If you do not like what I write then blame your Editor! However, I do aim to please so be assured. How did this all come about? Me from the North Midlands writing for you in glorious Somerset? Well, whilst visiting the Model Engineering Exhibition at Leamington I espied your Editor and Chairman, both 7 ¼” G. Society members. Now I have been known to write the odd diatribe haranguing 7 ¼” Society members to do something and your Editor possibly in a desperate attempt to gain more copy for “The Oily Rag” bent my ear - would I write something for the aforementioned journal. Being old and possibly a soft touch I agreed, so here you have it.

Who am I? My name is Alan Westby but known to all and sundry in the 7 ¼” G Society as “Mr.M.D.F.” and I live with my wife Valerie and dog Sami on the eastern outskirts of Nottingham with the Nottingham-Lincoln railway line at the bottom of the garden. Unfortunately little in the way of inspiration there. I am a retired schoolmaster having taught technical studies (woodwork, metalwork and technical drawing to you).

However, I spent many years in industry prior to entering the teaching profession and so I know life from both sides so as to speak. It is really from my industrial side that I would wish to write at the moment and maybe give you a little food for thought, with some devices etc. that may be new to you.

As I mentioned earlier, within the 7 ¼” G Society, I am known as “Mr.M.D.F.” M.D.F. – Medium Density Fibre Board. A most useful material if treated with care. Are you building a 3 ½” – 5” G. Loco and how do you set the frames up square and free from twist or wind? In an ideal world, you would have a Surface Plate or a marking-out table. LBSC used to recommend using the lathe bed but that is not always easy and if you have a Boxford, Harrison or similar lathe, perhaps impossible. Another good recommendation is a piece of thick plate glass but maybe not easy to acquire. When you remove the mirror from the wall you may get a few askance looks – “so and so bought us that” and if, perish the thought the hammer falls on it whilst you are engaged in your lawful pursuits, you’ll have more than a few years bad luck!

But a piece of M.D.F., 25mm thick can make a reasonable substitute provided it is treated fairly. Get it wet and the dustbin is the only place for it, but keep it dry and store it on end as near vertical as possible (to avoid sagging) and it may just get you out of a fix.

Are you thinking of building a copper boiler and need to consider flanging blocks? Forget the sweat and toil of hacking away at great lumps of rough steel plate – use some M.D.F.- 25mm is ample thickness for formers. If you can’t get 25mm, then glue thinner sections together using ordinary P.V.A. glue. To avoid it slipping and sliding all over, a couple of nails driven in it will halt its game whilst you cramp it up. Don’t knock the nails right in – you can remove them when the glue has set.

To cut formers out use a jigsaw as it is so much easier than slaving away with a hacksaw and quicker too. When you have finished your formers by whatever means you choose and you have doubts about the M.D.F. standing the strain of beating the copper over it, then reinforce the edge by giving it two or three coats of varnish or French polish as this will harden up the edges.

If you have read Steve Gosling on making the cab for his L.M.S. Compound, he has used M.D.F. with complete satisfaction.

The secret of success when flanging boiler or any other plates is to keep the metal annealed. When squaring up the ends of boiler barrels, M.D.F. is ideal for making discs to fit the bore. M.D.F. can be sawn, turned and sanded easily, but one stern word of warning, like smoking, M.D.F. dust can damage your health.

Can you saw straight and square? You can! Good fellow and you can skip this bit but if you cannot, do not despair, all is not lost. I used to say to the children that I taught when they first came into the workshop – “If you can saw one piece of wood square, you are lucky – if you can repeat the process then you are in the wrong class!”

A simple device pinched from the jewellery trade is shown in the sketch below.

The only requirement is that the internal sides must be square to the top and bottom faces. Make several different sizes for convenience of use – whilst it will not enable you to saw square, it will enable you to square up sawn ends without too much trouble. For long life the top should be faced with a metal cover which can be replaced when worn. In the jewellery trade they are much smaller and made of metal and are used for squaring off wire mouldings etc., to make butt joints.

To saw sheet metal to a straight line, it was often advised to scribe two lines a little over the saw cut width apart – a good idea and especially useful when cutting on the band saw, but try this. Clamp/cramp a straight edged piece exactly on the line of cut about ½” (12mm) thick. Lay a hacksaw blade along side and clamp/cramp a second piece to the same thus making a guide for the saw, Several small G cramps are useful adjuncts in the workshop and are cheap to buy at exhibitions.

I see that I have missed the date of the Club Auction. I wonder if any electric motors were for sale ? A quarter or one third horsepower motor – 1425 r.p.m. is a good basis for one of the most useful tools in the workshop, a disc sander. With this tool, squaring up or producing any angle required is child’s play.

To make a simple device, firstly ensure the armature shaft or spindle is in good order. You then require an aluminium casting similar to a faceplate about 6” diam and say 1/2” plus thick with a long boss. Machine this all over and bore to a snug fit on the motor spindle. Next drill 3no., 8 or 10mm bolts (see drawing) and then secure to motor spindle. Being machined all over, the balance should not be a problem. Next acquire three or four discs of thick plywood or M.D.F. but plywood is better – the discs of a diameter to suit your abrasive.

To the back of each disc attach with glue and screws a disc of 1/4” plywood about 8” diameter. Keep the screws well to the outside edge. Each thick disc now requires turning to size and the attached thin disc boring to a close fit on your aluminium faceplate. Upon the faceplate make a mark against one of the 8 or 10mm holes as appropriate – do not drill clearance but rather a tight fit. Upon the outer face drill for the depth of the bolt head the size across the flats of the bolts to be used. Place the bolts through the holes and give a sharp wack with a hammer. This should sink the bolt head flush or preferably a little lower. Fill any imperfections with P38 filler and you now have demountable discs for your sander. Suitable discs of 40 or 60 grit paper should be glued to the plywood disc using PVA glue. One disc can have a coarse grade emery paper for use on metal. Here a word of caution! Do not under any circumstances grind steel if you have previously ground aluminium or its alloys. The hot steel sparks can cause a disastrous reaction (thermit welding).You have been warned!

Mount the motor on a suitable base, blocked up so that the attached abrasive disc can spin freely. Arrange the electrics including a suitable switch to suit. A working table needs to be affixed to the front facing disc. This needs to have minimal clearance – 1/32” is plenty – if too big a clearance and work can disappear down the gap with disastrous results. Anyway, look at the drawings and you will get the idea.

Caution and common sense are required when you use such a machine. Dust can be a problem if you suffer from any sort of respiratory trouble and a dust mask is surely a sensible precaution.

If you have never used such a device – beware, it can remove flesh, finger nails etc. with consummate ease at a speed hard to believe. However, do not be afraid – use the machine and realise how much easier it can make life. Because of the dust nuisance (it gets everywhere), the device is better used outdoors and especially if much work is to be done.

With that, I will leave you for this time around. But advice – get your woodworking tools and skills honed up for the next onslaught!

Larger prints of the Drawing are available from the Editor on request.