Thursday, 24 January 2013

Boiler Fittings (2)

At the end of my last article on attempting to fit the first of the boiler fittings, I'd found that the protruding screws for the boiler fittings were not parallel but pointing out radially from the centre line of the cylindrical boiler.

Faced with the problem of how to make the screws parallel, I took advice from our boiler maker Mendip Steam Restorations.

The important point is to understand how the screws are fitted to the boiler so as not to risk damaging them during the 'parallelising' process. The screws are not engineering studs as I'd thought but high-tensile screws fitted from the inside and sealed using a copper washer. Thus heat should be avoided as it could disturb the seal and any percussive (hammering) approach would not be sensible either.

I was advised that I should use a piece of pipe which would fit over the screw threads so that I could bend the screws cold with the extra leverage. Care to avoid damaging the threads would be needed also.

I settled on the idea of a 1" inside diameter piece of pipe of length 11.25"; this was the maximum length that could be fitted between the boiler and the front of the cab. It would also fit nicely over the 1/2" Whitworth nuts so I thought. Of course plans had to be changed when I found that the screws were 5/8" and the nuts would not fit into the pipe. It's a voyage of discovery with this mistress!

So two larger 5/8" nuts were reduced by angle grinder to fit the pipe as well as the thread. And here they are:
Reduced pair of nuts on the lower left screw
(One nut is close to the boiler shell to avoid bending
the screw near the shell and weakening the seal).
Before attempting the tweak on the front of the boiler where space is restricted, I thought I'd just have a quick go on a more accessible one at the rear (which will eventually support the regulator assembly).

Now I'm not particularly strong but not that weak either but attempting to bend a 5/8" high-tensile Whitworth screw with only 11.25" of leverage was way beyond me (particularly as fine adjustment was needed). So a longer pipe was going to be needed and not a straight one!

And here it is:
A nice fit
And the length?
About 4 feet of leverage
How wide is the cab, I hear you ask? Not wide enough!
New use for the off-side window!
As you can see, the window aperture has found an additional use!

Now I've been able to begin the adjustments but, as luck would have it, a horizontal adjustment is not quite all that is needed. Some vertical adjustment is also needed. So the pipe extension is going to need curtailing.

Nearly there but not quite. At least I now know how to do the parallelising!

Monday, 21 January 2013

Cab Windows 'Radstock Style'

After 2012's so-called summer and the recent snow, I've been getting rather depressed about the amount of water lying around the cab every time I visit Sentinel 7109 for a site work-day. So I turned to a Radstock Sentinel style makeover to solve the problem.
Normality to date - Air-vent style 'Spectacle' Windows
(Refer to the heading photo if the window is not clear here!)
I've had no response to my plea for replacement windows so until now, fresh air and the ingress of the elements has been the rule of the day. After a little lateral (or perhaps vertical?) thinking, I decided that the windows would have to be square after all - just like the Radstock Sentinels. So here they are:
Cab Front view
Cab Rear View
However, for those of you who know me, you may recall that I've said that, as a principle, I would never do this as it would spoil a piece of industrial archaeology such that Sentinel 7109 would neither be itself nor a Radstock Sentinel.
So have I flipped? No, not this time.
Fire-glow from the window
The silhouetted spectacle opening still shows behind the gaffer-tape framed polythene sheet window squares. Cheap and cheerful!

Tuesday, 8 January 2013

Boiler Fittings (1)

Remember this item from a previous article?
Superheater feed manifold
What about this one? Possibly a more recognisable item depending on how well you've been following my 'blog exploits in the past.
Regulator Assembly in place (before restoration in December 2004)
The first is the four-way manifold used to feed the boiler's wet steam output to the four-ring superheater input; the second is the regulator assembly which receives the output from the superheater.

I showed the fitting of the superheater in a previous article confidently assuming that it could stay put from then on as in the photo below.
Superheater assembly neatly sitting in the top of the boiler
How naive!

What I hadn't spotted was that, with 2" studs sticking upwards from the manifold and regulator assembly, there was no way that these could be fitted on to the horizontal studs on the boiler without lifting the superheater about 3".

The only lifting gear at Midsomer Norton is a road-railer but it has not been available for some time. So ingenuity was going to be required.
Temporary Aerial convergent 'plate-way' in use!
I knew I could lay my hands on a jack and a lorry strap and that the superheater weighed about a quarter of a ton. After a few checks, I found my trolley jack was rated at 1.8 tons and the lorry strap at 3 tons so all was well within safe limits.

So it was a simple matter of putting the plate-way (point rods) in place to support the jack, tighten the straps and jack up the superheater. It worked like a dream!
Precise lifting ability
The jack is ideal for this as it can lift the superheater precisely to the right height and then lower it on to wooden beams for longer term support. Not wise to depend on the strap (particularly as it would get in the way of keeping out the rain!).
Interim resting place
Superheater rings showing below the top plate
So far, so good I thought until I tried to fit the manifold.

When the boiler was refurbished, all the studs were renewed. Of course, the new studs protrude precisely at right angles to the curved surface of the boiler - which means that they are not parallel! They are further apart at their outer ends than at the boiler surface and hence wouldn't mate with the holes in the manifold flange.
Five brand new studs for the manifold fixing
(there is a blanking plate fitted in the photo for a hydraulic test - I guess it had bigger holes!)
I've got a few options: bash it hard enough to make it fit (don't like that); grind the edges or ends of the studs or bend the studs so they are parallel (maybe); drill out the holes in the manifold flange (not keen on that). I'm still thinking about this!

More to come when the bits are in place.

Saturday, 5 January 2013

Sentinel 8398

Pre-delivery Works photo of Sentinel 8398
(Source: Sentinel Patent Locomotives 1931)
Following on from some brief correspondence between the Sentinel Drivers' Club and International Steam's James Waite, I've found some more video and pictures of Sentinel 7109's younger sibling in Brazil in 2009.

Courtesy of Andreas Illert and International Steam, I've appended the various links in Remaining double-engined Sentinel locomotives.
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