Member postings for Nigel Graham 2

I think Figure-of-Eight Descenders are still used by climbers and events like charity abseils, but are obsolete in caving partly over fear of them kinking the rope (I've never seen a definitive verdict) but more importantly, they don't work with modern single-rope techniques.

I still have one or two of my acetylene cap-lamps as Duncan describes, made by Premier. I can vouch for the water charge lasting much more than 30 minutes though, with a reasonably-sized flame (up to about an inch long). And generally carried the carbide in a screw-topped plastic jar, not its original tin!

I think the longest trip I've done on them lasted about 8 hours, reaching the practical end of the stream-way in the Grotte de Gournier, in the Vercors, of SE France. We were all using Premier carbide lamps on that trip; we refilled them completely before starting back out, but topped up the water as and when necessary or precautionary. So one charge of calcium carbide for about 4 hours - generally these lamps' limit. That was a while ago... 1975 in fact.

These lamps were originally made for miners in the methane-free conditions of metal-ore and ball-clay mines, and underground stone quarries.

When Steve Baldock built his (third-scale?) Ruston steam crawler-tractor some years ago, (sold since I believe) he fitted it with proper acetylene lighting, but using as gas generator a modern caving one inside a replica of the original.

'

It's a curious experience sitting alone in total darkness, and many cavers find it rather unsettling and soon put at least a pilot lamp back on. I've found if I hold my hand up in front of my face, I can "see" a vague image of it as a sort of silhouette even darker than reality. Strange I know but I assume it's the brain expecting the hand and trying to form the image from non-existent optic-nerve signals.

Water is one thing, but sitting in the dark in somewhere like Sand Cavern in Gaping Gill is even more intense because it is a very dry chamber and there is no sound from anything around you.

I think engraving and polishing must be the oldest metal-finishing trades.

Having seen decorative metalwork as early as Bronze-Age in Dorchester Museum, I woinder if they used metal tools or flint gravers?

A couple of years or so ago the Dorset Echo published a photo of the back of a bronze mirror, decorated with dozens of overlapping scallop-shell patterns. Accepting a newspaper's normal photograph definition is not as fine as a standard photographic print, looking at the image of the mirror closely you could see the tiny irregularities in the spacing and curves of the shell ribs you'd expect from hand work with what to us would be crude tools - but none had slipped over the borders.

If anything those tiny imperfections stress this was the patient hand work of an unknown craftsman or woman millennia ago, working with this up-to-date material with so many practical and aesthetic possibilities.

I don't know where it is now, but the mirror's structure is a very elegant circular reflector on a handle composed as I recall, of a row of three toroids.

It's interesting and rather awe-inspiring to see that the decorative work of many otherwise functional items made now, still often uses motifs developed hundreds or even thousands of years ago, as the second of Gary Wooding's photographs show by all that Celtic knot-work.

What is the most glaring omission in all the public waffle about leaving the crude oil in the ground (as that young lass from Sweden thinks she's eminently qualified to tell Governments to do), or in the more serious warnings about it running out?

Anyone spot it?

If you do are far more on the ball than most politicians, reporters and "green" (!) campaigners put together....

There's a clue in RMA's comment that politicians don't think things through.

Blasted silly-face symbol! Sorry, I forgot the space before the quote mark.

Had a rest from the Worden tool-grinder parts; finished mowing the lawn ( a bit at a time over a few days while my knee is still a bit weak); started examining how to modify the fixed steady that came with the Harrison lathe, actually fit the lathe!

No maker's name on it I've no idea of its origins, but careful measuring showed it has the right centre-height and is about the right base width, if I can alter the shallow V-notch in it to fit the Vee on the lathe.

Now how to align a highly-irregular casting on the milling-machine. The only machined mounting face is that which contacts the lathe bed, so I need to align it with the V-notch and base surface so once modified the fitting will stlll be perpendicular to the lathe axis....

First job then, make some mild-steel cylindrical squares that clamp directly to the milling-machine table; one to align the V-notch, the other or an angle-plate for the flat area of the base. Then I can machine the fettled-casting surface of the normally-vertical face for bolting to an angle-box for milling the new notch.

Parted off the first of one pair of cylindrical squares, 1.35" dia as closely parallel as I could manage (about 0.001" over 1.6". It was a struggle!

I no longer have any faith in carbide parting-tool inserts - at about £5 each and not lasting 5 minutes let alone the 20 typically claimed in their manufacturers' catalogues for ploughing half an acre of anything from lead to the most exotic of un-machineable alloys. Then could just not get it right with an HSS parting-blade. Sometimes they work fine, but at other times.... There must be a secret to them I've not yet found, though their disproportionately large side overhang from the rear tool-post hardly helps.

Too much stuff, too little room.... I know the feeling!

Toady? Oh, cracked on with making the turned parts for the Worden Tool-Grinder.

"Fine knurl" it says on some, but my clamp-type knurling-tool is too small. Never mind, on these larger diameters I prefer scalloped to knurled surfaces, though more work to produce.

One part has an inch of 4otpi thread on it. Wanting this to be good fit (well, less wobbly) on the mating part I screw-cut it. Oh what a palaver!

You'd think cutting a 40tpi Model-Engineering Standard thread on a Myford 7, would be easy to set up. In standard trim, it would be! The change-wheel chart fitted inside the cover lathe assumes a 30T driver, and my lathe has a 20T.

It took me a good hour to find a wheel combination that would both give the ratio, AND fit the frame, which must be one of the flddliest bits of model-engineering equipment I've encountered. You need three hands with fingers like a Daddy-Long-Legs' limbs to manipulate that lot in full compound mode.

I must remember to write down the eventual combination for future reference...

Anyway, all done, then for rest (after a brew!) I examined the fixed steady that came with my Harrison L5 lathe, to see if I can adapt it to fit. There is no maker's name on it, and it's very scruffy, so it's not really saleable, even if I could find a proper Harrison steady to replace it.

'

Next task... have a look at the Myford web-site to see if it lists a 25+30T cluster gear. It looks as if the pinion on my example can be changed, but it's so tight I am not convinced and I am not going to risk breaking it.

Incidentally, needing to know the thread depth, I had to look beyond my various model-engineering books, which seem to omit such details. I found the answer in my copy of the Newnes Complete Engineer - Data Sheets, given to me by a capstan-lathe turner at work over 30 years ago.

These sheets, in a book-type double folder, were published for professional engineering designers, machinists and fitters in 19-summat but long enough ago, to include overhead line-shaft proportions and that most up-to-date of production machines, the Ward 2A Capstan-lathe.

A thought regarding Fireless Locomotives...

Anyone here had any experience driving one, so can confirm or correct me here?

Were they charged with steam, or with water at boiler pressure and temperature?

Surely... :

- If steam only, as it is drawn off, the reservoir's pressure and temperature would drop very rapidly.

- Water will retain its heat for a lot longer, refilling the steam space by evaporation as the locomotive moves, and with a far lower pressure and temperature fall.

A parallel is the aerosol spray can, whose propellant is a highly-volatile fluid kept in that state only by its own vapour pressure, but maintaining that pressure to the end.

Plumber's Tape. That would have been my suggestion.... once.

A boiler-testing seminar I attended in Taunton last year (? 2017?) said NO to PTFE tape, admittedly for boiler mountings and test-plugs, because small shreds can escape and cause trouble by blocking small steam and water ways. Where the fitting is up to a shoulder, as it usually is, use a thin fibre washer. I'd add, or where the design allows, an O-ring in a correctly-sized groove in the joint face.

I've certainly noticed a lot of people use umpteen turns of PTFE tape on a finely-threaded fitting as if more means better, but it never looks quite right. It does force surplus tape out of the joint.

Wondering the professional Plumber's view, I asked a friend who is a central-heating installer and accredited gas fitter. He says he uses pipe sealant, but very rarely uses PTFE tape, less than one small reel a year.

I have heard it's really a thread lubricant rather than sealant, but this probably in pipe connections that rely on BSP Taper threads, so tightly metal-to-metal. That is all right for heavy steel pipe but not robust enough for the much more delicate fittings on our miniatures.

I've investigated using a spread-sheet (MS 'Excel' to calculate change-wheel combinations.

'

It proved an interesting exercise, showing some threads apparently awkward for the equipment available can be solved with pitch-errors within tolerance or feasible by part-cutting then die-finishing, at least over short distances - more common than long threads. (E.g. studs, pipe-fittings.)

Some unlikely threads even proved numerically possible, though perhaps not to aerospace standard, on my EW 2-1/2" lathe, limited by its 8tpi lead-screw and change-wheels of 25 to 65T X 5T increments.

Using a spread-sheet, including such tools as absolute cell references, allows you readily to model the effect of changing just one variable so as to minimise the errors, and show them singly and cumulatively.

I'm a bit rusty on Excel now, but it may be possible to plot one " side " of the true and calculated threads at a readable scale, as two superimposed traces on a Cartesian graph, to show where the inaccuracy starts to exceed tolerance. NB: this is not a design-drawing, but gives simply a series of sharp triangles on the thread's axial plane.

(I once used a manually-drawn version of such a graph to establish using a metric taper-tap to "pilot-tap" a hefty BSF thread in heavy steel plate with existing but slightly undersize holes!).

Don't forget sufficient space for access at each end of the table, over the full rectangle enclosing the table's corners in full long-travel and cross-travel in both directions.

You might not need to stand between the table-end and the wall, but still need room to manipulate the hand-wheels, position bulky work-holding, reach the drive-belts (if it's not a geared-head machine - I don't know the WM16).

Milling-machines are greedy for space!

The Myford VMC has a quill - rack-and-pinion only, not fine-feed, which would necessitate using the knee. I have the impression quill-fitted mills are the majority.

'

Vic -

" albeit with fairy small travel "

You're lucky your workshop faerie-folk help you. Mine just delight in hiding things.

One area of confusion this thread shows is that of different countries with different ideas and requirements. The UK for example is still terrified of stainless-steel boilers yet other countries use them - though perhaps trade-only thanks to the considerable technical difficulties. Similarly with silicon-bronze: again perhaps trade-only to ensure the correct of many grades of a seemingly simple trace-alloy. On the other hand, the Australian code is regarded with suspicion in the UK as being excessive; outlawing even popular, tried-and-trusted conventional locomotive boilers on mere principle - but I admit not knowing how true or rumoured this is.

'

The UK model-engineering bodies follow the EU's Pressure Equipment Regulations, which unless radically revised from my own, early, copy, have very little technical information, and thinks PVs are only made from stainless-steel or aluminium-alloy. Note the irony?

The PER were obviously by lawyers not engineers, and primarily part of the political and economic scheme badged "CE" mark, and to keep "Notified Bodies" in clover. However, they are clear that safety is paramount in design and construction, and contain the clause, the pressure-vessel "does in fact have to be safe". I think its "in fact" is literal, not merely colloquial - though in entirety the clause seems an afterthought.

("Notified Body" is EU-Speak for a Laboratory, approved Governmentally for testing products.)

Where that leaves us in the UK is having to work to our own, MELG-agreed Test Code, "The [Colour] Book", presently orange. It takes in the PER's random technical specifications intended for the petro-chemicals and nuclear trades, and if anything gilds them. Unravel the book's tangled layout, work to its guidance and you won't go far wrong, whether you buy a commercially-made, CE-marked boiler or make your own.

For amateur construction, really we are limited to copper only, Steel boilers are now so problematically wrapped in materials' and welders' specifications that they are trade-only - so must pass all those costly PER hoops.

Copper: there is really only one grade of copper, the essentially-pure metal, easy to buy through the model-engineering trade; and for amateur construction at least not needing materials certificates. The processed form called "Phosphorus De-oxidised" is for welding, but really again, trade-only practice.

Use a recognised, published design if possible, or at least use those design principles, use the appropriate bronze for bushes (not brass); seek your club's boiler-inspector's advice.

Now I recognise two problems with the last point.

1) I am lucky - my two societies' boiler-inspectors understand their roles, and what the Orange Book actually says. Such volunteers - who do not need a professional engineering background - have an escape in the code, allowing them to decline testing a boiler if they have good reasons that can include it being too far outside their experience. Unfortunately there seems many anecdotes about some boiler-inspectors being far too finicky, refusing the test or failing a boiler, through fear of the responsibility and not understanding the spirit and requirements of the MELG Code. Though I have some sympathy with the latter, as the book is confusing.

2) You might not actually be in a model-engineering society! That almost certainly means if you wish to steam the plant in public, to be covered by insurance you will have to buy a commercial steam-test. Not difficult to arrange, but expensive. My advice, frankly, is to join a MELG-affiliated club if at all possible... but on a social note, please don't join merely for the boiler test. The society will test it, and for "free" (it is not allowed to charge for testing boilers), but as with any social organisation respect is a transaction, and you are expected to give as well as receive, take part in its activities generally, and so on.

'

So to answer the question, by all means study the reputable, up-to-date model-engineering literature on boiler-making, make the boiler... but don't so "by way of trade". In other words while I think it reasonable your friend buys the materials, do not charge for your time as that would make a somewhat grey area even greyer.

'

Selling an amateur-built boiler, with current test-certificate, as Roderick says, is not a problem if it's a private sale. The law is concerned that new boilers "Placed on the market" and "by way of trade" (i.e. commercially) after a certain year - I forget when it was - comply with the PER. It does not apply to older boilers though obviously these still need testing.

Nor as far as I understand it, would it apply to an ad-hoc sale of a boiler as part of a project unfinished by illness or death - it's still a private sale of someone's private possessions. Though the buyer would still reasonably want test-certificates (the MELG scheme allows for these being long-expired or lost, by treating the boiler as if "new".)

Oh, I never thought of that, John!

I beg their pardon!

The two parts came heat-sealed together, with no suggestion of machining to finish, and a 2mm diameter discrepancy is larger than I'd have expected. I know that's normal practice for a chuck back-plate but they are normally sold individually.

Mind you, my opinion was a bit couloured by the experience with that hand-wheel.

When Needs Must, Nick!

I put some levelling-screws in my Harrison lathes' cabinet base-plate, already drilled but not tapped. According to the Harrison manual, you don't bolt these lathes down but level them with the screws provide - in my edition of machine they weren't. "Level" is defined as sloping slightly to the chip-tray drain.

I can assure you completing hand-tapping five 1-1/8"BSF holes in 5/8" thick steel with a hard skin on the underside and the holes a bit under-size for the thread, entailing wielding an ordinary spanner as "tap wrench" while lying on the floor in very cramped and awkward positions, and expecting naively to tap the threads square to the surface....

..... is a labour of gritted determination over several days.

That's even with the help of a somewhere-near-diameter Metric tap to quarry away some of the steel first. ( I drew scaled-up thread profiles first to determine how many turns I could get away with before the pitch and angle errors became significant.)

What the hell is wrong with this site's logging procedure? It keep throwing me back to previous posts, other sections, ,all sorts?

I reached here only after brutally closing the browser itself (BTcom) and starting again.

'

Anyway,. today...

A little light garden trimming - I'm nor fit enough yet to risk pushing the mower around the, umm, lawn. Moved a few pebbles on the "beach" forming one end of the pond so some tadpoles behind them would not become stranded as the water slowly drops.

More work on the Worden Tool-grinder this afternoon. I'm trying to plan operations to minimise repeated machine-setting, so at the moment am concentrating on the turning to leave all the milling on the second-operation parts until I am ready to mill all the rectangle-based bits.

Remembered I had bought an ER32 collet set for the Myford, partly to use with that lathe's chucks on the rotary-table.

Now, wouldn't you think factory making a collet-chuck and its spindle-nose adaptor, and heat-sealing them in respective halves of a thick-walled polythene bag, would ensure the registers match?

No doubt when made in Beeston they would match to within very tiddly bits of thous. These didn't. Oh my word no!

Unfortunately I'd bought these quite a while ago, I can't remember if at the trade-stand or mail-order, nor from whom. Possibly not the present incarnation of Myford, though possibly from the same People's Glorious Capstan-lathe. So returning them was not possible.

Luckily the male register was the oversize one - by TWO WHOLE MILLIMETRES - and on the spindle fitting. Had it been the other way round I'd have had no choice but to ring Myford to order the appropriate replacement, and stress the diameter needed.

Fortunately too, once it was on the lathe I could detect no appreciable run-out, and though the bush had a ground finish (albeit only to look pretty), nor was it hardened. With utmost care and using the finest self-acting feed and several spring-cuts with a sharp HSS tool, on a lathe whose parallelism, rigidity and feed-smoothness depend as much on the Auguries rising in Orion as they do on my Leo's chosen constellation, I succeeded in what should never have been necessary.

I half expected the holes for the three cap-head screws holding the two parts together, to be on different PCDs, but no, they weren't.

++

This isn't the first fun I have had with modern-day Myford-labelled accessories.

I was able to replace a new lead-screw hand-wheel that just would not fit - the driving slot was visibly so far off-centre it was obvious the factory had made no attempt to machine it properly. The register on the nose-piece I have for rotary-table work is rather too tight, too, but that's better than loose. Nor does it have even a plain hole down its axis.

Thank you for al this information & experience. I'd been thinking of making a pumped-coolant system on a small trolley, moveable from machine to machine, but may be better off staying with brushes, simple drip-cans or spray bottles (ex-kitchen cleanser).

The stuff to use though would be one of the modern soluble oils, either indigestible to bacteria, or containing biocides.

Afraid I can't help with drawings, but on the first point I think you are worrying unnecessarily. The oil will soon purge the pipe by merely pushing the air into the steam-chest.

Assuming normal practice, in which the oil-pipe is connected to the steam-circuit simply by a union nipple:

I think you will find a test-point as you suggest will not really test anything because the pipe is open-ended either effectively to atmosphere when the engine is cold, or to steam in running conditions.

In normal service the lubricator soon reveals something is amiss by the oil-level not dropping; and I have never seen nor heard of anyone fitting a bleed-valve in the oil-line, in miniature or full-size.

'

Under running conditions a bleed-valve between pump and valve-chest will simply emit a lot of steam. A pressure-gauge there would show a pressure - but of what? Oil or steam? Or some resultant pressure? It will not show oil is actually being delivered to the steam circuit, though a blockage downstream might create an oil pressure above boiler pressure.

Used cold, and turning the lubricator manually, the bleed-valve will emit some oil, but most of the oil will take the easier exit, into the steam-chest. A gauge will show if the pump can give adequate pressure only if the pipe's outlet is plugged, or the gauge is connected to the pump directly - i.e. no outlet for the oil.

'

So where does this leave us wanting to test the mechanical lubricator?

In service: A mechanical-lubricator is self-purging, and shows it is working by the oil-level falling. And by very oily soot in the chimney top if set to be a bit too generous - at least erring on the safe side.

Cold: The lubricator can be tested new, after a service or if suspect, for flow by an open outlet, and for pressure, by direct connection to a pressure gauge; and manual rotation.

The oil-line including any in-line check-valve can be tested (I have known them become blocked) only with the engine cold; by disconnecting the delivery end and again, operating the pump manually.

I receive unsolicited messages including sample / tutorial projects from Alibre, which are pointless because the Atom 3 trial licence has expired. Surely they know I have not bought the full version?

SolidWorks' own web-site does not give prices, leading me to think it's not interested in private buyers. However, the software itself is reputable even if the company's sales people aren't, and it was my employer's choice for its engineering designers. It also produced a student version for schools and colleges, with the cynical purpose of producing for employers, recruits already having been introduced to CAD - but only Dassault's products!

It was observing that use (not using it) which influenced my decision to take up CAD, though with TurboCAD, which was readily available at the time through the model-engineering trade, and at a fraction of the cost of SolidWorks or AutoCAD.

Boiler Bri -

Could you not simply block that supplier in the Peak District?

I made a slightly similar arrangement for my EW lathe, which has just a simple tool clamp. The bits are typically ground from 1/4" broken drill-bits, FC3 cutters etc.

The holders are just short pieces of 3/4" X 1/2" b.m.s. bar with drilled (not reamed) holes at each end at angles to give some height adjustment. The bits are simply gripped by grub-screws.

Not quite Dickson finesse but better than fiddly shims under individual tools: if not quick-change then the semi-fast service!

I have an old (Warco?) 4-point face-mill having carbide tips brazed to the body. I've wondered how feasible it would be to remove the worn-out tips (somehow) and convert it to renewable insert form, either carbide or with HSS bits rather as Malc has made. Only it's MT3 and my mill now has an R8 spindle...

Mainly model-engineering and related (I'm presently making a Worden tool-grinder - a Hemingway kit).

Of the ones-off and "specials" - years ago:

- New king-pin bushes for Bedford CA vans I owned then,

- A set of small brass bushes for one of the CAs, to take out the wear in the rod-and-clip throttle linkage that was so bad it lost a third of the motion between accelerator pedal and carburettor..

- An adaptor in snazzy black plastic plate to hold a new shower mixer-valve on the previous unit's existing holes in the tiled stud-wall,

- A stand off, in Nylon, to take the shower head further out from the wall, necessitated by the bath end being a few inches from the wall,

- Perhaps the most awkward, a special connector for a pub trade CO2 bottle, being principally a short brass rod drilled though, with a very non-standard metric thread on the outside and a pin silver-soldered through as a handle. That on a 2.5" BGSC EW Stringer lathe with determinedly inch lead-screw and 25 to 65 T X 5T change-wheels - and of course no die or chaser to finish the thread to profile. It was for a heat-exchanger central to a warm-air breathing kit used by a cave rescue organisation to ward off hypothermia in the rescuee. The heat source is the exothermic reaction between the CO2 and soda-lime.

- Assorted parts for the spoilt-raising, manual winch for a cave "digging" project on Mendip, in which I am involved when not having knees replaced. It's essentially a simple rope-reel running on plastic bearing bushes on a fixed scaffold-pole axle, and I made the two side-frames from scrap miniature-railway bar rail. ("Digging": the signs are there that a cave is down there somewhere, but its entrance is obstructed by a very deep mass of boulders we are carefully and patiently negotiating and stabilising our way through. Some 150 feet deep and still going down...)

- Oh and when I've a few minutes to spare, my steam-wagon far too long in the making!