Monday, 23 February 2015

Keeping the Heat In (A Cover-Up!) (3)

February 23rd 2015 saw the integration of the side skirts with the boiler top cover. (Compare to this).
Boiler Top Cover with Sides fitted
There were still a few screws left to do after the above photo was taken but they are now in place and it all fits together (with a bit of persuasion)!

The next task is to take the complete top cover off again to allow space for other boiler top constructions. Firstly the superheater steady plates and secondly the vertical supports for the top cover.

Not obvious above is that the semi-circular cladding plates have also been fitted around the boiler top. Back in June 2011, they looked like this after their restoration but it has taken a long time to actually get them fitted.
Cladding Plates
Worthy of note is that they are fixed by screws into existing threaded holes in the circular angle iron girder around the top of the boiler side cladding plates. The stainless steel screws used were an odd thread for this situation in that they were 2BA (which cost a lot more than metric screws nowadays!). It is odd that Sentinel should have used a BA thread where all other screws were Whitworth.

Saturday, 14 February 2015

Sentinels 8398 & 8400 Retired

I was saddened to hear this week from my contact in Brazil that the two other remaining pre-war double-engined Sentinel locos ceased their long working career on October 31st 2014.
Sentinel 8398 at work at Amsted Maxion Steelworks in Cruzeiro on 2nd Mar 2012.
Photo James Waite.
Discussions are under way to put the two into preservation; however, I don't know how things are progressing. I hope to have more news in due course.
Sentinel 8400 at work at Amsted Maxion Steelworks in Cruzeiro on 2nd Mar 2012.
Photo James Waite.
These two locomotives were manufactured by Sentinel in their works at Shrewsbury in 1930. They are two of three originally delivered to the Sau Paulo Railway, Brazil; I believe attempts were made some years ago to convert 8399 to diesel but without success and the result was scrapped.


Tuesday, 3 February 2015

Unexpected Surprise

A very cold Monday 2nd Feb. started with an attempt to repaint the cab roof. The first problem was that the paint was so cold it had the consistency of Tar! Leaving the paint tin in hot water for a while turned its contents back to liquid.

Problem solved so I thought but only to be thwarted by 7109 being chilled to the core overnight in Midsomer Norton's goods shed. As soon as the paint touched the cold metal, it went back to tar and couldn't be spread. I gave up at this point.

Nigel (co-owner) appeared with two sheets of the cold steel to make a pair of superheater steady plates something like in the drawing below (apologies for the low resolution). These are screwed to the boiler top plate around the superheater tubes to eliminate leakage of air into the boiler's superheater space every time there is a 'chuff'. Each 'chuff' is supposed to draw air up through the fire not in via the leaks! I'll come back to this another time.
Superheater steady plate drawing
We had a visit from Mr S., an S&DRHT member whom I'd not met before. I showed him over 7109 in my usual manner. He remarked that he followed the blog and enjoyed seeing the progress. To my great surprise, he delved into his pocket and produced a modern version of the item below to make us a donation. This immediately paid for the just-purchased cold steel mentioned above!
Oldie but Goodie
Many thanks Mr S. May more visitors such as yourself please come and see us at work and be shown 7109's secrets! (If you can't visit in person, there's always this as an alternative!).

Work continued with attempting to persuade the boiler cover to fit. I have to admit that part way through the afternoon, I had to give up due to the cold. When the entire loco is freezing cold, every touch of the cold metal, whether it's feet or hands, loses a little more body heat. I'd run out!

Next Saturday 7th Feb. 2015 is the Sentinel Drivers Club AGM for the group of stalwarts who support all things Sentinel, including 7109.

Tuesday, 27 January 2015

Keeping the Heat In (A Cover-Up!) (2)

Monday 26th Jan. 2015 saw the first attempt at fitting the boiler top cover to the chimney assembly. An earlier article showed what the cover was like before work began on it.
Start of the Boiler Top Cover assembly
There is a rim around the base of the chimney heat shields that supports the centre of the top cover. The cover will then also be supported by six tall spacers sitting on the extended studs protruding from the boiler fixings (there's one just to the left of the LHS superheater tube in the foreground).
Space getting tighter
Having examined the boiler of the only other double engined Sentinel (9622) in the UK, I'm expecting the spacers to be 6.25". However, this is far from the case; they are sitting much higher and the LHS and RHS halves of the cover are not fitting very comfortably.


Some further investigation is needed.

Sunday, 25 January 2015

Getting on a Flap

Just to top-off the previous chimney article, the damper flaps have been added.
Ta Da! Flaps Open...
...Flaps Closed
And the remote controls:
Flap Open...
...Flap Closed (or was it the other way round?)
Still more to do with adding the Chimney Surround to the cab roof and the boiler top covers.

Damping down a fire for a short period can be done either by restricting air flow into or out of the fire (or both). Whilst some air-in damping can be done by adjusting Sentinel 7109's ash pan, Sentinel chose to restrict the air-out mainly by enabling flaps to be placed over the chimneys.
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