Thursday 23 April 2015

Maintenance Update (lap, face, shiny, fixed)

Friday 17th
Clive reports:
" Regarding the 'hot' pony, neither my driver, Sean Nielsen, or myself noticed any excess heat in that area apart from normal running. Reckon **** has been doing too much washing up without his Marigolds."
{So, I'll write that issue off as investigated + no problem found}

Bruce reports about the clack problem:
"Something wrong here, on Wed we went to quite a lot of trouble to clean the faces and align them properly when clamping them up. What are we doing wrong?"

My theory.
"Let's assume that if both faces are flat, so that when they are clamped up, a THIN gasket should seal ok.  But, as the clamping bolts are outside the raised sealing area it is easy to clamp the faces slightly out of parallel, so, if a thin gasket is used it may not be able to cope with this variation.  Would it be better to use a thicker reinforced gasket to take up any misalignment better?  I acknowledge that a thin gasket is best if you can get it to seal.  Is this valid or am I completely barking up the wrong tree?"

Saturday 18th
David, Bruce and Gilbert spent the whole day working on the leaky clack box joint. Once the clack box was off, Bruce set to, lapping the face to make sure it was perfectly flat.  He found some thicker gasket material and cut a new gasket for it.

Meanwhile, Carpo had looked at the studs that held the clack box to the valve assembly, and decided that the studs were life-expired.  So, David & Gil began removing them.  The usual way is to fit two nuts on the end, tighten them really hard and then undo the pair - usually they grip the threads hard enough to be able to turn the stud and remove it.  This worked on four of the five studs!  After struggling for ages, David decided to weld a nut on the end of the stud and try to turn it that way.  The first attempt ended in the weld breaking before the stud would turn!  So David applied even more weld, and then  finally managed to turn the stud and get it out.

Thereafter, the three of them took it in turns to lap that face.  It's a strain on the arms, because you are moving the lapping block in a vertical plane all of the time.

Carpo made a set of new studs for us {Thank you, Ian!}.  I found some fresh nuts to fit, plus new spring washers.

In a spare moment, Bruce thought to check the nuts on the new blow-down valve, to ensure they were tight after the first few steamings.  They were.

More in hope than expectation, I cleaned the firebox grate and laid a warming fire … but didn't light it!

By end of day, the decision was not to rush things, but complete the job carefully on Wednesday.

Monday 20th
Bruce reported
"This morning David brought his large file to remove material from the Clack Box sealing face to improve the flatness.  We both spent the next couple of hours removing material from the face, but not enough to clean it up.  David then had to leave.

I went back this afternoon and carried on filing, hoping to clean it up, but the flange is so large that I could not remove enough to get rid of the low area completely, but it was getting close.

I then tried lapping the face to get rid of the filing marks and flatten it off and give a better idea how much more needed to be removed.

After several lapping cycles the face had cleaned up except for the low area at the bottom which had only cleaned up across about half its width.

I measured the gap on the bit that had not cleaned up with feeler gauges and found that the largest gap was only 0.003"

In consultation with Carpo I explained that it would probably take at least another half day to clean up the last bit of face completely, so he agreed that it was good enough to reassemble it and see what happens, particularly as we need to be available for the wartime event at the weekend.

It was 5.15pm by the time I had finished so I did not clean the flange.  

Before inserting the studs the threaded holes need cleaning out."

Wednesday 22nd
Jamie & Chris B7 [Loco Dept] took the leaky J-cock off the side of the smokebox and hence found out how it fits!  They gave it a good clean; obtained a new copper washer (from Dinmore Manor group) and reassembled it.  Jamie confirmed that there was oil in the pipe, so that means it is working!

Bruce & Gilbert spent nearly all day working on the clack valve.  The new studs were fitted, but then they didn't quite fit the holes in the clack!  So, Bruce had to tease a couple of holes open a tad.  When it did fit, they verified that nothing was fouling the clack valve and that the two surfaces were absolutely flat against each other.  Bruce also ground a little bit off the clack body to make sure that the nuts & spring washers fitted flush.  The new gasket is thicker and also reinforced.  Carpo kept an eye on things and gave the "all clear" to light a warming fire, which John G and I then did.

Apart from this, Bruce checked the balance weights in the wheels.  John polished everything brass and copper in the cab (to impress the folks on the Fire & Drive on Friday!).  Chris and I lifted the brass bonnet onto the firebox top in anticipation of fitting it after steam test on Thursday.

I had cleaned up four rail chairs during the day, and John painted their bottoms.

Fred was assisted by Geof and Bill at Winchcombe, working on the siphon restoration.

Thursday 23rd
I got to Todders at 10 am.  There were still embers from last night's warming fire, so a quick rake round of the ash, plus a few shovels of coal and I got the fire going again.  However, there was no pressure, and with only half of the grate covered you can't use the blower, so it was after lunch by the time I'd got 30 psi.  Carpo decided to test the injector at that, and there was no sign of a leak.  Then he told me to spread the fire; make a full-grate fire and raise pressure.  By 3 o'clock I'd got 200 psi.  Carpo observed the clack as I injected, and he declared it "passed".

Having got her hot, but going nowhere, she continued to blow off until 4.30 despite periodic injections to cool her down a bit.  Anyway, I fitted the cover over the delivery pipe (to the clack) and then fitted the brass bonnet over the valves.  It was bloomin' hot up there - sun as well as boiler!  I thought my overalls were melting at one point!

I left at 5pm with 180 on the clock; had a take-away; returned at 7pm at which point she had 140 psi.  Checked round; put the chimney cap on; shut the gauge frame; shut the fire hole doors and finally … I'm home!


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