Brian and Alice Favell relaxing...

My late father, who died in 2006, retired as a Vicar from a parish in South Wales. However, his earlier career was as a draughtsman for B.T.H. Rugby, and then as an Electrical Designer for A.Reyrolle, Hebburn on Tyne, where he designed and patented many relays, switches and other things I don't understand....
In the midst of this, he spent 25 years building a 2 1/2" gauge 'Austere Ada' - the 2-8-0 by L.B.S.C. - which, on completion in the mid 60's had to be sold to pay for a fire to heat the house!

Since his retirement, I took it as my bounden duty to stop him from getting bored by landing him with all sorts of work - first of all, the completion of the design of the loco that became 'Alice', then with the machining of substantial parts of said loco! Seriously though, ten years ago I didn't have the slightest ability to build a live steam engine, but by sheer determination, with the aid and advice given by Dad, 'Alice' was achieved - teaching us both loads.....

Meanwhilst, Dad has written various useful things at my request, and these are some of them.

Fladbury, the home of Brian and Alice Favell in flood

Lathe Chat
My first contact with a lathe was when I was about 12. My father bought - with much scraping of pennies - an Adept 1.5/8" lathe. It cost a pound (another five shillings would have bought one with a screw feed on the tailstock, but Dad couldn't afford it. In 1935 money was tight).

Dad mounted it on an old treadle sewing machine stand, and I learned the rudiments of turning between centres while standing on one leg. He was greatly disappointed with it: no chucks were available in that size, and since he wanted to build an 0 gauge Royal Scot, turning wheels was an impossibility for him, so I played with it but never did any serious work.

That came when I was 17 when the local club (1940, this was) had a 4" round bed Drummond which it was looking after for someone out on active service. I learnt a lot, first one-legged but later, when we managed to put a motor on to it, in more conventional pose. I quickly proved LBSC's adage that the first essential in turning is a sharp tool with the right angles on its cutting edges. The second was to take great pains with its mounting - tool, toolholder and all - otherwise one had great trouble with chattering. (Fairly soon after that a Christmas Model Engineer had a fascinating - cod - article about machining twelve-sided cylinder bores to accept pistons made from the then brand-new thruppenny bits. The author's (alleged) method was to adjust the chattering until he got twelve chats per revolution!)

As an apprentice at BTH Rugby works I spent three months of 1943 in the turbine machine shop on an old Dean, Smith and Grace lathe with a 3 foot diameter faceplate, turning 18" diameter rings to a high quality finish for naval mines. The drive was via a 3" wide leather belt from overhead shafting. To change speeds one had to flick the belt with a stick (and of course the lathe running) from one pulley to another.

I learnt a lot about tools and their mountings from this, and ended up machining these rings in 20 minutes floor-to-floor (my first one took two hours) which was the same time as given to the vertical boring mills next door for doing the same job - but they had a range of tools in turrets, while I only had one tool in a single toolholder.

So they took me off this machine and gave me a 6" Smart & Brown - it had just had its main bearing renewed, and was a delight to use - with which I turned all sorts of things to a standard tolerance of +/- two thou. Also I did the fitting bolts (two per turbine casing) which kept the halves of turbine housings in alignment. I would be given two rough machined bolts about 7/8" diameter, with a dirty little scrap of paper on which the fitter had inscribed in pencil something like "Plus two tenths", which meant he wanted the essential diameter turned to the nominal size plus two tenths of a thou exactly. A tenth either way and I had them thrown back at me! (in that works +/- two thou was the standard - finest - tolerance for centre lathes; +/- two tenths was the standard for cylindical grinders). Without boasting, I should say that I didn't scrap many!

So these are my credentials for writing about turning today. A range of small lathes of my own, from a prewar Myford ML3 (I think it was) through a new Perfecto in 1967, an old South Bend in the 1970's and 80's to my present Warco 500 only two years old, have all taught me new things and reinforced my experience of old things. Of course the Warco was invested in for the specific purpose of turning big wheels for Giles' 10.1/4" ambitions.

And of course I have had problems: one always does, however new and however expensive a lathe is. If I write about my Warco's problems it is not to criticise this machine. I am delighted with it, with its size, guts and performance. But like any other machines it needs to be learnt; its good and bad points, its abilities and objections.

The first and obvious objection is that its minimum speed is 160 RPM. No problem if you are turning drivers for a 3.1/2" gauge loco, but a bit daunting with 12" diameter wheels. So let it be said that it copes very well when one uses the right methods. I found that the Colchester Student lathes at our local College had severe limitations for this work. They had the slow speeds and the large motor, but they would still chatter and object to being pushed to heavy cuts.

Bearing in mind that my Warco has a 3/4HP motor, it can only shift so many ounces (or pounds) of metal in an hour. It runs at three times the speed of a Colchester and takes a cut of 1mm (40 thou) or less, while the Colchester objects severely to 3mm (1/8") cuts at the slow speed. So if with the Warco I can find tools to stand the cutting speed , and if at 1mm cuts the motor is running at full power anyway, what's the odds?

So I go back to my first lathe and LBSC's strictures about sharp tools etc. In a year of use I have found out one or two things. My time in industry taught me very early how important the mounting of tools is. I very soon saw that in industry, parting tools particularly are almost universally used upside down at the back of the work. This is not just a gimmick: it is a recognition of the way tools and their mountings spring (give) under load.

Tools conventionally mounted at the front, flex downwards and inward (towards the work) under load. With a back toolpost they flex upwards and outwards. The first causes dig-ins, broken tips and so on: the second gives to the point of equilibrium, where if a tool is heavily loaded it eases away from the work and reduces the load. Hence in the first case, chattering: in the second case clean cutting and few problems!

So with my wheels (Giles' wheels for No 2!) on the Warco I tried out this technique. No need to use a back tool post: simply mount the tool upside down in the regular tool post and run the lathe in reverse! In this condition I get 1mm cuts, no chattering and clean cutting. The conventional way I can only use 1/2mm cuts and get continual trouble with chattering and dig-ins. One dig in means one tool tip chipped - which comes expensive!

This method doesn't work on every lathe because the chuck unscrews: disaster! But the Warco 500 ( and I think this applies from the 300 upwards) has a flanged mandrel nose: the chuck is fitted on a spigot and fixed by three M8 bolts screwed in from the back. The Colchester Student has a large taper recess with a keyway, its chucks are mounted on a matching backplate (with a key) retained by an enormous ring nut. With both - no problem.

TOOLS
At 160 RPM, on a 12" diameter wheel, the cutting speed is 500 feet per minute - nothing excessive with modern tooling, either tungsten carbide or throw-away tips. With both, a dig-in is fatal. But dig-ins can be avoided by working upside-down: the only outstanding problem with my wheels is that they are flamecut from 40mm steel plate, and flamecutting produces a rough and hardened surface. Either quality can ruin a tool even without a dig-in. But a consultation with Greenwood Tools at Castle Donington two months ago ended in the specification of a grade of tool hard enough and tough enough to cope. I have a toolholder which uses triangular tips held by a camlock arrangement in the centre (I think it came from Chesters). The tip of the toolholder is angled to give the necessary front clearance, so the tips are double-edged - top and bottom - and have six cutting edges. I cleaned up the rim of one wheel using only one edge, which still has life left in it. Eureka!

Using the tool upside down with the lathe running backwards has another benefit. Instead of spraying up and outwards all over the place, the swarf curls tidily downwards and drops into a handily placed carrier bag suspended between the leadscrew reversing lever and the saddle handwheel! One good session on these wheels can produce as much as two Tesco carrier bags of swarf: it's just as well we have a domestic recycling centre close by -Throckmorton airfield where they were going to put the asylum seekers.

Next point: in my apprentice days I very soon saw that every machine tool with pretensions to mass production had suds laid on. I don't know whether this name was universal: I have heard it called 'white water'. It is actually (was 60 years ago) soluble oil dissolved in ten times or more of its volumn of water. If - like me - you worked on a machine which didn't have piped suds, you had an old half-gallon paint tin filled with suds, and a brush, applying it every minute or so (one-handed while you kept the cut going with the other).

I organised piped suds on my last lathe (an old Emcomat 7). This machine had a geared head and speeds up to 2000RPM, and the snag was that however you tried to control the flow, it was sprayed by centrifugal force all over the place - and over me! So although I might some time install piped suds on the Warco, I am quite happy with this job using an old spaghetti tin filled with cutting oil, plus a 1/2" brush. In those quantities there's not enough to spray around, just a thin film that clings where you want it and makes beautiful smoke. It also keeps a thin coating all over the slideways and other parts, keeping rust at bay. Of course that machine has self-act on the cross-slide as well as the saddle, so one just leans nonchalantly on the tailstock applying oil at intervals . . .

Yes . . . .while I am about it, PROBLEMS THAT I HAVE HAD . . . . .

Self-act: the more expensive lathes incorporate some sort of friction device to prevent the machine injuring itself. Colchesters, for instance, have a little click lever that you pull upwards to engage self-act, and if the going gets too hard it clicks out again. The Warco doesn't have that feature: the self-act is a gear drive right through, and if you let it drive up against something solid a little gear in the saddle goes BANG! I am racking my brains to think of a way to incorporate a friction element into the saddle gearing, in the meantime I am trying to be very, very careful.

But there is a little trap on the machine that I had to find out the hard way. On my machine there are three holding down bolts. Two are at the back, and out of harm's way. But the third is under the leadscrew between the gearbox and the saddle, and a standard hex head bolt fouls the corner of the saddle as you traverse to the left. You can see there is at least two inches of travel left before you hit the gearbox, but you don't see the bolt head until it's too late!

I think if you are using one of the chucks there is no need to traverse the saddle up to that point . . but of course I mount these big wheels directly on to the mandrel nose, and . . . . bingo.

Of course NOW I have put a special bolt in with a very shallow head to clear the saddle, and I have thought of mounting a limit switch to shut off the motor if the saddle tries to go where it shouldn't, but there's still the cross-slide self-act. It's all right coming out (the cross-slide just winds itself off the nut) but going in you could stll go far enough to lock up solid and . . . bingo again! So any other ideas would be very welcome!

I have replaced the square indexing tool box supplied with a hefty quick-change setup picked up second hand from (again) Castle Donington, and it seems to have been a good move. Nevertheless running upside-down and backwards will help to prevent dig-ins etc. with the original toolbox.

I haven't yet used the milling head for milling, but it is a magnificent heavy-duty drilling machine, and I have ditched my B & Q pillar drill in its favour (there wasn't room in the shed for everything anyway). Talking of room, my shed is home-built to fit the site, and is roughly triangular with three eight-foot sides: the fourth side is fifteen inches. In that space (don't ask me how) I have fitted this big Warco WMT500, a bench four feet long with a vice for the hand work, and a second-hand bench mounted Boxford 8" shaper which is a gem and a delight. Just for good measure, the shed is three feet and four steps above the back yard, and with help from three other blokes, plus a garage engine crane and a half-ton hoist in the tree, we got the Warco (weighing over 4cwt) into it without harm to it or us. I think when it was finally positioned and bolted in, we looked at it and still didn't believe it! There is room inside to stand, though not to walk around. Finally, visualise the task of picking up from the floor wheel blanks weighing about 60 pounds each, putting them on the cross-slide to drill and tap them, then finally mounting them on the mandrel nose where they have less than 1/8" clearance to the bed. It's a mad world! Oh, yes, and I am now 79 . . . .

Running Three Phase motors on Single Phase
I could write you pages on pages about the technicalities of 3-phase supplies, about phase angle and phase shift, lagging and leading power factors, inductance and capacitance and so on. But if you know it you don't need me to tell you, and if you don't know it your head will start spinning like Colonel Dedshott's when he listens to Professor Branestorm. So let's skip that.

So to the first problem - voltage. Industrial motors run on 415 volts 3-phase. They have three identical windings in the stator (their rotors are not wound at all - they have what are called squirrel-cage windings which are generally of aluminium, cast in situ). For reasons best known to themselves, manufacturers of 415 volt 3-phase motors generally connect the three windings in star formation (see Fig. 1). Most often, if you look in the terminal box you will see six terminals in pairs (probably marked A1 and A2, B1 and B2, C1 and C2 or something similar). You will find A2, B2 and C2 linked together to form the star point. To make your motor capable of running on 240 volts you need to change the connections to delta formation (Fig 2). Remove the A2 B2 C2 link and instead connect A2 to B1, B2 to C1 and C2 to A1. Each winding will then have 240 volts on it, and everything will be hunky-dory.

To the second problem - how to make it run on single-phase supplies. We need capacitors. And although the connections are straightforward enough I am afraid we have to resort to trial and error to make it work well, because the amount of capacity needed varies according to the rating of the motor and the load on it. More particularly, a capacitor which is fine when the motor is running on full load will likely not be enough to start it.

Capacitors are easily available these days, but they must (a) be designed for use on AC and (b) be of an adequate voltage rating and value. Ideally you want capacitors designed for power factor correction (don't bother too much about what that means!). The most likely products are those which are used in fluorescent lighting units. If you can buy spare ones from an electrical factor or from Maplins or Radiospares so much the better; otherwise you may have to resort to breaking up an old lighting unit.

When I first made such a conversion it was with a 1/3 hp motor. As far as I can remember it needed about 16mfd (microfarad) to run under full load, and about twice this for starting.

So to the nitty-gritty. Having modified the motor to delta connection, connect it (via starting switch, contactor or whatever), terminal A1 to line, B1 to neutral. The capacitor can go between C1 and neutral (for preference do this near your starting switch). Take the belt off and start up. It will probably start cleanly and then roar at you when up to speed. Put the belt back on and try again, if necessary kicking it over by hand. If it then runs quietly under load, fine. If it grunts and groans when up to speed you've probably got too much capacity.

When you've got it running right under load you probably will complain that it doesn't start or takes too long getting up to speed. To get over that you need to switch in an extra capacitor at the instant of starting, and switch it out again as soon as you are up to speed. Yes, you can do this with an extra switch beside your control switch, but you can do better than that. The ideal situation is if you have a contactor starter, which most industrial machines have when you buy them. Note: if you have one of these its operating coil will be rated at 415 volts, which may not have enough beef to work properly on 240 volts. Then you will have to change it for a 240 volt one - your local electrical factor may be able to help.

So if you have the right starter you're quids in. The 'Start' push button will likely have two sets of contacts, only one of which is used to 'latch in' the coil. If so, use the spare set to connect an extra capacitor in parallel with the main one. Then when you press 'Start' this extra one will be connected, and half a second later will be disconnected again - which is exactly what you want.

If your starter does not have this spare contact, all is not yet lost. It will almost certainly have terminals to connect external push buttons, and if it is a new starter there will be a diagram inside to show how to connect them. Buy from your factor both a 'Start' and 'Stop' button, the latter with a large mushroom head for easy use in emergencies (both will have two sets of contacts). Mount these in a convenient place, connect according to the diagram and wire the capacitor in to the spare contact as above.

If your machine does not have a contactor starter your only reasonable resort is an extra switch to connect the starting capacitor in parallel with the other one. Ideally use a spring-loaded switch or pushbutton so that it opens the circuit when released.

One last point: according to Murphy's Law, after doing all this you motor will be running the wrong way. No bother: simply interchange any two of the wires connecting starter to motor to reverse rotation.

Y'Da