls are worn I mean it is a sixty year old lamp.

 

No I think I didn't make it clear enough:
the extender on the main "hand wheel" operates the extender block. Well shown by @Henry Plews.
on this block there are two rods, one for the main valve and one going up for the cleaning needle. BOTH have to be correctly adjusted in length. The lower one most of the time is the correct length once in place but should be checked.

How ? by operating the hand wheel without the jet mounted. The movement must be without any bumps or blockages. The only resistant is that of the spring loaded bottom main valve.

If that is ok, place the jet firmly and operate again. This should also be without any problems. If so you need to lower/shorten the upper needle rod. It should be so long that the tip of the needle just comes out of the jet (1-2mm). Off coarse the needle must be al the way down fixed on the rod.

All of this can be done without the rest of the lantern mounted.

I hope this makes it all clear and understandable.
Turning the hand wheel around must be without any obstruction.

 

@WimVe
Thanks for writing all of that I appreciate your explanation its much more clear.
I think the pricker needle may be showing out of the jet a bit too much so will need adjustment I just can't see how this would affect the foot valve and stop the locking but I'm no expert.
Thanks for your time.

 

I can see your attraction to these lamps she is beautiful and definitely a keeper

 

That looks to be running very well, I find a great sense of satisfaction when a successful outcome is achieved.
Ian