TFW’s workshop

[richard i]

Thank you, you made me laugh.”quite fiddlly” in 4mm it would send me nuts, this is 2mm. All my hats have been taken off for the skill you are putting in to this. If my 4mm version photographs half as well I will be a happy camper. 

Richard

[65179]

15 hours ago, CF MRC said:

I have continued filling in the valve gear and drain cocks / linkage and cylinder covers. Quite fiddly. 

The nearside works plate will need a slight trim with a sharp chisel. 

Tim

Hi Tim, 

 

I'm pretty sure the drain clock linkages are beyond my skill level, but what effect do they have on the ability of Valour to go round corners. Do you get any shorting?

 

That front end now looks very much a B3!

 

Simon

[CF MRC]

The drain cock linkage from the cab at the front end was simply bent up from thin strip and soldered in place using the etched hole in the frames to locate the transverse rocker, Simon.  The drain cocks were another piece of bent up strip.   Shorting is not a problem because of split frame construction and the engine has no problems on my test track.  We’ll try her out on CF next weekend.

 

I will probably make the frame extensions in front of the cylinders from black styrene sheet as I can’t be bothered trying to make them from metal & insulated from the buffer beam etc.  The guard irons will be soldered to the buffer beam, but maybe onto a thin strip of intermediate PCB to insulate them from the body. 

 

Tim

Edited September 30, 2019 by CF MRC
Adding photos

[CF MRC]

I couldn’t go for much longer with Valour looking like a fire less engine so I have made the chimney and dome. 
A sketch is made of the critical dimensions (from works drawings) and then a piece of brass roughed out to this size with a correct diameter hole down the middle.  The rough shape was introduced using a graver by hand, rather like wood turning. 

The smoother curves were made using a fine round file.  Note the little finger rest upon the tool rest and the file held with a light pen grip. 

The shape was checked against the drawing and photos. 

The underside of the chimney was left overlong, on parting off, so that the smoke box shape could be ground into it.  What this was nearly correct the chimney was rubbed up and down some Micro Mesh abrasive cloth at the correct diameter on a rod to develop a good seating for the fitting. 

This then leaves a boiler fitting with ‘padded shoulders’.  

These were ground off using a pink stone in my Dremel-like hand piece and fine files / abrasives. 

The chimney and dome are both ‘full fat’ Robinson fittings with some quite interesting curves. 

Valour is now looking much better balanced, but of course the fitting that will make a huge difference will be the smokebox door. 

There are many ways of making boiler fittings, but this is the way I have preferred to make them rather than the ‘thinning the base and bashing technique’ favoured by some. 
Tim

 

 

 

[Nig H]

15 hours ago, CF MRC said:

I couldn’t go for much longer with Valour looking like a fire less engine so I have made the chimney and dome. 
A sketch is made of the critical dimensions (from works drawings) and then a piece of brass roughed out to this size with a correct diameter hole down the middle.  The rough shape was introduced using a graver by hand, rather like wood turning. 
 

The smoother curves were made using a fine round file.  Note the little finger rest upon the tool rest and the file held with a light pen grip. 
 

The shape was checked against the drawing and photos. 
 

The underside of the chimney was left overlong, on parting off, so that the smoke box shape could be ground into it.  What this was nearly correct the chimney was rubbed up and down some Micro Mesh abrasive cloth at the correct diameter on a rod to develop a good seating for the fitting. 
 

This then leaves a boiler fitting with ‘padded shoulders’.  

 

These were ground off using a pink stone in my Dremel-like hand piece and fine files / abrasives. 
 

The chimney and dome are both ‘full fat’ Robinson fittings with some quite interesting curves. 

Valour is now looking much better balanced, but of course the fitting that will make a huge difference will be the smokebox door. 
 

There are many ways of making boiler fittings, but this is the way I have preferred to make them rather than the ‘thinning the base and bashing technique’ favoured by some. 
Tim

 

 

 

Hi Tim,

 

Thanks for your description of how you made your chimney. I've learnt much from your informative and inspirational posts. I'm relieved that the techniques you use to make a chimney are not so far from what I do. I learnt from Mike Raithby, and he knew what he was doing too. I hope you don't mind me adding a couple of comments to your post.

 

I go along with checking the turning against a scale drawing and sometimes I've tried to get a near to 2mm scale version of the drawing to hold behind the turning in the lathe to check the turned shape looks about right. In our scale it's not so easy to measure any but the most significant dimensions of a chimney even if they are given on a works drawing. Once I've finished the overall shape of the chimney, I usually polish the turning in the lathe with fine wet and dry paper, then a glass fibre brush. I too part of with an overlong underside. I then start the smoke box shape with various oval profile needle files, holding the chimney (or as here, a dome) upside down between two cut-offs from pieces of rocket firework stick, as shown below.

 

 

You can see that the edges of the remaining flat section are curved. That is because the filed away section rises up in the centre of the turning and falls away again to the far edge. This has happened because of the see-sawing motion of the file and needs to be corrected so that the curves become straight lines, parallel to each other. This view also suggests that the curve is fairly central and if maintained, will avoid the chimney being lopsided on the smokebox as viewed front on. If the sides of the curved section narrowed towards one edge of the circumference, this would result in the chimney leaning front or backwards as viewed side on. When the front and rear edges are within about half a millimetre of the curved base, I use various grades of wet and dry wrapped round brass tube of slightly smaller diameter than the smokebox to finish forming the curve, as below (apologies for the blurred image, but I hope you get the idea).

 

 

As for the remaining padded shoulders, I use round and oval profile needle files to remove it and blend the curves round the base of the chimney before finishing it all off with fine wet and dry. I find this last bit really satisfying.

 

As regards fixing to the smokebox, I always epoxy in place so I have time to check the alignment and make small adjustments as necessary.

 

Nig H

[Caley Jim]

I employ very similar methods except, through not having the luxury of a lathe, I do the turning with my trusty old Black and Decker sitting on my knee!   I start the curving of the underside by making a cut with a piercing saw across the middle of the base, then open this up with a triangular file followed by a half round one in order to try and keep it central and level.  To attach them I first tin both the location on the boiler/smokebox and the underside of the fitting and then use low melt solder, but with the iron at a high temperature, to fix them.

 

It won't be long before I'll be turning my attention to the boiler fittings for my Jubilee pug.

 

Jim 

Edited October 3, 2019 by Caley Jim
Edited for the usual predictive text errors!

[Nick Mitchell]

 

3 hours ago, Nig H said:

I learnt from Mike Raithby, and he knew what he was doing too.

 

Well I learnt from you Nigel, so I guess I have Mike to thank as well!

A couple of years ago I posted this video showing the process of making a dome using my watchmakers lathe: https://youtu.be/l4u1OauT-u0

 

[Jim T]

What lathe are you using there Nick? Looks a fabulous little tool...

 

Jim

[Nick Mitchell]

20 hours ago, Jim T said:

What lathe are you using there Nick? Looks a fabulous little tool...

 

Jim

Hi Jim,

It is a "Sincere" Geneva pattern 8mm watcmaker's lathe from China.

I've had it about 10 years, though they are still readily available alongside a whole bunch of accessories on eBay.

The threads of the collets are metric rather than WW, but a WW threaded drawbar is available to use with other fittings.

The basic model is around £700, but other packages with various accessories included come and go from time to time.

I believe it is a rough-finished out of the back door of the factory version of the Vector lathe, which retails for several times the price.

https://www.ebay.co.uk/itm/1Set-Brand-New-Watchmakers-Precision-Lathe-Basic-Machine-New-Free-Shipping/362479888571?hash=item54657c28bb:g:pv0AAOSw~vNb4UgX

[CF MRC]

The GNR N2 failed to proceed on Copenhagen Fields at Fareham last weekend. It was made by the great Denys Brownlee and has run for 30 years, probably covering many hundred of real miles in that time.  

It is very rare for me to have two engines on the go at once, but I thought this deserved a ‘12 hour chassis’ - so it jumped the queue. 

 

On examination, I found that the 1/16” axles were worn by 0.1mm. 

They were put in a step collet and have been re-profiled to 1.5 mm diameter. 

On looking closer I also noted significant wear on the coupling rod pins.  Denys had used remarkably thin  (for him) steel for the rods and it had ‘cut in’.  The new rods will be made twice as thick. 

 

The chassis has been made with brass frames and tapped acetal spacer blocks.  The frames were separated from the blocks and one sweated to two pieces of brass to act as a pattern for the replacement chassis. 

 

The old holes were located using an equivalent size drill upside down as a plug fit in the drill press, with the frames held accurately in a vice on the X - Y table of my mill - drill.  Once the location was correct, the drill was used correct way up to make the hole.   The axle holes were drilled by dead reckoning, using the table to set the coupled wheelbase (the rods will be made the same way). 

Once all the holes were made, the new chassis was filed up to shape using the old one as a pattern: the image shows the three pieces still sweated together. 

I am fairly confident that I will be able to re-use some of Denys’ acetal spacers.  It would be appropriate to keep as much of the original as possible. 

 

Tim

 

 

 

Edited October 9, 2019 by CF MRC

[CF MRC]

The coupling rods were made from two quite thick steel blanks with the holes drilled by dead reckoning in the mill / drill.  These were soldered to a 1/2” x 1/6” thick steel strip, taking care to make sure that they were parallel with  one edge.  This was achieved by tinning the components, holding them in place with some clips and then using a miniature marking gauge to nudge them parallel with the edge.  A quick flash with the blow torch and liquid flux melted the solder to attach them to the brass. 

The area between the bearings was thinned down using the brass strip to hold the rods in the vice and then draw filed to make a flat surface.  The raised bearing areas help to stop the fluting extending. 

The flutes were made by using the same marking gauge, with the gramophone needle tip ground to a chisel shape for planing out the flute in the rods (which may have been how the originals were made). 

Once this was completed, the brass was reheated with the blow torch and the two, very wide, coupling rods removed. 

These were then reduced in height using drills through the rod holes to locate them in the vice.  I use my fingernail to act as a stop, against which the safe edge of the file will run, when filing the areas that are difficult to see

A ‘stop’ is filed into the steel and then the material in the middle can be easily removed, finishing off with draw filing. 

Final finishing includes filing in the oil caps and rounding off a few corners.  

The rods are a bit smaller than Denys’ ones, but the bearing surface is greater.  

 

I appreciate that this method was described when I was making Mons Meg, but the images in that thread will have disappeared with the demise of Tinypic, the image hosting software.   These rods didn’t take too long to make and steel rods are so much stronger than nickel silver. 

 

Tim

 

 

 

 

[CF MRC]

The N2 chassis was assembled, wheels quartered and after a few minor tweaks of the coupling rods it was sufficiently free turning to bond the motor gear box to the Tri-ang type cut outs in the frames with 24 hr epoxy adhesive.  The worm simply rests lightly on the worm wheel whilst the adhesive is curing. The motor casing had some insulating fag paper and 24hr epoxy wrapped onto the area that would be next to the frames, well ahead of final fixing to the chassis. 

It may seem sloppy practice to glue a motor in place, but there is no maintenance possible on the motor-gear box. If the worm wears then a sharp tap underneath with a screw driver will break the glue joint and the final drive gears can be replaced.  We have used this approach on quite a few of the tank engines on CF.  The engine hasn’t yet turned its wheels in anger with the new chassis (the adhesive is curing as I write this), but it should be alright.  More to the point, we will have had a replacement chassis made within a week of failure: there will probably have been a bit more than 12hrs work to get this chassis running, but that was mainly due to the need to make some fluted coupling rods. 

 

Tim

[chris p bacon]

I hope this doesn't sound like a stupid question....what actually holds the short stub axles in place ?  I realise they are for a split chassis but doesn't the gear bridge the break ?

[CF MRC]

Never a stupid question, Dave. The standard Association design is to use acetal muffs which are 1/8” diameter with a 1.5mm axle hole which accepts the stub axles as a force fit.  The picture below shows these on Mons Meg. 

The gear box on this engine is a bit special but normally the gear simply sits on the outside of the muff and so is insulated. 

 

Tim

Edited October 14, 2019 by CF MRC

[queensquare]

Great thread Tim. The making coupling rod sequence would make a great No.1 shop article........

 

Dave (Chris P), below is the underside of my Midland 1F showing the gear on muff arrangement. It also shows how the brake gear is electrically split by nipping a mm or so out of the center of the cross wires  and replacing with a bit of fine electrical sleeve and a spot of cyano. The cigarette paper and cyano insulating pads are also visible under the body.

 

 

Jerry

[chris p bacon]

Excellent, many thanks for that I now understand.     I am in awe of the craftsmanship shown in 2mm, I'll stop complaining about doing some simple phosphor bronze pick ups on a couple of 2-4-0's

[Caley Jim]

Chris, the beauty of the split frame system is that every wheel can be used for pick up, be they driving, carrying, bogie or tender, without any pickups acting as brakes on them.  

 

Jim 

[CF MRC]

The N2 now has a working chassis.  I have re-used the pick up arrangements off the trailing truck; consisting of re-curved 33SWG phosphor bronze spring to both centralise the truck and also transfer current to the chassis frames.  I think these wheels are an insulated type. 

The brake gear has also been re-fitted, although I probably won’t bother with the middle axle brake shoes as these are behind the steps (they do catch fluff).

The engine needs some detailing for its suburban working into KX, but it runs quite well and should be a useful stalwart again. 

Some videos of it working:

Tim
 

Edited October 14, 2019 by CF MRC
Adding videos

[CF MRC]

Back to working on Valour and the reversing rod and box have been fitted.  Quite straightforward use of the etch for this, although I replaced the reversing linkage box with a lump of brass.  It was easier to file it up from the solid rather than fiddle with the etching supplied in the kit.  It will be handy to have a removable boiler for painting as the linkage is tucked in very close. 

I have also turned up the smokebox door from nickel silver rod, so that the door sealing ring can be cleaned up as bright metal.   It may stay removable as it locates accurately with a spigot so that the sealing ring edge is nice and sharp.

 

I do like this stirring photo; it also shows a wonky buffer which Valour carried for quite a while. Shouldn’t be too difficult to mimic that!

 

Tim

 

[CF MRC]

Am I the only one that dislikes making tender & engine steps?  I have made them up from the etches, but the tender ones were a bit tricky because there is a curve / angled area above the top step.  

The etched top of the step was bent over and burnished to give a sharp bracket to solder to the tender body.

The tricky bit was that the change in angle occurs below that.  There seems to be variations in the tenders as to how pronounced this is, but in the self trimming tender it seems quite subtle.  Packing the top of the step above the vice and then bending over with a file, to exert an even pressure, produced a regular shape for all four steps. 

 

Soldering on the step bodies was straightforward.  The steps themselves were etched in the kit, but at 8 thou thick are over-scale and jolly fiddly to handle.  I therefore made new steps from 5 thou N/S strip.  The end was bent up at 90 degrees to solder to the backing plate and then the rough size of the step weakened in the strip with a pair of side cutters. 


The long strip was then much easier to hold in place whilst the soldering iron was bought in to flash the tinned joint.  After placement the fatigued/weakened area allows the holding piece to be snapped off the step.

On the engine cab steps, the design is slightly different with a groove or slot to hold the steps and so the individual steps were soldered into place directly, being held by some titanium tweezers that will not take up soft solder. 

The half etched back plate for the steps produced a rather weak structure and so a bracing bracket was sweated in behind, which is also prototypical. 

All OK in the end, but not my favourite job on an engine. 

 

Tim
 

[queensquare]

You're not alone Tim, steps are one of my least favourite jobs as well.

 

Jerry

[2mmMark]

2 hours ago, queensquare said:

You're not alone Tim, steps are one of my least favourite jobs as well.

 

Jerry

 

Apparently, it's worth persevering with them.

 

 

[65179]

Tim,

 

This comment won't do much to aid your love of doing steps, but can I ask have you taken account of the fact your tender valance is solid?  As someone who's spent too long looking at GC tenders the proportions of the steps don't look quite right.  Looking at your tender compared with Butler-Henderson's the top step seems to be lower than the adjacent buffing plate/bufferbeam whereas the top of the step and bottom of the plate/beam roughly line up on B-H.

https://en.m.wikipedia.org/wiki/GCR_Class_11F#/media/File%3ABarrow_Hill_-_Butler_Henderson_-_geograph.org.uk_-_2314614.jpg

 

It might just be the angle from which your photos are taken, in which case ignore me. However if there is a discrepancy that could be an etch error or it could be that if the etched stepplate was meant to fit behind the etched valance. 

 

I shall certainly be using your approach to strengthen steps by using a bracing bracket.  Thanks once again for sharing your build - it's so helpful seeing how the experts tackle things!

 

Thanks,

 

Simon

 

 

 

[CF MRC]

I couldn’t quite see what was wrong with them, but even before your post Simon, Tony Gee had put me wise to the problem with the steps.  The middle step should be upside down, with the support bracket underneath, not above.  That way it sits in next to the angled piece rather better.   Thirty minutes work to make and fit some new steps (I’ve got my eye in on this step making lark).

The  steps are a little short of the buffer beam at the back because there is no side upstand.

 

Tim

[t-b-g]

Sorted!

 

The proportions look right now.

 

I have just looked at mine and although I got it right on my 7mm model, my 4mm one has exactly the same fault and will need correcting!

 

I built the 7mm one first and knew how to do it so I have no sensible excuse ready.