Draw-bar Recovery (2a)

All that considering at the end of my last draw-bar cover article has bounced me into action with the Tiggling Stick to add a reinforcement angle iron to the draw-bar cover plate underside.

Angle iron reinforcement
(Should bear the weight of two separate Gorillas!)

Now it can be painted without it all being burnt-off again by the welding!

Draw-bar Recovery (2)

In the last article dealing with the water ingress and carp-related damage to the rear draw-bar's cushion cavity, I got as far as getting some paint slapped on to protect it from further corrosion. Now I had to get to grips again with the steel plate rolling machine that I'd used on the ashpan walls.

This time, I did remember to use my camera a little more effectively!

The old cover plate measured 33 inches long and 11.5 inches wide. As continual footfalls had dented it, this time the plate was going to be thicker at 2mm (which is about 2/3 of an 1/8th of an inch!) and will possibly have some angle bracket welded underneath to make it even stronger. K M Steel Fabrications Ltd of Haydon, Radstock kindly supplied the sheet steel and cut it to size.

The rolling machine with sheet inserted ready to roll!

Great care has to be taken to ensure that the sheet enters the rollers at right angles to avoid a twist which would make the sheet unusable. There is no photo evidence of my accurate tri-square used to set the sheet in place (I haven't got enough hands to hold a square, move a metal sheet and use a camera simultaneously even with a tripod!). It pays to take one's time to set things up accurately to avoid regretting it later.

Lines were drawn for the folds and the start and finish of the curvature

I had a problem in that I could not see my lines for the start and finish of the curve as they had to be trapped at the rollers' pinch point.

By moving the start of curve line to be directly below the right side of the roller and making a mark directly below the left side of the roller, I could then make the 'HERE' mark half-way between the two roller side lines. Thus, putting the 'HERE' line to the left of the roller then made sure the line for the start of the curve was at the pinch point of the rollers. Same for the end of curve line only the other way round.

Put the 'HERE' line to the left of the roller...

...then raise the rear roller and wind the sheet through...

...then a bit more...

...until finally!

Ok, so I went a bit too far and had to do some unbending which is not as easy as it seems; it's supposed to be a smooth curve, not one with a gradual curve in places and something tighter in others. Again some patient, manual adjustment got it there in the end.

This is how it happens in practice (also on YouTube).

A flange was then required at each end of the sheet for the mounting holes. This was the first time I'd used a sheet metal bending machine since about 1972 but it wasn't difficult.

Sheet metal bending machine

The lever without the counter-weight raises and lowers the clamping mechanism that hold the sheet in place. The lever with the counter-weight does the work.

So, having clamped the sheet in place at right angles to where you want the bend, it's simply a matter of raising the handle at the front like this (also on YouTube):

Note that, owing to only having two hands, the plate was already bent and the video is for illustrative purposes only!

And the final result:

The new cover plate with template; the old cover plate is above!

Now just some paint, drill a few holes, fix it in place and try standing on it. Then consider welding an angle iron reinforcement below the top for strength (and preferably before painting it!).

My thanks are due to Lackham College, Lacock, Wiltshire, for letting me skive-off my Monday evening welding class to do metal forming instead. It's all part of the fabrication process, honest!

Draw-bar Recovery (1)

Sentinel 7109's cab is cramped at the best of times. When the regulator assembly is eventually mounted on the rear of the boiler, cramped will be an understatement particularly when trying to get from one side of the cab to the other. Adding to the obstacle course is an odd shaped bulge by the floor below where the regulator will be.

Bulge - can be a battle when crossing!

If you click the image, you'll see that it has suffered many footfalls in time and is badly rusted near the foot plate floor. A stronger replacement cover plate will be made in due course.

So what is it that is so important to be given pride of place where you really don't want it?

It houses the rubber cushioning for the rear coupling's draw-bar.

Draw-bar cushioning

And in more detail:

After a good clean-out

When the cover was first taken off, there was an inch or so depth of general rusty scale and carp-related material which had to be removed. The cause of this was clearly due to water running down the outside of the cab rear on to the top of the buffer beam and in through a convenient slot left for the purpose.

Water ingress slot

Quite why this slot is there is unclear unless the cover plate was originally hooked through the slot from the inside as its top fixing? Even though not used in that way, it's not a very clever idea as water had seeped in over the years causing the rusty scale etc.

Slot from the inside

The slot will be blocked with a weather-proof sealant before finally making and fitting a new cover plate. In the meantime, it's had a good coat of red oxide primer ready for a black top-coat to keep the rust at bay.

Somewhat smarter than before!

Coming soon: making the new cover plate when, this time, I don't forget the camera when rolling its curved shape and bending its flanges!

Completely Baffled!

The last article on the superheater showed the pattern made to cast a baffle plate for supporting the centre of the superheater and directing the hot fire-gases through the tubes instead of up the large hole in the centre.

The baffle plate has now been cast in SG420-12 Malleable Iron by East Coast Casting Co Ltd of Thetford and fitted to the superheater assembly by Grant Goold.

Baffle plate in place

The baffle plate largely blocks the gap through the centre
so the heat passes through the tubing

View from above showing the support rod to the top plate

The superheater and boiler top plate assembly are now ready for fitting into the top of the boiler via the top of the cab (where there is not a cab roof yet!).

'Ello, 'Ello, LO!

Apologies for pinching this from the SDC Website!

On Saturday 11th Feb 2012, at the AGM of the Sentinel Drivers' Club in Liverpool, Tony Thomas (records officer) proposed and various members of the Goold family seconded me to take over the committee post of Locomotive Officer for both steam and diesel technologies. This I have gladly accepted and hope I can do the post justice.

The post has been held for many years by Martin Hawkins, uncle to Sentinel 7109's boiler inspector Peter Hawkins, a boiler maker in his own right and driver on the West Somerset Railway. So I have quite an act to follow.

To some extent, the task is a blank sheet for me to make of it what I can; the main object being to be the point of contact for anyone with queries about Sentinel locos. Where I don't know an answer, hopefully I can find someone who does!

Tony Thomas has kept records of locomotives still in existence for many years. I hope to make use of his existing information and to keep it up to date using a website, 'blog or such like.

Wish me luck!