7mm Ever watchful and on the alert.

[Dave]

Sentinel steam this time. 100HP post-war type. It's probably got an official class or designation but if it has I don't know it.

Anyway... It's a kit by Meteor Models and here's the pic on the box.



It's only small but I've a feeling it's going to take a bit longer than the other two loco builds that I've posted on here.

 

[AJC]

Interesting. What, in may ways, looks like a perfectly reasonable kit let down by poorly drawn grilles; they look as if they were drawn in freehand with a felt pen in a fashion that MTK would have blushed at... I have a notion that Archer Transfers do some transfer louvres:

http://www.archertransfers.com/AR88036.html

These cannot be any worse. RT Models are doing one of these in 4mm some time this year, looking forward to that.

Adam

 

[Dave]

Yes, Adam, I agree with you about the louvres but then there's worse to come. The instructions even say that the chassis was wrongly drawn. The holes for the bearings are 1mm too low on one side of the fold-up inner chassis.

 

[AJC]

Well at least they've taken the trouble to say so; it seems that the Colin Massingham comparison was more apt than I imagined. Good. Grief.

Adam

 

[Steph Dale]

Ahem, don't anyone mention the phrase 'merchantable quality'...

Frankly if it were mine I'd be too embarrassed to sell it. Tim does some great kits and some people will buy this model as an introduction to the Meteor range. Surely he's shooting himself in the foot every time he sells one?

Steph

 

[Buckjumper]

Worth linking up with Sandy Harper's thread of the build over on RMW as there are more hurdles to clamber over, though I see you've already found it Dave

The fun starts here.

 

[Dave]

I'm not sure those Archers transfers are the solution to the louvre problem. They may be fine in 4mm but in 7mm I think they'll look too flat. I may cut the sections out of the etches and replace them with home-made plasticard items. It's a method I used when scratchbuilding a standard gauge 44/48HP Ruston in 7mm.


I do have a solution to the chassis problem though.

I detest flimsy fold-up chassis so the best place for it is as scrap. In its place will be one made from 1/16th brass plate and solid brass spacers. The above photo shows the kit chassis and the chassis and swinging arm patterns I have made ready for profile milling (four times the size of the finished item). I've designed it to be fully sprung but I may fix one axle. I'll decide as the build progresses.

My friend, John Taylor, will mill the parts and should be calling in later today to collect the patterns.

 

[AJC]

I have the same doubts about the transfers in 7mm; they may be a bit flat, but as I said, they can't be any worse. The proper engineering solution for the chassis looks the business at this stage.

Adam

 

[Dikitriki]

I like the approach to a milled chassis.

One thought; do you have enough metal around the bearing hole on the swinging arm? I'm guessing it's something around 1.25 mm once it's been reduced?

Richard

 

[Dave]

Hi Richard,

Yes, something around that. The hole in the pattern has been made slightly smaller (in scale) than the finished item will need. The actual parts will have a 1/4in. hole but I'll open the holes out to this to ensure a tight fit for the bearings, which to be enclosed ball races. I think the metal around them will be sufficient as it's 1/16th thick after all.

 

[adrian]

I'm not sure those Archers transfers are the solution to the louvre problem. They may be fine in 4mm but in 7mm I think they'll look too flat. I may cut the sections out of the etches and replace them with home-made plasticard items. It's a method I used when scratchbuilding a standard gauge 44/48HP Ruston in 7mm.

There is this solution to the louvres!







Courtesy of Gerald Wingrove

http://www.wworkshop.net/2.3_Alfa_Build/Gallery-16.html#grid

 

[Dave]

That looks like a fantastic piece of kit, Adrian, but just a bit of overkill for one little Sentinel kit, I think

Having just posted a new thread and saying why this one's on the back burner, look what just arrived whilst I was typing out the reply in the new thread.


And just in case anyone is still wondering about the thread title, here's the Sentinel trade mark.

 

[Dave]

Today I took a drive through the bandit country of Hull and across the badlands of East Yorkshire to visit my friend Ian Cornwall, a member of Hull & District Society of Model and Experimental Engineers, to drink tea, eat biccies and to use some of his wisdom and machine tools to make some bits for the Sentinel.

1950s Raglan milling machine to open out the holes in the suspension arms.


109-year old lathe to make the boiler from solid brass bar. The boiler in the kit is a hollow cast resin item so the brass one will add a lot of extra weight for traction.

 

[Dave]

Again, to cut a slightly less long story short...

 

[Dikitriki]

That looks a really good solution to the chassis with all the arms sprung. Does it run as well as I think it ought to?

Richard

 

[Dog Star]

Again, to cut a slightly less long story short...

Best Borchester that green 'un.

 

[Dave]

That looks a really good solution to the chassis with all the arms sprung. Does it run as well as I think it ought to?

Richard

It runs superbly. I had a bit of trouble with one of the sprockets slipping on the axle so I drilled through the sprocket and axle and put a brass pin through. After that it was fine. It uses a Mashima motor drving a Roxey 46:1 worm and wheel so it can go slowly enough without revving too much.

I crammed lead sheet and shot into the "bonnet" and the finished loco weighs 650g. I could have got more in but I think that's plenty.

 

[alcazar]

I'm sure I remember an article in an early MRJ about making louvres in thin brass/nickel silver sheet, by stamping them using a home made tool in a rivet press?

I'll have to dig it out.