A RETURN TO THE WORKSHOP 
PART 5
BY JOURNEYMAN


BY THE TIME you read this the deep freeze will be over, although the forecasters are talking about it continuing into the New Year, heaven forbid. Here in the Styx we have had no more than an inch of snow altogether, but consistently much lower temperatures than the weather maps have shown. It’s very hilly round here so even with a 4wd vehicle great care must be taken. I know of at least one model engineer (not my mentor) whose workshop was several feet deep in snow, no lathe work for him for a while, unless he is determined with a shovel.

Freezing cold equipment is a real problem when it starts to warm up. The faster it does, the more the condensation gathers. In the forge I used to drape my equipment and my anvil and hammers in loads of old blankets and curtains to slow down temperature changes both down and up. An anvil covered in moisture is a bit crackly when you hammer hot iron on it and is a big lump of metal to warm up in a freezing building. It was not kept cosy overnight just because I loved it!


Post script

In looking for a piece of metal in the forge recently I came across one of the hot- punched elements that were described in Styx 4 which was never used. I think it was the initial test piece which I didn’t use. It shows the finished shape before the ends were forged down to the ¾in. square section for welding onto the bars. The hole is 1 ½in. diameter.

    

Boxhill

I am working on the valve gear and reversing assemblies at present. Am I the only person to find all this tricky? It’s not so much the making of  the individual parts as knowing the precise relationships of  one part to another and then the next one again, and so on.

I found a need to look into the setting of the valves because this is influenced by dimensions from the crank axle right through to the valve itself, or so it seemed to me, and here Martin Evans was not very helpful. Also, I was working with parts, some of which were made many years ago, such as the motion plate and found that the centre lines of the valve spindle guides, and therefore the spindles themselves, did not line up with those of the valve rods.

Where the errors were I couldn’t easily see, they could also have been in the cylinder block and valve chest, although I was very careful with these. Also, I shall have to remake the expansion links and die blocks with gauge plate and by machining methods, to replace the old mild steel ones with which were made by filing.

Other parts such as the slide bar clearances had comparable errors so I decided to go down the route of adjusting by filing and shimming to have all the parts of the assembly in a free running relationship to each other in all three axes, with special attention paid to the axial play of the crank axle. While this may sound all rather hit and miss, the adjustments were not very large,  mostly only a few thou.

The job that is yet to come is the offsets specified for the eccentric rods. Dimensions for these are in the drawings, but I think it will be a matter of a little at a time, assembling, sighting along the lines, and watching the movements of the parts while turning the driving wheels by hand initially, and later using air pressure.

Endless hours in the forge straightening bars for gates trained my eye to spot very small deviations from a straight line, as little as 1/32in. over 6 feet, and this skill has been useful all through this project, so watching for misalignment will be as easy for me as trying to do the job by micro-measurement.

Guidance and help has once again come from my mentor who gave me instructions, calculations and drawings for a jig to set the eccentrics accurately relative to the cranks, and a neat way to adjust the valve rods longitudinally in very small increments where they are secured to the valve spindles.

The calculations are always my bugbear, I have no experience of approaching these situations mathematically so it is really helpful to be shown how. Such ‘sums’ were not needed in the forge. For example, to space the bars on a gate I simply used dividers and ‘walked’ them along the rail, making repeated adjustments until a whole number of spaces (paces?) spanned the distance between the first and last marks. I never was asked to build a spiral staircase!

Setting the offsets on the reversing lever stand and the lever was a matter of care in marking the points at which the bends began. I used a black felt tip pen for this, marking the starting points of the bends directly off the drawings, and then gripped a bar of suitable diameter against the part in the vice and, holding a piece of copper against the steel gently hammered in the bend round the bar, checking frequently against the drawing until it was bent enough. Once again my blacksmithing experience was a great help with these operations.

Talking of forges, Bryan Young’s model in MEWS in December was fun to see and what a lot of well observed detail, and so CLEAN, not a speck of soot in sight! One thing though, is his blacksmith left-handed ? If not , then the anvil is the wrong way round, and a bit far from the forge.


Back numbers

A couple of years ago I acquired 80 volumes of back numbers of Model Engineer Magazine, thereby at a stroke replacing all my own volumes that I had sold some years earlier. I decided to look through them all, bit by bit and compile an index of everything of interest that caught my eye, as I had done many years earlier.

It’s been a lot of fun and interesting to see how the magazine has changed over the years. In 1944 it carried ads for new lathes which you could buy only if it was for war work, and editorials expressed complete confidence that the Allies would win the War. Gone now are the numerous articles on power boats and flash steam, and there seem to be fewer items on i/c engines. However, interest in steam locomotives, stationary steam and traction engines is as strong as ever, as is interest in boiler making. In this last topic the experts have always insisted that it is not as difficult as people fear so long as you pack the work round with asbestos blocks! (NEVER now, very dangerous),  proceed with care and have PLENTY of heat, oh and beware the pickling acid! The boilermaking feature in MEWS w/e 14 Feb will be very useful for Boxhill’s boiler.

Certain topics come round at regular intervals such as articles and series for beginners, including the ubiquitous Stuart 10 models, one series by Tubal Cain in 1982 telling how to build a 10H using only hand tools, but the ‘Duplexes’ and ‘Tubal Cains’ and ‘Jeynes’s’ seem to be characters of the past, to be replaced by regular contributors such as Dave Fenner and Harold Hall and others. “How to build a dividing head for the _______ lathe “ was quite frequent, as were milling attachments, and the preoccupation with the merits or otherwise of superheating continues unabated. Here on MEWS we have our own Artisan to provide ‘shop wisdom’.

There are 100s of ideas for workshop tooling, continuing to this day, and some truly off-beat

things people have done. If you want to know how to secure your loco firebox stays with Araldite go to 3 September 1976, p.867.  Apparently it was very successful!

Also go to  7 May 1982 p.551 to find out how to machine a watch hand measuring 0.240 long x 0.025 x 0.007in.  under the title of  ‘The Challenge of Being a Model Engineer’. W.S. Steer decided that it was no more difficult than doing one ten times larger. He only had to work out a sequence, and after two weeks preparation including making a diamond point drill 0.017in. dia., and a 0.010in. dia. milling cutter, the job took a mere hour in the making; amazing, and a perfect illustration of the kind of inventive ‘working out’ that I am increasingly enjoying in my own work, and what made Britain GREAT.

We often see reports on assemblies of model traction engines going on road runs, but in 1990 the Bedford MES decide to put some to work. They had to dismantle their old track in preparation for building a new one. Several owners of larger scale models were invited to help demolish the old concrete piers which they did very successfully, see ME 16 Nov 1990, an event with a difference.

Four other notable features stand out.  J.N. Maskeleyne’s superb drawings in “Locomotives I Have Known” from 1956-61, the continuing success of IMLEC, reviews of new products for sale, and Model Engineer Exhibition reports. This annual event, together with club and other national exhibitions and rallies, shows that the hobby is as alive and vibrant as ever, although it is a pity that MEX is not supported enough by both exhibitors or the Trade compared with the other major exhibitions.

The greatest change is the introduction of computer controlled drawing, design and machining into the hobby. This is both for the individual, and firms using it to offer kits and finished models at affordable prices. Laser cut parts are also gaining in popularity. None of this appeals to me as the process of using my hands with both hand and machine tools is where I gain my satisfaction. However, for the new enthusiast starting up after retirement they must be a godsend – the time left to those of us who are pensioners seems alarmingly short.

Model engineering in the Styx -
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Hot punched hole

Correcting bend on reversing lever

Correcting over-bend on reversing lever

Setting bend on reversing lever