Mallard

[cabbage]

Ok here is where everyone breaks down in laughter... Yes the fanatic about traction has bought himself a steam locomotive.

It will be delivered next Wednesday.

However I will need to know the thread of the safety valves and the gas tank valve.

This will be needed to make adaptors and blanking plugs to ME 1/4x40tpi plumbing of the test equipment... I am assuming that it is a metric thread of some kind(?)

Regards

Ralph

[AshleyW]

i've asked mike about the 14xx threads and was told 04.5mm x1mm but some were 5mm, so best check, there's a faq and contact to mike via the kingscale pages.
some loco's you cannot get a box spanner over the safety valve due to the casing/roof. some members have removed the inners instead and blanked off inside the safety valve itself.

[IanT]

Yes Ralph, off the top of my head, it's 4.5mm - an odd size die that I didn't have.

Roy had already purchased a 4.5mm one though and I borrowed it to to make a couple of 'extended' adaptors (to 1/4"/40). He advised making them longer 'reach' to get through the cladding but I cann't access the exact detail at the moment as I'm on my 'new' laptop.

Best idea would be to talk to Roy I think.

Regards,

IanT

[cabbage]

Roy has confirmed the thread as

Metric Fine 5.0 x 0.5mm

Currently I am hunting through the scrap draws for a length of 1/4" and 5mm brass rod....

Regards

Ralph

[AshleyW]

will look forward to seeing that in action. ash

[cabbage]

Well it arrives at 8am this morning and the van had to make three attempts to get up the hill... A -6°C box of Mallard spent an hour on the kitchen table defrosting.

It is massive! Even with the number of G3 models rhat I have built the only thing that comes near to it is the class 45 Peak.

One of the things that puzzles me is the gas jet. There seems to be no method of retaining it other than just sticking it in the hole(?)

It will be the new year before I can get it running but in the meantime I keep looking at it and going OMG!!!

regards

Ralph

[cabbage]

Well I have done a couple of things to it that make things more "obvious" . I have snapped cable markers around the three rubber tubes from the tender. Red for gas, Blue for pump and White for return. There are matching "stars" on the rear of the loco. Unlike the crew updating the EP-2 I will not allow a label saying "we don't lnow where these go?"

I am still not happy about the gas jet "simply being there" I have not decided if a velcro grab patch or a magnet strap would be the better solution (?)

Regards

Ralph

[AshleyW]

a fag paper around the gas jet holder, would make it very snug into the loco orifice.

[cabbage]

Well last Saturday was the steam test day, after some fiddling with homemade adaptors (thank you Andrew), we placed it on "the dragstrip" and it puffed up and down.

But, the steam raising ability was not that high...

We examined the gas jet and found it to have a microscopic nozzle. We swapped out the jet from my 14xx which had a larger and visible hole and Mallard awoke!!!

I don't know what size gas jet was fitted other than too small. Neither the one from the 14xx or Mallard have any size numbers stamped on them. I am used to the jet numbers used by Roundhouse and Accucraft.

The thread used by the jets is MF5.0x0.5mm

So - anyone any ideas?

Regards

Ralph

[cabbage]

Having gone through some maths (with some very hairy assumptions!) I arrive with a nozzle size of 0.22mm. This is (I think) slightly small but is a good fit for #8 at 0.25mm.

The next size up #10 is 0.277mm and #12 is 0.3mm.

A #12 is probably the one for this size of loco as #10 is a common G1 Accucraft size.

Regards

Ralph

[AshleyW]

it could  also be crap from the gas or residue from the build in the tank.pipes of the tender. perhaps swapping the jet let some residue flow out. we often find some warmed water (into a tender with some cold water in already - not direct to gas tank) will really give the fire a boost . usually blowing gas down the said jet will clear any debris.

[cabbage]

Ashley, of you have a look at the jpg below then you will see the original jet on the right. The jet from the 14xx is on the left and has a bore less than 1.0mm

Regards

Ralph

[AshleyW]

but perhaps the 14xx has thinner bore as it's gas supply is direct from loco and via plumbed pipework, where as the tender loco has flexible tubing and further to travel, so may be designed that way. my experience with all the kingscales are that the jets get blocked (poss every 3-4 runs) and frequently need cleaning out with the gas .

[hornbeam]

Interesting Ashley, glad I'm not alone with the blocked jet issue. Having owned many Roundhouse engineering live steam locos in the past and using the same good quality gas I never experienced blocking of jets like I do on my 14xx. It's very annoying!

[cabbage]

Ashley, the 14xx (L)1 has the LARGER bore than the Mallard (R). The 14xx jet bore is between 0.5 and 1.0mm

The one on the Mallard is smaller than a #32 hypodermic syringe needle!!!

After e-mails with Kingscale it seems that that tiny jet is correct(?) But they are going to ship me a 14xx jet.

Regards

Ralph