Member postings for Nigel Graham 2

Why has your post appeared twice? This seems to happen fairly often (with different people!).

Likewise though - I am used to both metric and imperial but by work rather than the inch-based model-engineering.

Many of the trade drawings I encountered carried tolerances of +/- 1/64 for fractions of inches, but 0.01 or 0,005 inch for decimal, u.o.s; depending on the dimension's function. I forget the mm tolerances but 1/64" = 0.4mm.

I used metric measurements and fastenings for the travelling hoist I built for my 16-foot X 6 ft workshop - after all the materials all came in mm sizes and this is a new item not a scale model, part of the workshop equipment.

On the other hand my model steam-wagon is in inches as the original was English-built more than 110 years ago - though contains an unfortunate mixture of BS and BA with Metric fasteners. This is poor practice, I know, although sometimes for reasons like simulating rivets or to be stainless-steel.

Similarly I try to make any machine-tool accessories compatible with their host machine, be they of metric or Imperial dimensions, including threads.

The original question though was about drawings for fittings for Myford ML7 lathes, and many tools and accessories for, or designed to be made on, these lathes, have already been published in ME and model-engineering reference-books over many years. So new ones are unlikely to be at all "new" even if you suggest alternative materials or dimension them in millimetres.

The original machines were all built to inch sizes so while some constructors may well prefer to make fixtures and fittings in mm, at least some important dimensions need match inch-based ones on the lathe: spindle and tailstock diameters, the T-slots, bed, etc. So somewhere along the line someone needs convert them, be that the designer or the maker; and the conversions either way will not be nice neat integers.

In making the drawings, it matters not a jot whether CAD or manually drawn as long as they look proper but more importantly, are clear and free from frustrating mistakes!

It may be possible to transmit a CAD file to the buyer electronically - but he needs the same or compatible CAD software and a printer for the drawing's A-number sheet size. Squeezing drawings created for an A2 or A3 sheet onto A4 for example, risks dimensions and other annotations, and fine details, too small to read. I'd rather buy paper drawings in their proper sheet sizes, from the start.

Mike -

I think your last sentence summarises it admirably!

Harry -

We all do our best to produce decent-quality work as accurately as we can but model-engineering has never worried about stating tolerances and formal standards on drawings because we make things to suit our workshops and our own skills, for ourselves, not for interchangeable production; so tend to be fitter-turners rather than production-machinists.

Obviously we should and usually do endeavour to make, for example bearing-race fits as specified for the bearing types, O-ring and circlip grooves to the manufacturers' recommendations, etc., and these are not difficult to find (often from the part makers); but not all of us have full, ISO9001-registered metrology facilities.

By all means put those dimensions on the drawings, as they should be; but a model-engineering workshop drawing does not need meet full, formal ISO industrial standards. It's more important that the drawing is clear and unambiguous, the details and dimensions are correct and the parts made to them do actually fit each other. (If it's any comfort, even professional trade draughtspeople occasionally make mistakes - or design details that work as CAD images but can't be made!)

Holes for screws are not too problematical because many screw-thread charts show tapping and clearance diameters in mm anyway for metric, BS and American screws; suiting the commonly-available drill sets made to 0.1mm (~0.004" ) increments.

Whether I use inches or mm, I try to use nice round numbers, even for inch-fractions; especially for something entirely new.

The one to watch is a counterbore intended for a socket-spanner rather than a socket-head screw, and clearance for the appropriate spanners generally. 

The biggest bug-bear in model-engineering has anyway been the way drawings' dimensions have long been laid out, not their units. Though sticking to vulgar fractions even for parts intended to be made on decimally-calibrated machine-tools (mm or inch) parts is a secondary nuisance.

Edited By Nigel Graham 2 on 16/09/2023 08:00:05

Duncan -

True, and I think BA was based on the Swiss, Thury thread, though codified in British Standards in inches. The larger fastenings on Myford lathes are BSF or BSW though, so true rather than derived. inch fractions.

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Ady-

Nothing to do with "purist traditonal", while if your are a "practical get it done type" you will be able to use both systems. (I use Imperial or metric according to what I am making for what purpose.)

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Jason -

".... suit the oldies..."

You youngsters.....

Suit those who will be making the parts on the same lathe with inch-pitch lead and feed screws and decimal-inch dials, more like.....

Nothing to stop you measuring the original made in inches, directly in mm and making the accessories to fit but themselves measured in mm, if you are using another machine that is metric or has a dual-range DRO, but you'd be working to irregular numbers.

It would be much clearer and more logical to make all the dimensions Imperial but with decimal rather than vulgar fractions, and the fastenings all BS or BA, since if you make accessories for a machine built to British dimensions it is easier and much better practice to make them conform to the machine itself.

If you are making accessories for a Myford ML7, it is very likely you will be turning the parts on the said lathe, which was normally fitted with inch-fraction lead-screws and calibrated in thous.

Keeping the fastenings consistent also avoids the bad situation of needing three ranges of spanners for operating and servicing it! (Some of the commercially-sold Myford stuff now seems to have various inconvenient hexagon sizes.)

If constructors wish to use a rare ML7 fitted with metric screws and dials then obviously they'd need convert the drawings to mm; but printing the drawings in mm means most users will have to convert all the turned sizes to decimals of inches anyway.

A pleasure! Do tell us how you get on.

The locking-screw will be of BSF or BSW thread to be compatible with the rest of the lathe. That holding the left hand plate will almost certainly be one of those anyway (unless someone has modified it with a different thread).

I think you'd need put the saddle onto the ways without the apron so you can measure the plates' overlap to reach under the shear without touching the root; but the rest should be straightforward. They look on my lathe to be about 1/2 or 5/8 inch thick, but I've not measured that. The marks on the casting will give you their lengths. The left-hand one ends flush with the outer face of the saddle.

The locating pins would not need be anything too sophisticated because they are not heavily loaded. I'd use a short piece of silver-steel or stainless steel for the locking-plate guide-pin - not hardened - but the ones in the fixed plate could be mild-steel or perhaps roll-pins.

That'd be an easy one for me to head off. I have no television and have just reminded the TVLA of the fact!

Rather like a string of posts allegedly security warnings from the Bank of Santander, all oddly titled just with a "." (full-stop) - a bank with which I have never had any dealings. Not had one lately so perhaps the liars have twigged I keep blocking and reporting them.

These holes are for two separate pieces, not one.

Your L5 might differs in some details from mine, but I have tried to investigate this from your photograph, the Operating & Servicing Manual and my own L5 - using a torch to see what's hiding under the saddle.. The diagram is not too informative and does not show the Locking and other screws and pins.

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Those holes hold two blocks called the Front Strips, Left-hand and Right Hand; the latter having a rebate in its upper surface, both having a row of three holes according to the diagram.

These act on the underside of the overhanging shear to prevent the front of the saddle from lifting, and the locking screw must be tapped into the Front Plate, RH.

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The smaller holes - the outer ones for the FP, LH (top on your photo) and the single one you marked with a red square, are for dowels / guide-pins set into the Plates.The RH plate is the locking one, the LH plate is held with a hexagon-headed set-screw from underneath into that tapped hole.

If you look carefully at your photo, you can just see where the plates were by very slight colour changes.

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I am not sure what the rebate in the Right-Hand Front Plate does, only that it faces upwards, to the right and the front - which would reduce the locking area.

I could not see this rebate on my lathe - though I might have replaced it wrongly having had to dismantle the machine to move home! I have noticed if I am a bit too heavy-handed engaging the feed with the tool already on the work, I cause a slight dig-in by lifting the saddle, but once hands-off the lathe runs as it should - so now use the control delicately, pinching the lever and trigger between finger-and-thumb and easing it upwards.

Chris -

By "Copper Tube Sleeve" for a screw-on fitting, do you mean what is actually called and should be sold as, an "olive" for a "compression fitting"? Or a liner that limits polythene pipe compression so the olive or O-ring can grip?

As Neil says, plastic domestic plumbing pipe can be joined by compression-fittings that use a thin-walled, flanged, metal bush inserted into the pipe end to give that necessary support, and a similar one may well work with garden hose and its accessories.

Even a little bit of brass or copper tube of the right diameter should suffice if no commercial version fits.

I notice one or two contributions seem to hint at the belief in the shaper (or planer) being a "roughing" tool preparatory to "finish" milling.

That should not be so. Yes, the milling-machine will perform operations the shaper can't, or simply flatten a surface more rapidly; but assuming the shaper is in good condition and properly adjusted, there is no reason the surface it leaves cannot be the finished one even if later holding milled pockets and holes.

For some fine-scale operations it may even be more prototypical, by matching the original shaped or planed finish.

My own shaper is a Drummond powered by tea and cakes, but still capable of repaying due operating care with a good finish; flat and pleasing to the eye.

Much of the secret lies, as with turning, in a properly-ground and set too. Further, on the shaper or planer its cutting edge should be below, or as closely so as possible, the clapper fulcrum (but not behind it). I recall a demonstration workshop at one ME show, having a shaper whose tool had been set by a spacer right at the outer end of the holder slot.Oops!

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I do agree though there can be very good metal under all that rust on "lumps" that look as if they had been dragged through a hedge backwards then left there. (As some of my source material indeed had been!)

Not necessarily so.

1) Some calls are silent anyway, and if left will close after perhaps 30 seconds.

2) Others will start speaking almost immediately, but are recordings; often of a woman speaking (reading) impeccable English. Try to speak back over it. A live caller will hesitate or otherwise react to the interruption, a recording carries imperturbably on.

3) Live callers, either criminals or cold-salespeople, giving a friendly personal greeting though depending on their location and own language might mispronounce your name. E.g., mine usually as "Gra-ham" with both 'a' hard. Sometimes these callers pause before speaking for some reason, but background sounds may show it is live.

Typical among these are the claims to be from 'The Windows Corporation' or even 'Microsoft', telling you your computer has been hacked or has reported a fault. My usual reply: "I know you are not and it has not" The caller bangs his phone down very promptly when he realises you know he is a liar. The bank-fraud calls are similar.

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Unexpected 'phone calls are easy to ignore if your 'phone displays the calling number or name, but many (like mine) do not. Also, the number may look like a British one (starting 01xxx) but be from abroad by a sort of parasitism or relay method that the telephone companies claim impossible to stop. Meaning they can't be bothered to try.

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Another live call that seems a recent development is from firms trying to sell you home insulation based on some "survey" supposedly already existing, or by opportunity as "our surveyors are in your area" - a variant on the old "the offer ends today" ruse. These callers tend to become very defensive, possibly aggressive, when you try to ask the survey company identity, and if you persist they hang up abruptly.

Dave -

Some way back... I think the phone contract offer was a genuine sales attempt, not a con, but hardly credible when it would have cost twice my normal payments!

Interesting though, that the chit-chat with 'Angel' might have been part of the process all along. I'd not thought of that - but they'd still not have sold me anything, and perhaps three tries without success was their limit.

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Most recent e-mail was a variant on the "need help to transfer a million dollars" nonsense. This time the liars claimed inviting me to join them in being middle-men exploiting the rarity and cost to the farmer of some vaccine or other for cattle. Reported it to both phishing.gov.uk and phishing [at] BT.

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Most recent letter was a genuine legal "scam" . NatWest inviting my home insurance renewal: all of £100 more than the same last year with no changes to the property and contract. About 33% increase for no adjustments, no claims and them doing nothing costing £100 to do. ]

I will be querying that, and am tempted to point out that we all know that insurance premiums simply establish a fund from which a paid claim is really a loan repaid by increased premiums to the insurer's profit....

Ah, but the Engineering solution is to choose a tin holding something you like, eat the contents, rinse the empty container then fill it with suitable ballast to make 400.0g .......

I recall visiting the East Somerset Railway some twenty or more years ago, with a family I know.

"Black Prince" (8F??) was standing cold, and with no apparent prohibition to visitors climbing on board - which we did. If anyone saw us they did not challenge us.

"How do you drive it, then?" my friend asked.

"Well, first by changing places. You're on the fireman's seat" , I replied.

Obviously we did not disturb any of the controls, but I pondered the "ergonomics" , a word probably unknown in Riddles' day and earlier.

From the driver's perch, two things were immediately obvious to me. The restricted view ahead, but the driving controls being all within my reach, with the ejector and brake-application handles about level with my ear. Even when standing though, I realised I could not have operated the manifold valves mainly the province of the fireman. Too high up for we of economy size, at least without being griddled by the back-head and closed fire-doors.

I did wonder how short men ever managed as Cleaners (a head for heights useful), never mind as Firemen, especially in decades past when people generally were shorter.

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{For a few years I sometimes drove a Ruston-built, narrow-gauge, 4-wheeled diesel locomotive, but had to stand for much of the trip. If I sat on the side-facing tractor-seat bolted to the gearbox top, my eye-line was only just above the edge of the windscreen, and my own track horizon created by the bodywork was a good fifty yards ahead of the locomotive! }

Just to clarify the term:

Its is an "Exploded View" [or "~ Diagram"], sometimes "Assembly Drawing" (not to be confused with "General Assembly"; and always has been, irrespective of draughting method.

It's not specific to any one make of CAD, nor indeed to CAD generally, though individual makes might have their own versions for the tool name.

Cast Steel?

(The wrapped ones might be from steel billets.)

Cavity Emptor indeed...

Since Como has been given Honourable Mentions...

Model Engineer & Electrician, as it was then, published articles on Dr. Bradbury Winter's Como in or around 1917 - I happen to have a couple of bound volumes from then.

A description with photographs of the tender, is followed by an article about some of the jigs and fixtures Dr. Winter made for building this LB&SCR locomotive.

This included an ingenious, adjustable, angularly-oscillating drive for his Pittler lathe spindle. It used a length of bicycle chain between a crank slotted for stroke adjustment on the countershaft, and a weighted treadle-like board, driving a sprocket on the spindle; augmented by angle-stops. It was for machining arcs, for example, expansion-links; the main drive I think being by treadle.

The coarse groove on the end face is by too fast feed.

I've never had much luck with the rule technique as it seems to demand looking at the lathe from just the right angle. I point the tool at a centre, and use the facing behaviour to verify the (HSS or carbide) is on centre-height.

The work's projection is too much, especially on such a slender diameter. Best to support the outer end on a half-centre, though on some lathes (such as my Myford) that can lead to the tailstock and top-slide in each other's way without turning the latter partially round.

Try using a fine power feed, too, if that's not what you're doing anyway.

It's 3 inches on my Worden, but NB this is a Hemingway Kits machine so may differ in details from the original.

(The plinth is supplied ready-folded in the kit.)

Made a 3/4BSP to 1/2" Brass adaptor for a hydraulic pressure-test gauge for my steam-wagon boiler.

I found ToolStation obligingly sells water-mains test gauges, 0 - 11Bar, for a snip under £20. These come with a short armoured flexible tube, and a 3/4BSP union nut.

I could have machined the whole thing, which will screw into one of the safety-valve holes, from the solid and I did screw-cut the smaller thread. I wanted the big thread spot-on to size and profile though, better than I could have made it, because the gauge's union nut is a thin plastic moulding!

So it's in two parts soft-soldered together; the larger being an outlet cut from a scrap plumbing fitting for me by a friend in the trade. A bit like a slice of brass studding with a hole already through it.

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And afore anyone says anything, I do know I can't certify my own engines! It makes sense though to perform a preliminary test to the MELG specifications to ensure the Club Boiler Admirers won't find anything wrong.

I've still to make an adaptor for the Club's test-set.

Though by the time the whole vehicle is ready for them we'll probably be three editions on - puce-on-yellow, even more confusingly arranged and the certificate of MENSA-level complexity.