Member postings for Tim Stevens

To answer the question 'How do I hold a tap if it's too big for my tap-holder? -

Although the tap drive-end is square, you will find that a double-hexagon spanner should fit it - but you might not find one exactly the right size. Try Metric, Unified, and Whitworth sizes. If you use a socket spanner, your tool kit should include various handles to turn the spanner - a ratchet can be useful, and for starting the thread, a tommy-bar version is best, as you can press equally on both sides.

No-one has realised, yet, how useful it would be to have taps with hexagon ends.

Cheers, Tim

Edited By Tim Stevens on 01/05/2023 17:23:00

I find it difficult to align the two words Black, and Polish, in relation to heat treating steel. It would help, too, to know what heat treatment has already been applied to the steel. If they need to be tough, it is likely that heating above the temperature at which the temper was drawn will reduce this toughness. And although modest heat does colour steel, the temperature required for a good black is well above normal tempering temperatures. But then we come to the polishing bit. This normally requires abrasion, with stages in which the fine-ness of the grit is reduced almost to nothing. The result, on steel, is a bright clean shiny surface like a mirror, a bit grey rather than silvery, but certainly not black. So, polish and then blacken. But the temperature for black will destroy the very shininess you have achieved. Once the tempering gets hotter than a dark purple, the corrosion (for that is what the colour is) becomes too deep to avoid destroying the flatness on which the polish depends.

Or have I got it completely wrong?

Cheers, Tim

Getting a single cylinder engine to run without (much) vibration is not easy - and as you approach perfection, extra parts need to be added. Balancing bits that just go round is easiest - flywheels etc just need to have their centres of gravity in the middle of the axle. Anything that goes back-&-forth requires something else which goes forth-&-back in the same time, and on the same axis. It can be done, but books have been written about it. Incomplete books ...

Cheers, Tim

A further factor, when fitting such clips. look closely at the edges of a new circlip, which fit into the groove, and (almost always) there will be a sharp edge and a slightly rounded one. It is better to fit the clip so the sharp edge is resisting and load. If you are fussy, you are likely to do the same thing with washers, too. But mainly for appearance rather than safety.

Cheers, Tim

Edited By Tim Stevens on 12/04/2023 17:43:45

The two cones may well serve as formers for sheet metal bending or forming. Or as parts of a spinning lathe (no, not a lathe which is spinning, but for the operation called metal spinning where you start with a flat circle of sheet and press the metal as the former spins, in stages, to produc cups, headlamp reflectors, etc). The thing with the big tommy-bar looks like a spanner to turn, or hold, a splined shaft while you do things to it, or perhaps with it. It might be used to control the chuck which holds one or other of the conical tools.

Was anything else included in the same job-lot?

Cheers, Tim

And to reduce the chance of rust forming from now on, get yourself a dehumidifier, and run it on days when it has been cold and is warming up. Collect the dribblings from the de-humid, and use them where you might need distilled water. And keep the doors etc shut.

Cheers, Tim

Did no-one else notice the following, above?

Apply the solvent to the back side

Cheers, Tim

There is no cure for fatigue. Once the failure has started, there is very little chance of repair - except renewal, which is not repair sensu stricto ( or should it be senso strictu?). The problem is that fatigue works by extending a crack - and the crack is the source of further failure. It may be possible, in some cases, to remove the crack completely including the material on both sides, and filling the space with new material which is integrated (not just glued or stuck) into the original. Perhaps possible with a steel component restored by welding, but even then there are likely to be future problems with the weld not being the same as the original metal, or the heat of the weld affecting the condition of the surroundings in various ways.

A cloth hinge, if you can manage it, is likely to last at least as long as the original plastic. But the glue might not.

Cheers, Tim

Dave warns against 'fabricated' pulleys, but what exactly does he mean by it? To me, fabricated implies a built-up structure - the Forth Bridge is fabricated from steel tubes and rivets. But the pulleys we need (I think) are one-piece, whether cast or forged or turned from an extrusion.

Experts always know what they mean, but they need to remember that we are not all experts at what they are expert at.

Regards, Tim

The silver-solder fluxes I am familiar with are all based on boric acid. Some of the patented recipes include salts which enable the glass-like residue to dissolve quickly in very hot water. Otherwise the borate glass will dissolve slowly in dilute suphuric acid (used on sterling silver, but not so clever for steel).

Even if you don't get it all off, it will (in my experience) weather away and rub off - looking like whitish mould in the process.

Another way to remove glassy deposits which have melted to a metal surface (including real enamels) is to heat the object to a dark red, and sprinkle saltpeter* on the glassy surface. This results in a more liquid glaze which includes nitrates and so (when cooled) dissolves in water.
* Potassium Nitrate - use a bit more than the same volume of it as the deposit to be removed.
[Or if you are making your own fireworks, ask for Nitre - it's the same stuff but an even older name. If you use the scientific name the next question will be 'What do you want it for, sonny?']

Cheers, Tim

My claim for electricity was based on an understanding that petro-chemicals were on the way out. A process that produces carbon dioxide as a byproduct is not helpful, but one that produces oxygen is exactly the opposite. And I was relying on details from Orkney and and Norway, where electrolysis is used.

Tim

Can I suggest that the use of stainless steel may be contributing to the problem? It is known (from real life experience, mainly) that unlubricated stainless can gall - pick-up into a mess that sticks the two surfaces together, rather than (as you hoped) produce a nice sliding surface. So, any idea about a return to original should include valves made of the original stuff.

Cheers, Tim

First for Old Mart - yes, the main process for 'producing' hydrogen is electrolysis.

Now for the main argument.
Hans has carefully set out the theory - how much energy is needed. Good science. But then he goes on to ask how we could improve on that figure. What he seems not to appreciate is that science is about what happens. No fairy stories, if you do this, you get that. So what we could reasonably be asking, instead, should be, I suggest:
Ok, what do we need to do to get as near to that theoretical figure as possible?

There is another question: do these figures represent the end of the road for progress in this matter? Well, perhaps not, but that is again what science is about. You work out other possible theories, and you try them out, and you calculate carefully what goes into the process, and what comes out, and you hope that the answer is better. And if you succeed, (and only then) you publish your results*, with two objects in mind - first, you hope that others will try your new method, and come up with similar, better results, and benefits all round. Second, you hope someone will get together the finance to make your new process available more widely, so that money, and other benefits, will accumulate for them, and for you.
* and at this point, you need to consider a patent.

If, however, you 'invent' a new process which you claim to be much better, and don't show your working, and if you do, you get the sums wrong, you are no better than a million others who have convinced folk to change their ways, and no real benefit results. Whether it is called snake oil or religion, the outcome is the same.

I don't believe in fairy stories; neither should you.

Regards, Tim

Martin

It could, perhaps, be a flat file with a safe edge on the left, designed for a chap with a safe right-edge file who has not worked out how to turn it over ... ?

Cheers, Tim

Yes, I agree that left handed files would be handy - even for us dextrous majority. But even more useful might be upside down files - with the cut stroke away from the handle. Then you could take the burr off the back edge of a strip without torning it round in the vice. Other uses are also avalable.

Cheers, Tim

Martin - your argument is similar to the one that reminds us that English folk are always a bit clever because they have to cope with such a silly language. I'm English so I am sure it is correct ...

Tim

Edited By Tim Stevens on 09/02/2023 18:08:37

Isn't it odd that lefthandedness led to insulting adjectives, and ability to use either hand, a compliment?

Do I need to explain? Well, even-handed folk are regarded as fair and reasonable, and left-handed iones can be sinister, cack-handed, gauche, etc. Other adjectives are available.

Cheers, Tim

The advice I had from a maker's rep (Unbrako) in the 1970s was that socket headed screws and bolts are not made from 'ordinary' R grade or 8.8 steel, as the stresses in the socket would be inclined to open it out. His advice was 'Socket heads = high tensile'. And he was not trying to sell me anything.

Cheers - Tim

Rod is right - thanks. Anything that was even slightly heavy went by boat. Look at the placing of the major Roman towns in the UK - almost every one is as far up the river as the boats could get. And of course, that was where a river crossing developed, often a ford to start with, sometimes a floating bridge.

Exeter, Dorchester, Winchester, Chichester, Colchester, Gloucester, Chester, Lancaster - and that is just settlements still carrying names based on Roman activity there.

Cheers, Tim

I invite Bazyle, and anyone who thinks he is right, to offer evidence of the claim that there were villages and towns all linked by roads, before the Roman invasion.

Tim