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Next SI Project - Sentinel!


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Having 'finished' the Barclay Diesel my thoughts turned to the next one on ze list - and I decided to have a go at this, a Branchlines Sentinel (or SentinAl as they put it).  A cast kit of parts intended to fit a Tenshodo Spud, it would appear, on the face of it, to be a quite simple proposition.  However, we all know where those thoughts lead don't we!  Building it for P4 means that, in reality, the  scalded cat performance of a Spud is not really what I want so I will have to think of something else.  My intention is to build something similar to Gordon A's High Level 'under the counter' etch for the Roxy Planet (which has a 4-wheel drive through a train of gears) but extending it by an extra set of idler gears to make it nearer to the prototype's 7'0"/28mm wheelbase.  To this end I have had a chat with Chris at HL and ordered what I hope will be the correct assortment of bits to do just this.  In the meantime, awaiting delivery, I have started to clean up the castings to try and ensure a close fit between parts which I intend to low-melt solder together.  I will have to make a set of frames for the chassis as per the Planet but can't start this until I have the etches from Chris to be able to set out axle holes etc.

 

Here are things as they stand at the moment.

 

1233352881_SentinelParts.A..jpg.e630d4967bc49098b5a779e89164c43f.jpg

 

Further communiques will be issued from 5050 Towers as the situation develops......................

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Is that the old Nu-cast kit? I'm interested to see how you introduce chassis flexibility in a loco with spur gear drive. I've got one planned and a couple of options are under consideration but I'm still not sure...

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I believe it is.  Branchlines/South East Finecast have re-mastered a lot of old kits from a variety of sources.  When I get the parts from HL I'll be able to work out how to build the chassis in more detail.

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Hi Paul, 

 

I've one of these to build as well but using the Tenshodo Spud. 

 

Recently I've been renovating an earlier plastic bodied version. Here's the link to my blog entry:

 

 

Hope that's of some help. 

 

I'm awaiting a reply from Steve at Railtec regarding custom transfers. Guard irons to fit and painting this weekend. 

 

Cheers, 

 

Mark

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Yesterday saw me putting the main body parts together, using low melt solder for the sides and ends and some 5 min. epoxy for the bunker top and windows.  Shall we say that the fit was 'adequate' after some filing.  Not perfect but better than some.  Today I've been fettling the fit of the roof which is still not brilliant but I would prefer to keep it rather than substitute a sheet brass one to keep the weight up.  I've also fettled the fittings which again aren't brilliant so they may be substitited for some scratch built ones - especially the blob of white metal masquerading as a whistle.  To check on constructional details for the class I've found the RMWeb thread on the Dapol 7mm version (https://www.rmweb.co.uk/community/index.php?/topic/128499-sentinel-y1y3-in-7mm-scale/) and discovered from photos thereon that the top of the 'bunker' is completely wrong.  It appears that there should be visible the top of the water tank in the centre with a coal bunker either side, something that isn't apparent when viewing photos taken at ground level.  I would like to replicate this by cutting the offending bits away and creating a pair of shallow 'bunkers' but the trouble is that I don't know yet how much space there will be below this once the motor and gearbox is fitted - and in which end these will be as I would like to incorporate a basic representation of the boiler and cylinders/engine in the cab end.  Does anyone have a photo/photos of the cab interior?

 

1613703455_SentinelEarlyBuild.A.jpg.fb7cded7e8532445a07ec86888953640.jpg

 

Sorry it's slightly out of focus - but you ain't missing much yet!

 

Chain drive in 4mm David?  Wasn't aware Branchlines offered this.

 

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Thanks to 46444's blog I have just ordered chimney etc. from DCC Supplies Dapol spares list.  A very useful source that I'd not seen before.  Thanks for the info.

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The Middleton Railway Centre has an ex LNER one which they have restored to working condition. Not too far away from you and they're a very friendly museum. Perhaps this isn't the right time though.

I have the Model Rail Sentinel and I have just piled coal up over the bunker/water tank, Roger Carpenter has photos showing this.

I have the gubbins in the cab and two crew hanging out of the windows to hide the motor and the electronics, but the vertical boiler was at the back (there's a spare one to be seen in the car park at Middleton) and the control panel at the front. The windows at the side are fixed I think and those at the front IIRC slide inwards and might overlap but I'm not sure. Cab colour is black below the window sills, white above but it probably got pretty dirty in there.

I think the LMS ones had Midland pattern whistles, AGW do lost wax castings. Don't know what type whistles for LNE, GW or industrials, sorry.

Cheers

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Tried to do a bit of work on the bunker top this morning - and it and the window casting came loose.  Useless 5-minute epoxy for you.  I've never got this stuff to work properly or actually stick!  It just peels off like silicone sealant.  I've now put it to one side awaiting deliveries from various souces and have opened up a High Level Pannier tank chassis kit instead.

 

But one of those doesn't really apply to this section of the forum.....................

 

Edit - unless of course one is modelling a South Wales colliery.

Edited by 5050
Remembered South Wales colliery panniers!
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8 hours ago, PenrithBeacon said:

It's the Delrin system and it does include 4mm in the range, just checked to make sure :(

You can use the chain in 4mm, it's a bit difficult in 00 because of its width but easier in EM or P4, the smallest sprockets (8 tooth) give an effective diameter with the chain of about 9.75mm.

I've used this recently in an EE type 4 (EM).

 

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Mmm, with 10.5mm diameter wheels there won't be much clearance.  As I've already ordered parts from HL I'll stick with them at the moment - but who knows..........

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On 02/05/2020 at 09:39, Ruston said:

I have castings for a Sentinel boiler and engine that may be of some use to you.

I will have to wait until I've sorted out the position of the motor etc. to see how this impacts on the space in the cab.  Is the boiler the same style as the one in the Dapol loco?  I've only seen the computer derived images of the one they've fitted.

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3 hours ago, 5050 said:

I will have to wait until I've sorted out the position of the motor etc. to see how this impacts on the space in the cab.  Is the boiler the same style as the one in the Dapol loco?  I've only seen the computer derived images of the one they've fitted.

I've no idea about any Dapol model. What I have is for a Langley Models Sentinel lorry. Whatever differences there may be, you're not going to notice in 4mm and through those little windows.

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Thank you for these david.  I had seen the drawing which helped me earlier but not the Alderney photos.  Useful indeed.  However, having now received all my bits from High Level, Alan Gibson and DCC Supplies I have taken some preliminary 'measurements' and I think the cab will have a fair bit of motor in it so there may not be any room for boiler etc.  It will be a pity as they are so distinctive.

 

I'm currently trying to work out how best to bodge adapt Chris's Planet etches and gears to fit.  Its doing my head in - my 'Braynerts'...............:wacko:

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This week I have been mainly building chassis. I roughed out a drawing of the main side elevation with dimensions to assist in planning the chassis which is quite basic and really only serves to hold the wheelsets in alignment while putting it all together.  The HL Planet etches have been modified to be able to drive from the centre of the chassis with an idler gear each side.  This meant drilling another hole directly in line with the ones already there - at the correct spacing to ensure proper meshing of the gears - and modifying the 'swing arms' so that there is a pair at each end pivoting on the centre drive shaft.  One end will be fixed for a rigid axle (soldered to the main gearbox etch) and the other end will pivot to create a compensated suspension as per the original HL design.

 

Here are the main parts laid out on a piece of ceiling tile which came in useful for 'pinning' the various parts down with 2mm rod to check gear mesh etc.

1830259622_SentinelModifiedHLetches.1.A.jpg.cdc95576c0c2c026f08b0fb393f123ff.jpg

 

The HL etches with some modifications.  thankfully Chris sent me 2 etches (I needed the 2 sets of swing arms) as I made my first set of new holes (the bottom centre ones) slightly to high and the meshing was a bit tight.

 

894274477_entinelModifiedHLetches.5.A.jpg.712f432d8d61070c92967149bfa9df4b.jpg

 

Checking the mesh of the gearsfrom the datum point of the centre axle.  The end holes of the 'arms' has a hole larger than 2mm and Chris supplies a 2mm bore brass bush for these.  the black is a permanent marker for scribing lines and hole positions.

 

1664496316_entinelModifiedHLetches.2.A.jpg.b801b78b330aabd1cb14fbb25aa20f3d.jpg

 

The modifies etch prior to final bending.  the bottom side 'extensions' have been trimmed back to clear the middle axles of the swing arms.  Note that Chris now includes a set of fixing holes for Mitsumi style angled hole motors

 

786036521_entinelModifiedHLetches.3.A.jpg.bf0088852b3e0c12aae0267fce1006af.jpg

 

Setting out the side frames for the outer chassis based on measurements taken from the body castings and the HL etches.  the 2 frame sides were soldered together, axle holes drilled and the shape cut with a piercing saw.

 

1111769697_entinelModifiedHLetchesandchassisblanks.1.A.jpg.f17aad50d7101806708852291babf8f6.jpg

 

The width of the swing arms prior to being 'narrowed so they won't show below the chassis sides (hopefully!).  Filed down to the scribed line.  Parts held in some 'soft jaws' made from aluminium angle.

 

798560993_entinelModifiedHLetches.4.A.jpg.14a437bfc8c7e5265760c70e740c16e4.jpg

 

The completed chassis built with some old etched spacers I had in stock plus a thicker spacer drilled and tapped 8BA for a bolt to act as pivot for the compensated axle.  the axle holes this end have been extended downwards and slightly upwards to allow movement.

 

415044991_entinelChassis.1.A.jpg.f32b2a92bcadc810b2c68bfe2bbc3c12.jpg

 

I have now realised that there will be sufficient space to accomodate the motor (which will have to be smaller than the one I had originally intended to use) and gearbox in the bunker end and leave the cab end almost clear.  This means I may be able to fit a boiler etc. after all so negotiations will commence with Mr Ruston to see if the one he has is the correct type.

 

All I have to do now is start putting it all together........................

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A quick update on 'progress'.  I've built and unbuilt the gearbox several times to check meshings etc. and to add some brass tube spacers to hold the gears in the correct alignment.  When I've done this before I've just left them loose but this time decided to solder them in place as this makes final assembly much easier.

 

The 'fixed' arms are soldered in place on the outside of the main etch and the 'swinging' arms will fit inside, pivoting on the central axle.  The right hand one has been filed back on its top edge to clear the intermediate double gear down from the motor.  The 2 gears at the top are the 10 tooth final drive ones that are an interference fit on the end axles, the intermediate idler gears are 8 tooth and are a sliding fit on the axles.

 

1757617272_SentinelModifiedGearboxandGears.1.A.jpg.6c637943687b8cb9f115acca601b293f.jpg

 

On assembling this I realised that I had made a fundamental error.  (What a surprise....)  I had soldered the spacer tube on the centre holes of the swinging arms in place and this was preventing the arms from moving sufficiently to allow movement for the compensating action.  A quick touch of the iron and a clean up of excess solder soon sorted this out.  Thankfully....

 

Now to fit the wheels, motor, finish the body etc.  Hours of fun still await!

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  • 2 weeks later...

I thought it was about time I brought everyone up to date with progress.  I have been busy, labouring away most mornings after watching 'Minder' with my breakfast.

 

I fitted all the gears, spacers and wheels to the inner chassis - and they seem to run quite freely when fitted into the outer chassis frames.

 

1979454756_SentinelChassisassembled.A.jpg.904cdbc627a2ecae327b282953a6b0bb.jpg

 

Another view from below.

 

4691080_SentinelChassisfrombelow.A.jpg.3cb75d031bf602edb614f41e093d39de.jpg

 

A view from above showing the size of motor I am using in order to get everything into the space below the bunker.  The screw is for the rocking axle pivot and will be cut down in due course.  Everything is painted Black to try and make it all a bit more inconspicuous when fitted into the footplate and body.

 

1723761512_SentinelChassisandMotor.A.jpg.b0503beb00424455b3203fe82e8f49f6.jpg

 

Inner and outer chassis attached to the footplate with axle guards expoxied in position.

 

1931136815_SentinelFootplatewithchassis.A.jpg.32221423855e657c02da7217fd8f50f2.jpg

 

The footplate and solebar unit complete with brakes (from an odd fret I found in my 'likely to come in useful' box (it did!) and guard irons from scrap brass strip.  Brakes and guard irons are attached to the inside of the solebars.  Sanding pipes (0.7mm wire) still to be fitted.  The whole given a wash of metal black to blend it all in and act as a base coat for paint.  The 'slot' in the centre of the solebar is for locating the cab steps acquired from DCC Supplies from the Dapol spares range.  A bit (lot!) more accurate than the cast ones.

 

1771502214_SentinelFootplatewithpartsadded.A.jpg.eaff2a8ee3f2334989948e66c74a1583.jpg

 

Body and solebars with buffer housings from Alan Gibson rather than the cast ones in the kit.

 

1197169471_SentinelBodyandFootplate.A.jpg.218e4bdba7a5e9c7f921cdc38ea55ae7.jpg

 

A trial fit of it all - with the roof back to front!.  I've made a boiler and brake standard for inside the cab but I doubt they'll be very visible especially with glazing and crew member leaning out of the door aperture.  The Dapol bunker top looks good and fits very well with only a little filing for a good fit.

 

1886977826_Sentinelpartbuilt.A.jpg.5c4ca5ca004cbba68ae9d9ea0c8c18c3.jpg

 

Next to test run on leads, fit pickups, fit buffers, chimney, tank filler and whistle - and paint!  Nearly there:dance_mini:

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No photos this time but just a quick word to say that - IT WORKS!  I fiited pickups this morning and did a temporary connection to the motor and it ran fine.  Just the wrong way round of course:rolleyes:  Motor out, turned over, wires soldered on and off it went running like a dream.  You know, the nice one with the beautiful young lady etc etc. not a nightmare.....................:diablo_mini:

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