Stevesopwith's S7 Workbench

[Stevesopwith]

I like small engines, and I've always had a soft spot for Sentinels...... particularly the 'sardine can' type used by Frys. I managed to obtain the etches, and castings, for the Impetus kit for this loco, so what follows will be a record of how I get on.

It will have a Mashima 16/26 can motor, driving a Branchlines 80:1 gearbox, on Slaters disc wheels with 1/8th axles. Delrin chain and sprockets will couple the axles, with High Level CSB suspension.

The kit is perfectly useable as it is... the castings are very good.... but I will make a few changes, partly to improve the level of detail accuracy, but also because I've evolved my own, different, way of doing things.

I've spent some time in research, and found some very useful sites:

www.embsayboltonabbeyrailway.org.uk
'Sentinel Locomotive 7109' a blog based gold mine ! ( Google it.)
www.avonvalleyrailway.org.uk

The last one is actually restoring the Fry's Loco, and I'm hoping to carry out a survey sometime in September. It will help me sort out what goes where , particularly under the footplate, because it's not your usual arrangement ! The attached GA will give some idea. Isn't it cute !

 

[Eastsidepilot]

Nice project Steve . I have a photo in a book of an engine out of an LNER Sentinal lying in a yard somewhere.

Col.

 

[AdamF]

Looking forward to seeing how this develops!

 

[Rob Pulham]

That looks good Steve, the Y10 Sentinel is on my list of things to scratch build. I intend to use Adrian's plans as a starting point.

 

[Stevesopwith]

Rob. On the Sentinel Loco 7109 site there is a side view drawing of the double-ended version.

I'll try the 'address'. It's:

http://sentinel7109.blogspot.co.uk/search/label/Other Sentinel Locos

Alternatively, find the site, find 'Other Sentinels' in the left hand navigation, which will take you to '200Hp Pre-War Sentinels.

The rest of the site is a treasure trove of information and pictures of the restoration, featuring boiler, engine, and underframe transmission details. Essential viewing!

I also have the Don Townsley drawings of the Radstock Sentinels, from Model Railways 1975. A very close relative of the Y10, it offers alternative versions of the bonnet and cab profiles to compare with Adrian's drawings.

If you PM your e-mail address, I can send you a copy if of any use to you.

Graham..... Sopwith has quite enough on his plate mastering crossing Vs !

I'll be posting updates on the Fry, once the Olympics are over.

Cheers... Steve.

 

[Rob Pulham]

Thanks Steve, I had a quick glance around earlier but confess to missing the Y10 stuff. You have a PM

 

[Stevesopwith]

The kit has a rigid, fold-up chassis which is perfectly useable, especially if fitted with some form of compensation.
However, although the full size loco doesn't have any inside frames, I wanted to try 'proper' S7 width frames and sprung hornblocks, partly as preparation for the Wantage steam locos.
Also, while I have a general design idea, the details will evolve as work proceeds; and that's much easier if the frames are separate units till final assembly.

So... two frame blanks were soldered together and the outline and axle hole positions marked. At each end a further hole was added on the axle line.
Once clamped to a piece of 12 mm ply, the whole unit was clamped to the drill table, using a 4 mm pin point axle to locate in the hole marker of one of the end holes. Using successive drill sizes, this hole was opened up to 2 mm. With the ply still clamped, the metal was removed, and it's hole gently broached to a snug clearance fit on 2 mm steel rod. ( more 4 mm axle. ) Using the drill as a press another 2 mm rod was pushed into the ply, and the metal replaced over it. This process was repeated for the remaining three holes, the two axles opened to 1/8", the last to 2 mm.

I now have a jig that will locate the axleboxes relative to the frames once I have cut out the outline and hornguide slots.

 

[Dog Star]

I do like the idea of sacrifical ply as a drilling table.... and the ply spacer blocks to ensure tightness of fixing, will not be long before something similar appears in the workshop of the Sruft's Junction Railway .

regards, Graham

 

[Stevesopwith]

The next job is to use the High-Level Jig to fix the positions of the 4mm Markits WD handrail knobs that act as pivots for the spring suspension wire.




These were drilled, along with those for brake hangers and pick-up plates, and the frames were cut to outline, along with the hornguide slots, and separated.

With the frames relocated on the 2 mm rods, the previously assembled guides and blackened hornblocks were placed on the 1/8" rods, and the guides soldered to the frames, using the RSU and Carr's solder cream.
No problems with solder getting where it shouldn't...... very easy!

 

[Dog Star]

However... ...as preparation for the Wantage steam locos.

I know that the subject of the workbench is currently a Sentinel... how does a Sentinel of whatever shape or dinky-ness align with engines from the WTCo.? . The question is kind-of a request to "tell us more" about the plans for a Wantage layout .... that will teach you to talk to strangers at Aylesbury.

The Fry's engine does look rather a cool and cheeky little -4-T so please carry on with the details, the photos and the techniques. Speaking of which, I am sorry to read that young Sopwith is having difficulty with his Vees - maybe if you held the file then Sopwith could move the jig around with his tail?

regards, Graham

 

[Stevesopwith]

Graham,

You are right of course.... the Wantage never used Sentinels, but I suggest they'd have been a better bet than some of their purchases.

Besides it's obvious appeal, it will be a try-out of various ideas for the remaining tram loco, and the two steamers; including CSB s, the chain drive, and even perhaps the Protocab system.

Incidently, in previous posts it might have been clearer if I had written about the use of 4mm *Scale*, ( like S4 ..) axles and handrail knobs.

As far as the Wantage Project is concerned, I'm hoping to give it full coverage once the Sentinel is finished.
In the meantime here's a view from a dormer window at the back of the Butchers in Mill St:



The baseboards, track bed and track plan are done. That's a 'portable' two track sector plate fiddle yard in the background, and there's about five feet of 'main line ' off to the left. The Crossing Vs and Switch Tongues are complete and awaiting the connecting rails....... I estimate about two month's work once I get going.

The building mock-ups are the result of lengthy study and where possible, field surveys, and have been used to check their positions against maps and photographs. Proper models will follow in due course.

This project has been ongoing since about 1973.... so I've nearly finished it!

 

[Eastsidepilot]

............This project has been ongoing since about 1973.... so I've nearly finished it!

1973 ! Steve, had my first Bonneville then and hair . Layout looks great mate, I like the mock-up buildings, too good for mock ups.

ATB, Col.

 

[Buckjumper]

This project has been ongoing since about 1973....

There's hope for us all!

 

[Buckjumper]

1973 ! Steve, had my first Bonneville then and hair .

In 1973 you had more hair than me

 

[Eastsidepilot]

In 1973 you had more hair than me

Yep, just like Steve but it was black........then.

Col.

 

[28ten]

I like that

 

[Dog Star]

There's hope for us all!

What makes you think that comment includes the High Priest of Procrastination?

 

[BrushType4]

The layout looks amazing. Have you got a trackplan and size, any details to share.

 

[AdamF]

The layout looks superb - the mock ups are fantastic! I have a big soft spot for the Wantage Tramway Co so will be following this with intense interest.

What are the approximate dimensions of the whole set up?

 

[Stevesopwith]

Thank you all for your interest..... I'll start a thread in the Layout Section very shortly.

Back to the 'Fry'......

I copied the general outline of the kit frames, with the shapes at each end representing the visible profile under the footplate. These areas also provided a place for the 2mm locating pegs.

In fact the loco doesn't have insde frames at all; the rear plates, supporting the brake operating crank rod, seem to be bolted to the footplate, or cross members, while the shapes at the front are actually gear covers, about 6" thick, and centred 4 feet apart. Neither are exactly in line with the inside frames.

So... these redundant parts were cut from the frames, and new parts made. The rear brake plates can be spaced out from the frames to the correct width, once I have carried out the survey in early Sept. Being removeable will also help with the component assembly, there's a lot of bits! The front gearboxes are laminated from three sheets, giving a better representation of their thickness; and they too can be removed for further detailing, eg the bottom sealing plate with nuts and a draintap. Notice the little slot on the inside....when covered by a further small plate held on by the fixing bolt, it will retain the bent end of the suspension wire.



You will notice that the mounting hole for the front brake hanger goes through the top of the gearbox cover. Of course it doesn't do that really...... the hangers are actually fitted to the outside frame plates, along with the springs and axleboxes; but to do that on the model would start to get complicated, and we wouldn't want that!