GRS Kit for LMS 3F 0-6-0T ("Jinty")

[John Candy]

GRS Kit for LMS 3F 0-6-0T ("Jinty")

If you have one of these kits awaiting construction, I recommend that you do not commence assembly until you have read the notes which will follow, as construction progresses.

As background, this kit was acquired as part of an exchange deal (which included the "Peckett" kit which I have converted to a Bagnall and is covered in another thread in this forum and on www.g3madesimple.org.uk ).

The kit had been subject of a construction attempt (thankfully aborted at a very early stage).
The builder was clearly "out of his depth", since everything which should have been soldered or screwed had been fixed with superglue (even the crooked and loosely-fitted hornblock guides/keep plates were held in place by superglue)!!
Fortunately, he had not got very far before abandoning the project and it was an easy task to completely disassemble the chassis, running plate, body into its components parts.

Now ready to recommence construction, some prototype research was undertaken and the GRS instructions examined.

Firstly some notes on the prototype.

The first batches built did not have the cut-away hole in the side tanks which gives access to the rear sandbox fillers as on the later batches ( the rear sandboxes on the later batches is mounted lower than on those without the cut-away). The original batches without the cut-away were filled from the tank top.

Nearly all these LMS 3F tanks were built by contractors (i.e. not in LMS workshops) and there are detail variations between batches.
These locos were all built with right-hand drive but many were not fitted with vacuum ejectors which, when photographed from the RHS, gives the impression that they may have left hand drive (after the fashion of the 4Fs) but they are definitely RH drive and there was no ejector pipework on the LH side.

A few were (at various times) fitted with vacuum-operated push-pull equipment.
You need a photo of your chosen loco since details varied over time and between batches.

I chose to model 7668 from the final batch (original No.16751 of 1931) which were the only 3F tanks constructed in LMS workshops (the ex-L&YR Horwich works).

The GRS Kit.

First observations:

1) The dome is too "flat" : The shape of the dome does vary from very "rounded" (in the Midland style) to a much flatter profile but the shape of the kit dome is far flatter than any photo I have seen.

2) The instructions state that the chimney is to be fitted over the centre of the smokebox : This is incorrect; it should be fitted centrally over the smokebox saddle, which places it to the rear section of the smokebox.

3) The brake shoes/blocks in the kit have a raised contact edge to the blocks which does not appear in prototype photos.

4) The sandbox castings have insufficient "taper" on the tapered edge.

5) The holes in the mainframes for attaching (all four) sandboxes are in the wrong places (the instructions give no indication for precise placement but measurements taken from a GA drawing indicate that the pre-drilled holes are against the very edges of the castings when placed on the frames.

Current state of (re-) construction.

1) Dome has been re-profiled by sanding and using Isopon filler to produce a more rounded top.

2) The brake blocks have had their "rims" removed.

3) The hornblocks and guides/keeps have been properly fitted using substituted 6BA cheesehead nuts and bolts (the original kit parts were 8BA cheeseheads which should have been screwed into the guides but the "botcher" had ruined the holes by drilling out and leaving no thread).
The reason he had done this was obvious : As is usual with GRS kits, the holes on the keeps did not align with the holes in the frames but instead of elongating the holes in the frames, he had drilled out the keep plates and used superglue to retain the bolts (leaving the keep plates loose and not parallel/flush with the frames)!

More will follow in a day or two!

John.

[John Candy]

Having further compared the kit body castings with photographs, a number of features caught my eye.

On the prototype, the smokebox saddle blends seamlessly with the smokebox wrapper but in the kit, there is a prominent joint, where the top of the saddle overlays the wrapper. A bead of filler was applied along the seam and sanded, leaving a seamless joint.

Another detail which is not quite right is the cylinder cover (the ledge which projects from the base of the smokebox front) : It should be more rounded in profile along the top edge. This was achieved by careful scraping and sanding in the restricted space beneath the smokebox.

The lowest gutter strips (just above the level of cab openings) are missing and were added from Microstrip.

Attention then turned to the chassis.

The sandboxes supplied are two pairs (LH & RH) of castings of identical profile.
If you examine photos of these locos you will see that the angle of the taper is not right and that, on the locos with the tank side cutouts for the fillers, the front and rear boxes are different from one another in shape (as well as the height at which they are mounted).

An approximation of angles and size had to be calculated from the available drawing (as is usual, minor details are not dimensioned on the GA drawing), as well as the positioning on the mainframes.
The castings were reshaped, as shown in sketches, by cutting through with a razor saw using a coarse (24tpi) blade and finishing with a file.

The locations on the frames were then marked  (the accompanying sketch shows the measurements deduced from the GA drawing).
New holes to accept screws for fixing the sandboxes in the correct locations are then drilled in the main frames (when marking and drilling the front set be careful the screws will not obstruct the movement of the compensation beams).

The front sandboxes will now obscure the heads of the bolts which act as pivots for the compensation beams, so it is necessary to assemble the beams before screwing the front sandboxes in position. The back faces of the two forward sandboxes will need to be drilled/countersunk to provide clearance over the pivot bolts referred to above.
The original screw holes provided by GRS can then be filled with Isopon, if they are visible along the edges of the mounted sandboxes

The brake pull rods (although not to be fitted until much later in the construction) require some thought at this stage : The rearmost pivot points are located on brass etched brackets which need to be attached to the steel mainframes. Once the driving wheels and motor/gearbox have been fitted, it might be unwise to bring a microflame butane torch (or heavy-duty soldering iron) too close in order to fix these brackets, so the wheels and brakes were fitted to the assembled frames and the location of the brackets marked on the frames. The wheels, etc. were then removed and the brackets soldered to the frames.

Some photos. to show progress will follow with the next update, in a day or two.

John.

[John Candy]

Sitting for well over a year, glaring at me from the corner of the work bench, has been the partly constructed GRS kit of the LMS 3F 0-6-0T ("Jinty").

I completed the chassis and started work on correcting the body faults but then shelved project in favour of other, more pressing, matters (e.g. the track around the garden).

Yesterday, I dragged the hulk into the operating theatre and resumed plastic surgery!

First to be removed were the tank fillers .... wrong shape..... and replaced them with my own resin castings.
Next, the front boiler band was pared and sanded away .... it was much thinner than the other bands and did not even have straight/parallel edges!

The boiler washout covers (on the shoulders of the firebox) were removed and replaced with the "plug" type (this was not a fault with the kit....simply that my loco is from the Horwich-built final (1931) batch which were built with the more modern plugs).

I then turned attention to the tank fronts, to drill for the handrail knobs and steps. Having marked out the handrails, it became obvious that there was a problem with the lubricator boxes. The handrail was almost touching the boxes, whereas photos show plenty of space between the two.

Measuring from the GA (in the Wild Swan Locomotive Profiles No.14) it exposed the model as having them 4.5mm too close to the edge of the tank.
Out came the razor saw and they were lopped off in a couple of minutes.

More reports from "theatre" before long ... I am determined to get this loco completed within a few weeks!

John.

P.S. Before anyone says I am being too fussy, let me say that, whereas I accept that there have to be compromises with the mechanical parts of models (just to make everything fit and work), it does annoy me to find errors and sloppy workmanship on the "cosmetic" parts ..... although, if you are working from a Skinley or Roche drawing, you are probably onto a "loser" before you start.

[John Candy]

Having already removed the boiler band forward of the dome, I then became suspicious of the positioning of the band to the rear (in photos the band appeared much closer to the dome than on the model casting).
Sure enough, taking a measurement from the GA showed it to be in the wrong place!
Off it came!

The next disappointment was to find that the tank front steps (etched brass) were over-sized and the wrong shape!

The steps needed to be reduced by 2mm in width (1mm each side to maintain correct relative position of rivet holes) and the fixing flange reduced by 1mm in height, with the corners rounded off.

The lubricator oilboxes were refitted to the tanks, together with the steps.

Next the lubricator pipes and handrails were fitted.

Next job will be to attack the tanks with the hair-dryer .... to correct a slight "twist" in the castings.

I do often wonder whether it wouldn't be quicker/easier to scratchbuild than to wrestle with some of the kits I have constructed!
In this case, I do think it would have been quicker to have thrown the boiler/smokebox casting into the bin and have started from scratch, rather than spend hours, scraping, filing, filling and sanding before making replacement details.

More (hopefully better) news soon.

John.

[Geoff Nicholls]

I've used boiling water, or steam from a boiling kettle, but never thought of using a hair dryer, to reshape resin castings. Does it need to be a really powerful one?
And could that technique be used to form a carriage tumblehome? If you have, say, a 3mm thick carriage side fastened to a former, could you just wave the dryer at it until the lower half gently settles on the former?

[John Candy]

Geoff,

I have used the hair-dryer to straighten parts on other GRS kits.
For thin resin it should heat up sufficiently very quickly (I have used the technique on quite thick lumps but then it takes a while to heat through).

John.

[blagdon]

John, Mrs Pirate has just commented' why does he keep on buying this manufacturers products if he only then proceeds to write disgruntling articles about them.'

The Pirate on behalf of Mrs Pirate {herself a G3Soc member}

[John Candy]

Good question!

I suppose I hope the next one can only be better than the one preceding it.

In the case of the 3F, it was not bought directly, but obtained as part of an exchange deal involving disposal of an unbuilt "brass bugger" (for those unfamiliar with the expression, that's Ian the Pirate's nickname for the GWR 2021 class kit)!!

John.

[Traininvain]

Keep writing 'em John. They are of immense value to all those people who want to build a similar kit.

Full report for the G3 newsletter please.

Many tx

Ian

[John Candy]

Ian,

Yes, it should be ready for the Summer issue, so reserve 2 or 3 pages.

A word of caution to anyone in the process of building (or about to commence) one of these kits.........DO NOT place fittings (e.g. tank top fitments, whistle, etc.) as shown in the illustrations provided with the instructions.

They are not in the correct positions and appear to have been placed in haphazard fashion!

I will provide dimensioned sketches taken from the Derby GA drawings.

John.

[John Candy]

A case of one step forward followed by two back!

In the thread on the Johnson 1F, Andy warned me that the buffer beams on that kit were too deep.
Having guillotined the 1F parts to correct dimensions, I then wondered about the 3F.

Sure enough, the 3F parts were oversize by the same amount as the 1F.

I had assembled the 3F chassis and running plate a year or more ago, so the buffer beams were removed.

The 3F kit has thick steel backing plates to brass overlays (unlike the 1F which has two thin nickel silver parts which are spaced apart) so the steel plates were sawn and filed, while the overlays were able to be guillotined (the strip should be removed from the bottom edge of the beams).

(Note:The brass overlays have rivet punching marks etched on the reverse and this resizing will remove the lower row. However, photos show only limited riveting on most of these locos and very few having a row along top or bottom. In fact, most have no visible rivets at all, they must be either countersunk/flush or welded).

The running plate valances then had to have the "drop end" sections cut/filed back to match the buffer beams.

Then the steel main frames had to be re-profiled at each end to match the reduced depth (if your motor is fitted when you carry this out, I suggest wrapping it with masking tape to keep the filings from attaching themselves to the magnet....or worse, getting inside the motor through vent slits).

Next the bases of the buffer guides were reduced by 1.15mm on all sides : The buffers are overscale in diameter as well as the bases but but there is not enough brass to skim them down, so I will just have to live with that.

The buffers then needed to be elevated on the beams and this was done by elongating the holes and then (to stop them dropping down) adding a small amount of "packing" to the underside of the buffer screw thread, where it fits through the beam.

Beams and buffers re-attached.....and we are back where we started!

[John Candy]

The past week has seen a blitz on the 3F, which has brought it close to completion.

First to be tackled was the brake rigging, a fiddly job but it did not raise any issues and went together well.
Unlike the 1F kit, which has nice turned steel cross-shafts with threaded ends, the 3F involved cutting lengths of wire and brass tube to fabricate the shafts.
The ends of the lengths of wire need to be threaded 10BA, so you will need a 10BA die and holder, an item not listed in the "Tools Required" section of the instructions.

The only parts remaining to be fitted to the chassis are the sanding pipes (left until last since vulnerable to damage) and the wheel balance weights (not supplied with the kit and will be cut from plastic card).

The next issue was the steps which give access to the sand fillers (just ahead of the side tanks).
The etched parts suppled are the wrong shape (see photo.) and new steps were fabricated from brass.
A general point to note when dealing with the running plate steps : As built, the early batches had "flat" treads but later batches had the sides turned upwards to prevent slipping. A few early locos. had the flat type replaced with the later type but the majority simply had their corners bent up. You will need a photo of your chosen loco. to be sure of getting it right.



The brass castings supplied are very nice : The whistle, tank water gauge and brake handle are excellent.



However, before you get too excited about the rather nicely cast vacuum ejector, let me point out that it is the wrong shape!
If you don't mind, then just fit it but it would have glared out at me every time I looked at it.
It was dissected (as shown in the photo). filed to shape, then drilled and reassembled with new connecting pipework.





It should be noted that the brake handle (which protrudes into the cab from a ledge on the front of the bunker) is angled forwards into the cab, to match the angle of the (concealed) shaft/column which links it to the crank on the cross-shaft beneath the bunker.

The only supplied parts now causing concern are the cast resin splashers ... they appear to be less "rounded" than they should be and will be reprofiled with sheet metal.



All the major modifications have been completed on the superstructure and it is now ready for final assembly.

[Geoff Nicholls]

you mention using a 10BA die to put a thread on the length of wire. I've never seen this done. Is it straightforward? Could it be done by a kitchen table modeller?
Is it the sort of thing that could be videoed and posted on G3madesimple?
As an alternative: I used brass tube with brass screws soldered in the ends for a similar purpose. I was expecting to need to file down the thread to squeeze it into the tube, but the tube expanded when the heat was applied so I didn't need to. It was just a case of choosing the right inside diameter tube.

[John Candy]

Geoff,

It is not difficult, you need a vice (a small hand-held type would do to spare the kitchen table from a heavy-weight) to grip the wire and then you simply screw the die onto the wire.....not much more difficult than threading a nut.

John.

[John Candy]

One small detail missing from the kit is the front sandbox fillers .... there were none in the box and they are not listed on the "contents" page of the instructions.

It should be noted that these fillers are not circular but oval in shape.
As built, the locos had filler caps with a knob to aid removal for filling.
Later, some locos received a different, replacement, pattern with the hand holds recessed into the cap.

To make the caps, I cut two 1.6mm deep rings from 1/4 inch brass tube and "squeezed" gently to an oval shape.
I then filled the rings with solder and filed the solder flat on both surfaces (also take the sharp "edge" off the top perimeter of each ring with a pass of a fine file).

Next came the question of how to deal with the lifting knob.

First thoughts were to fit a handrail knob but these are much too large (unless you happen to have an "0" gauge example in the scrap box).

This where the decades old habit of hoarding seemingly useless items pays off!

In the "good old days" (before political correctness and the H&S nonsense which sees warnings that knives can cut and lawyers lurking behind every hedge, waiting to jump out with a compenstion claim form)  when Marks & Spencer used the "St. Michael" brand name on their clothing and their shirts were packed with steel pins (WARNING : Pins are sharp!) you may remember that those pins had their "heads" encapsulated in a "blob" of (what appears to be) solder.
Well, I knew they would be useful one day and, sure enough, they were just what I needed. A hole was drilled through the centre of the filler caps and the pins glued in place.

John.