Dikitriki's 7mm Workbench: Scratchbuilt Wagon

[dikitriki]

Hi

 

Last night saw the right hand side valve gear fitted...

 

 

and it's all running very smoothly. On to the reversing links tonight.

 

As a taster, I put the whole lot together to see where I was going...

 

 

OK, it looks like a crab. It won't as yet go round 6 ft radius curves as the pony wheels clout the front steps, and the fall plates do not have enough vertical clearance, but that's for a bit later.

 

I then took it all apart to look at the tender chassis. Oh dear!

 

 

Rusty wheels and axles, excessive sideplay.

 

 

A scoop that bears no resemblance to LMS scoops, brake pull rods that didn't fit - look what was done at the front - and undersize etched brakes. No scoop counterweights, no brake cross shaft, vacuum cylinder or cranks. Well, nothing that a complete strip and wholesale replacement of the components can't cure. Actually, I get my kicks from detailing underframes as you might have guessed!

 

 

The detailing parts are coming from Ragstone Models, with Griffin brake hangers/shoes, for this bit.

 

 

Alcazar - I do not know for sure where I got my miniature top hat bearings. I bought a reasonable stock a few years ago, and the packet is not labelled. I am reasonably certain they came from Ron Chaplin, but he seems to do less bits, and more motors and gearboxes these days.

 

That's it I guess until Thursday when RMweb is reincarnated, again.

 

Richard

[MerseyMan]

Absolutely stunning work Richard. Your posts are always a pleasure to view. Keep them coming.

[dikitriki]

Hi

 

I have now tidied up the tender frames, cleaned the rust off the wheels and axles, blackened the wheels and built the scoop and its operating mechanism. It's already looking a million times better than the starting point. All the scoop gubbins came from Ragstone Models (originally MMP) and it was fully working before I soldered it in place. It is also the answer to Scale7JB's question what should he make work next!

 

The pictures will show you far better than words, so here goes.....

 

 

 

 

 

 

 

 

 

Next are the transverse braces.

 

Richard

[Scale7JB]

It is also the answer to Scale7JB's question what should he make work next!

 

 

Haha, it has been suggested by Peter Hunt, leader of our pack, but my reply was this it was likely that the scoop would be dropped by mistake, and either hit a rail in a turnout, and rip it off, or cause a short that blows everyones DCC engines up...!

 

I still need to build the working brakes on the K2 tender though..

 

JB.

[alcazar]

You lot need to get lives.

 

But seriously, every new "working bit" I see just leaves me gobsmacked.

 

Are those Slaters' hornblocks on the tender?

[Scale7JB]

 

But seriously, every new "working bit" I see just leaves me gobsmacked.

 

 

Once you have the electronics in place, it's really quite straightforward to get things to work on a servo.

 

JB.

[3 link]

Hi Richard,

 

Will you be fitting extra pick ups on the tender, or be using the American style pick up method ?

 

Regards, Martyn.

[Horsetan]

Once you have the electronics in place, it's really quite straightforward to get things to work on a servo.

...

 

Hmm. Doing it in 4mm scale....hmmmm....

[Scale7JB]

Hmm. Doing it in 4mm scale....hmmmm....

 

Sorry, last hijack... I'm sure it's possible, just got to find a chip and servo small enough.. :icon_thumbsup2:

 

JB.

[dikitriki]

You lot need to get lives.

 

But seriously, every new "working bit" I see just leaves me gobsmacked.

 

Are those Slaters' hornblocks on the tender?

 

 

Hi Alcazar

 

Yeah, that's what my therapist said. I think most of my Heyside gang think I'm mad anyway.

 

They are Slater's hornblocks. The original builder fitted them securely, pretty much in the right place, so I just tidied them up and freed the movement. I shall fit springs at a later stage.

 

 

Hi Richard,

 

Will you be fitting extra pick ups on the tender, or be using the American style pick up method ?

 

Regards, Martyn.

 

Hi Martyn

 

Yes, I shall fit split axle pick ups to the tender. The engine has one side shorted out and will have plungers fitted to the other. I may carry one of the wires through the drawbar, meaning only one lead to plug in. It depends on where the drawbar pin goes on the tender chassis, and I won't know that until I have fitted the brake cross shaft at the front.

 

 

Sorry, last hijack... I'm sure it's possible, just got to find a chip and servo small enough.. :icon_thumbsup2:

 

JB.

 

Hi JB

 

I did consider making it working with a servo, but couldn't be bothered. I was going to attach a vertial pin to the horizontal wire rod between the first and second axles, and mount the servo on top of the tender chassis.

 

 

Two other points.

 

First, I was having a trawl of the JLTRT site when RMweb was in intensive care, and the ex Chowbent crab is again available, I understand with a resin smokebox, boiler, firebox unit. I may well approach JLTRT to acquire one of their resin boiler units to fit to the LG crab. That will mean that the only Jidenco etches I have to use for the LG body will be the footplate and cab. It also means that if anyone is mad enough to want to do what I have done, they can.

 

Second, the scoop. The shape of the bottom of the scoop is not right for a crab, there should be a greater flare at the bottom, looking in profile. The result is that it is not deep enough from top to bottom. The shape seems to be more akin to the BR standard design, and optimised for the smaller wheel diameter. I therefore had to compromise in the way I built it. To get it to look right from normal viewing angles (see top picture in my last post), it is modelled pretty much in the down position, though it looks to be up because of the lack of flare, and the separation from the rail. Next time, I would put a couple of washers where the scoop body is attached to the chassis, and make the mouth of the scoop a little more 'up'. But it's all a compromise somewhere along the line isn't it?.

 

Richard

[MerseyMan]

Hi Richard. Just one question. How did you strip all the paint off all the parts before starting work. Did you use some kind of stripping agent like Nitromoors or something else a little more cruder like oven cleaner?

[dikitriki]

Hi Richard. Just one question. How did you strip all the paint off all the parts before starting work. Did you use some kind of stripping agent like Nitromoors or something else a little more cruder like oven cleaner?

 

Hi

 

The loco chassis, I used cellulose thinners which got 95% off, and then used a fibreglass brush.

 

The tender chassis, I removed all the parts and then mechanically cleaned the frame unit - sandpaper, wet and dry, fibreglass brush. I would have used cellulose thinners, but for the fact that I suspected the hornguides were glued in with Araldite, and I didn't want to run the risk of them falling off! The existing brakes and scoop hit the bin without being stripped!

 

Richard

[MerseyMan]

Hi

 

The loco chassis, I used cellulose thinners which got 95% off, and then used a fibreglass brush.

 

The tender chassis, I removed all the parts and then mechanically cleaned the frame unit - sandpaper, wet and dry, fibreglass brush. I would have used cellulose thinners, but for the fact that I suspected the hornguides were glued in with Araldite, and I didn't want to run the risk of them falling off! The existing brakes and scoop hit the bin without being stripped!

 

Richard

 

Many thanks Richard, thats most helpfull.

[dikitriki]

Hi

 

I've now finished rebuilding the tender (well, almost)

 

One of the problems with fully detailing tenders is maintaining access when everything is in place. Never more true than with the transverse braces which are a pain. The first picture shows my solution. Cages just to carry the braces which are invisible when all is together. Otherwise it's a case of attaching the chassis to the body permanently, and not being able to remove the chassis/wheels without unsoldering something.

 

 

Here you can see the separate brake and scoop operating systems. The adjusters on the rodding are made from tube with a nut either end.

 

 

 

Here is the front end the right way up - a bit dark - but the strengthened draw bar pin is evident, as are the nuts on the end of the brake spreaders.

 

 

And all together

 

 

The only things remaining are to split axle (is that a verb?)the wheels and clean up the rather ragged mouldings on the wheel centres, and fit the miniature connector to take the power to the engine. I haven't given the body a detailed inspection yet, but it's looking OK at the moment.

 

Richard

[Dusty]

Might be a split infinitive if you're not careful Richard...On a serious note those carrying frames for the frame stretchers are a good idea. Did you make them using a jig?

[dikitriki]

Might be a split infinitive if you're not careful Richard...On a serious note those carrying frames for the frame stretchers are a good idea. Did you make them using a jig?

 

Hi Dusty

 

That'll be to boldly split axle then

 

No jig. I made the first by trial and error, and careful measurement, and then matched the other three to that one. Since I was using relatively thin nickel-silver, I was able to tweak them to final position as necessary. It still took quite a while and lots of repositioning though.

 

Richard

[dikitriki]

Hi

 

I did warn you that there would be changes and disruptions to the workbench from time to time, and so it is now. I have had to put the crab down as I am waiting for parts to arrive, as I am stuck on the underframe (live steam injector and grease separator) and the cab interior (driver's control valve). In the meantime, I have taken the opportunity to give it a good test on Heyside, and it is running in nicely.

 

 

Another of the locos I had identified as being essential to the Oldham Loop area to set the scene is an Aspinall A class 0-6-0 tender loco, so I have been getting on with this. I had started the tender some time ago, but come to a stop whilst deciding how far to go on the loco. I had already decided to install inside valve gear when I was approached by Iain Young to do a set of his as yet unreleased Joy valve gear, to take lots of photos for the instructions and generally provide feedback. Sice this was appropriate for the Aspinall A, it moved up the list, and work started on the chassis.

 

Now, inside valve gear in 7mm finescale brings its own problems, enough to make you convert to S7, but I'm made of sterner stuff than that

The first problem is that the cranks are pretty beefy, and there was no way I was getting hornblocks in the chassis. But I had to arrive at some method of dropping the cranks and axle. I was at a loss as to what to do until I realised that Tony Reynalds simply cut the frames for the hornguides. So I very carefully marked the frames to be an exact fit for cut-down Fourtrack hornblocks, and added strips of nickel silver to stop any rotation. Result, very neat and thin working hornblocks. They are retained by adapted cast springs that are screwed to the frames.

 

 

Incidentally, you can see that I have filled in the 2 pick up holes and 1 chassis spacer hole in the sideframe.

 

 

However, just when I was feeling pleased with myself, I realised I had created another problem. My penchant for using cast springs meant that the cranks would foul them. So, on with the extreme kitchen table modelling, and I milled (abuse of minidrill actually) a clearance arc out of the springs. OK, it looks stupid from the inside, but no-one will see that from normal viewing distances, and it still appears that the springs are nice and solid from the outside:D

 

 

 

Now, I'm sure the S7 boys will be feeling very smug at this stage, and there's no doubt I've made far more work for myself by doing this in 7mm finescale, but it can be done, and the most difficult bit is now behind me. I still have to put the chassis together, and it is at that stage that I will find out whether I have marked and cut the hornguides accurately!

 

Richard

[Scale7JB]

 

JB.

[Sandy Harper]

Neat solution Richard.

When faced with a similar problem on a Finney GWR loco, I went down the 'thinning the crank' road, but I prefer your solution.

Sandy

[clemf]

I wish I'd thought of doing that with the hornblocks. Will remember that for the future.

[Rob Pulham]

I have just done exactly what you have done on my scratch build but your horn blocks must have a wider slot in them than mine (slaters) I have had to thin the edges of the cut out's 0.8mm this frames and ease the slots in the horn blocks with a file. I was looking for a solution to hold them in place and you have probably just given me it although I am not sure I can buy springs small enough to suit. I may have to follow Christian's example and make some up from strip. I too have to put them together yet to see if they were marked and cut correctly - hopefully later tonight.

[dikitriki]

Hi

 

Last night saw the basic chassis constructed, and although the wheels are not yet on, I am pleased to report that my cutting of the centre hornguides was accurate. My method of chassis construction is basic and simple, but works every time.

 

I clear the workbench first (an unenviable task as it seems to get back to its previous cluttered state in an hour or so), place a sheet of graph paper down and a sheet of glass on top of that (quite a large piece from an old occasional table - thick and with smoothed edges).

 

On top of that I place 2 identical pieces of angle, as far apart as my sighting rods will allow, and the sighting rods are placed through the bearings. I can now check that the chassis spacers are at right angles to the sideframes, as are all the sighting rods. Because the chassis is the right way up, and I am (in this case) using fixed front and rear axles, I also know that the axles are also aligned and there can be no rock. It's then a case of soldering the frames to the spacers and the bearings to the frames, checking all the while everything is at 90 degrees by reference to the graph paper.

 

I differ from conventional wisdom in that I do not do this by reference to the coupling rods, which I am quite happy to amend to suit later. However sinced they are all milled, I am pretty confident I won't have any problems, and I'd rather get all the axles truly in line.

 

The pictures will make everything clear. I shall do the crank axle next, and then the basic body, as I wish to see where the smokebox ends on the body before doing the cylinders between the frames.

 

 

 

Richard

[dikitriki]

Hi

 

I found time to build the crank axle this morning. Not really something I enjoy, but it's done now. You will note that I pinned it as well, all done in one soldered operation, as I don't want it ever to move. This is one instance when I advocate lots of solder and a big clean up afterwards!

 

It still didn't fit between the frames (springs actually) properly, so more faffing about needed

 

 

 

Richard

[dikitriki]

Hi

 

First off over the weekend, I tidied up the crank axle, and relieved the springs a little more, especially the nut and screw on the inside of the chassis until I had a smoothly rotating crank axle. Then I dealt with the Slater's wheels, shorting out one side, making sure the brass centre on the back was truly flat, adding the crank pins etc.

 

I added the remaining driving wheel springs, checked the chassis was true and square, and attached the coupling rods, which by about 1mm did not match the wheelbase of the chassis. That was dealt with by moving the hole centres by filing, and only making them circular when the centres were exactly right. That's pretty easy to do in 7mm as you can use the hole in the centre of the Slater's axle screw to check centres. I do realise I have gone against all advice here, but I've been doing it for so long, I know how and where I can cheat.

 

3 pictures of the chassis. You can see how tight on clearances the crank axle is (I had to maintain 14mm centres between the crank centre lines), and also how it revolves inside the springs. Nevertheless, I have a very free-rolling chassis.

 

 

 

 

I also got this far with the body (some of which I had done a while ago)

 

 

Nicely designed, I built this on a piece of glass so, again, I know it is square. I need to build enough of the body to establish where the rear of the smokebox falls in relation to the chassis to know where the front plate for the cylinders is located on the chassis so I can go back to the inside valve gear.

 

Richard

[dikitriki]

Hi

 

In between trying to sort out baseboard ends on my layout, and get my family back from abroad, I have managed to progress the Aspinall.

 

I built enough of the basic body and mounted it to the chassis, so I know exactly where the rear of the smokebox is to set the location of the valve chest in the chassis frames.

 

 

The slide bars were cleaned up such that both the crossheads and valve spindles moved freely, and that the slide bars fitted through the slide bar support bracket without pinching. The support was soldered to the slide bars after determining the appropriate distance from the face of the cylinder block (by trial and error on the chassis, from photographs).

 

 

 

Next stage is to polish the slide bars and attach to the chassis, then think about the connecting rod which I think is waaaay to long. So a complex cut and shut lies ahead I think.

 

Richard