Daifly's Workbench - A First 7mm Loco Build.

daifly

Western Thunderer
Persuaded yesterday by the Bath Bookseller to build one of my collection of kits, I chose the Agenoria kit of the ex-Cambrian 2-4-0s nos. 1192/6/7. All 3 locos all can be constructed form the kit in their GWR rebuilt form with most of the detail variances catered for. Since 1192 was withdrawn in 1929 and 1196/7 both lasted until 1948, I arbitrarily selected 1196 to be the subject of this build. I have a second identical kit which will become 1197.
The instructions begin with assembly of the cab and tanks, but my preference is to first build a running chassis. Almost immediately I hit on a snag. This is my first loco build since moving up from 4mm EM gauge and I found that the instruction to ‘ream out the axle holes’ required a considerably bigger broach/reamer than anything that I had in the toolbox. The old, crude standby of the tang of a file did the job but I bought a taper reamer from Squires today from their stand at Swindon ‘Steam’ exhibition so future builds will be easier.
Incidentally this is a particularly good show with substantial content of 7mm layouts and exhibitors including Pete Waterman assembling a JLTRT ‘Bloater’ and David White (of Slater’s) getting into a pickle building a bogie by ignoring the assembly instructions what he wrote and finding that he had bits of brake gear left over which could not be fitted at a late stage!
The chassis is built up using tab and slot spacers. Most of the slots needed opening up using a screwdriver blade to remove the cusp from the etched slots which stopped the tabs entering. A number of tabs were slightly too long but a couple of strokes of a file reduced their length to fit. A number of holes were drilled out in the chassis sides ready to accept wires representing bolts or to hold the brake assemblies.
Time to fire up the RSU tomorrow. Photos and more to follow.
 

daifly

Western Thunderer
All of the above - and others too! The Tanat Valley locos were all very attractive IMHO. I have several of the kits to build that Pete Stamper produced when he owned Agenoria.
 

Simon

Flying Squad
That's a really attractive loco to start with, I'm flattered to think that I might have helped you to make a start:oops:

Quiet day in the shop yesterday so I set to and rebuilt the display shelves so that the buses can move down from the top shelf and a bit more stock can be fitted in.

I look forward to seeing the pictures, a 2-4-0, what a good idea.............

Simon

in da kitchen
 

daifly

Western Thunderer
That's a really attractive loco to start with, I'm flattered to think that I might have helped you to make a start

Quiet day in the shop yesterday so I set to and rebuilt the display shelves so that the buses can move down from the top shelf and a bit more stock can be fitted in.
Of course, if I run into problems, it will be your fault!

Glad to hear that you have overcome your 'shelf inertia'.

Dave
 

daifly

Western Thunderer
Fitted at the same time as the n/s L-shaped chassis spacers is a brass piece forming the front of the cylinders. This needed the half-etched rivets pressing out. I used a simple tool bought many years ago. With the test piece on the cutting mat, a little trial and error established how far up the rod the bob weight needed to be lifted to produce the required impression.

DSC02544s.jpg
Time for a dry run in the Masterchassis jig. There are four spacers plus the cylinder front tucked under the front spacer. One of the spacers has had a bridge piece and 6BA nut soldered in place ready for the front pair of wheels which are arranged as a bogie.
DSC02550s.jpg
With only two coupled axles, the rods will be made to fit the chassis rather than the other way around.
My apologies to those of you for whom this thread is a little condescending but I'm exploring a lot of new tools and techniques. Some of it may be of interest to other newcomers to the scale. I've elected to build this kit 'out of the box' so no compensation, split axles or other 'clever' stuff. One step at a time.

Dave
 

Buckjumper

Flying Squad
The locos pete Stamper designed for Agenoria go together quite nicely - I can't foresee you having any problems with it.

Laurie Griffin has made an interesting amendment to his HH chassis jig and details it in the latest MRJ. If you have - or know someone who has - access to a lathe then you might find it worth a read.
 

Steph Dale

Western Thunderer
Dave,

Two quick pointers to help refine your technique. On the assumption you find such things helpful rather than irritating ...

1. To open out any location slots use a piece of scrap fret rather than a screwdriver. That way you'll make best use of any accuracy in the parts and reduce the risk of creasing anything.
2. The top nuts on your (LRM/Foutrack) 'drop riveter' can be undone and moved to the height position you like - this will give you nice uniform rivets, rather than using a piece of tape to mark it; I suspect this is why the thing is made on a length of studding. Incidentally, if you use something firmer than a cutting mat you'll get a better shape and definition to the rivets - a pice of MDF or lead sheet used to work well for me.

Steph
 

daifly

Western Thunderer
Good progress. The chassis has been soldered up, excess tab lengths removed and wheels fitted. There's a little bit of excess sideplay on the drivers which I will eliminate by fitting washers. The photo shows the front bogie assembled and ready to fit. The little tray on top of the bogie is to hold a supplied whitemetal weight.
DSC02551s.jpg
Having fitted the bogie, it obviously has no sense of direction and will benefit from some form of springing to keep itself centred and give guidance to the coupled wheels when running forwards. That's something to tackle tomorrow - so much for building straight 'out-of-the-box'! Fitting the motor, coupling rods, brake gear and pickups will be the next tasks.
This is where I am for today:
DSC02552s.jpg
Cheers

Dave
 

daifly

Western Thunderer
Did the real thing have a bogie or is it just to help it get round curves?
It is a kit artifice to allow it to negotiate sharp curves - as low as 2ft according to the instructions. I will look at fitting hornblocks and 'fixing' the axle as I don't propose to utilise radii as severe as that.
 

28ten

Guv'nor
It is a kit artifice to allow it to negotiate sharp curves - as low as 2ft according to the instructions. I will look at fitting hornblocks and 'fixing' the axle as I don't propose to utilise radii as severe as that.
I guessed as much, but I havent looked at the prototype in detail for 20 odd years. It should be pretty simple to fit hornblocks, I take it that the loco will be finished in green although the really early version in Cambrian livery would be a nice choice, iirc there was a very flimsy looking cab roof on the very earliest version
 

daifly

Western Thunderer
The kit is designed around the GWR rebuilt versions so I'll stick with that rather than getting too ambitious. There are plenty of photos of the rebuilt locos and although I, too, like the Cambrian livery, this one is going to be green.
 

daifly

Western Thunderer
Modest progress. Coupling rods assembled from laminations, motor and fold-up gearbox installed, crankpins and rods fitted and, to my surprise and delight, the whole thing runs quite sweetly.
The kit contained a duplicate set of etchings for the front bogie so I made up the second one and this time ignored the bit in the instructions suggesting that material is removed to allow more bogie sideplay. I should have tried it more carefully the first time. The bogie now has a maximum of about 1mm lateral movement either side of centre before the bogie frame contacts the inside of the loco sideframe. This avoids the wheels themselves touching the loco frames while retaining the ability to negotiate fairly tight curves.
DSC02553p.jpg
Fitting out the chassis with pickups, brakegear etc. is next on the agenda.
 

daifly

Western Thunderer
Pickups and sundry other chassis parts have been fitted and now a score or more of brake parts have been fettled, laminated, drilled and broached to fit. I've reached the point where the brake gear needs to be fitted and soldered in place. The brake pull rods lie outside the driving wheels thereby making future disassembly of the chassis tricky without resorting to unsoldering the whole lot. Those of you who normally fit drop-out hornblocks with screwed keepers are probably feeling very smug at this point!
There are five crossshafts of 0.9mm brass rod, all of which pass through holes on the sideframes. I am considering assembling and soldering the whole lot except to the sideframes. Cutting the five crossshafts will allow the two halves of the brake assembly to be withdrawn thus allowing wheels etc to be removed if required. To hold the two halves together and with no lateral movement, I thought of stripping insulation from some appropriately-sized black wire. This would allow lengths equivalent to the between-sideframes spacing to be used to insert the cut crossshafts into. Before I go down this road, has anyone tried this before, got any comments on the idea or got a better solution please?

Cheers

Dave
 

Steph Dale

Western Thunderer
Dave,

I normally do this to make brake gear removable:
1. Fit the brackets/wire to the chassis for the hangers.
2. Use short lengths of micro-bore tubing as spacers (you could also wind copper wire around) on your brackets/wire. The lengths are whatever is necessary to space the shoe and hanger out from the frame and align it with the wheel tread.
3. Solder up the pull rods away from the chassis.
4. Thread the shoes/hangers on to the pull rods and brackets/wire. Then position and solder thr hangers/shoes on to the pull rods only.
5. Trim off excess brackets/wire from face of hanger (and also between frames, if necessary).
6. The brake gear can now be un-pinged from the hangers.

This sequence of pages from my website may help: http://www.euram-online.co.uk/railways/0gauge/secrl/ltender01.htm

Tha'sit...

Steph
 

daifly

Western Thunderer
Thanks Steph. That looks like a much better-engineered solution than the one I got from the Blue Peter book of kit building! I'll crack on with it over the weekend, I hope.

Cheers

Dave
 

daifly

Western Thunderer
Following along the lines of Steph's methodology, I have completed the brake gear. As a slight variation, I fixed the spacers etc to the stubs at the top of the hangers. I'm very happy with the result. Many thanks, Steph.
The chassis has been reassembled sans motor to ensure that the brake gear can be removed and refitted OK - it can!
DSC02557s.jpg

And with the brake gear removed showing (I hope!) what Steph described - no fewer than 26 individual bits in this:
DSC02563s.jpg
Just need to check that the pickups do and then it's time to start on the body.

Dave
 
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