Member postings for Tim Stevens

I wonder - was your 'rotating drum assembly' possibly made of brass? Very inclined to grab, brass is, pulling the tool into the work. Just a thought.

To stop this effect, take the sharp edge off the tool with a fine stone - 5 to 10 degrees of negative rake - taking off as little as possible so you can restore the tool for steel. Or, keep a few tools for brass, ready stoned, if you use it regularly.

Cheers, Tim

Well, at least you have a range of colours available. Rouge is red, magnetite is black, so a mix can supply browns. And if you allow a bit of harmless carbon-dioxide into the mix, the whole range of ochres.

cheers, Tim

One factor which needs to be considered, too, is the range of conditions in which the bonded parts will exist. Several clever adhesives are modified (or destroyed) by heat or cold, vibration, or by solvents, including everyday cleaning chemicals. Advice offered in the absence of detail like this may be nugatory. Or worse.

Cheers, Tim

The VSCC has a considerable number of A7 members. For a pre-1931 car, the VSCC has a 'Lightweight Section' which has around 50% of A7 entries in its events.

the VSCC is currently based in Chipping Norton, but their magazines go world-wide. Vintage Sports-Car Club, if this helps.

Cheers, Tim

Edited By Tim Stevens on 31/03/2022 12:13:23

SoD says (a few posts back) -

Cause for concern that large numbers of people ignore evidence, preferring hearsay, pseudo-science, outdated information, vested interest, or political dogma.

Just think about this for a moment. In the UK we have a head of state who is by law also the leader of a belief system which is based entirely on documents dating (we are told) from 2000 or more years ago, and which contradict themselves. When you ask what evidence there is to support their beliefs, we are told 'You don't need to have proof, what you need is faith'. This seems to mean 'If you really believe it, it is bound to be true'. And isn't this exactly the same as the problem SoD is describing, and which causes us all so much grief?

Regards - Tim

I am loth to query a statement by a moderator, but here goes:

Jason - I wonder if it would help reduce confusion if the coating used on lots of cutters were referred to as TiN, rather than TIN? Tin is a soft metal, used for coating copper pans in the kitchen, and no use at all in resisting the pressure and friction of machining.. Titanium Nitride is a much tougher material. Using the term in this way also encorages people to realise how chemical formulae work.

Regards, Tim

hello SoD

As an ex-quality engineer, and a quality conformance engineer, I am sure I remember what quality means to an engineer. It means 'Compliance with the specification'.

Of course, the term is used without any reference to a spec, and therefore is a very useful term for marketing. Whether marketing ever uses terms which are useful to anyone else is not borne out by my experience.

Cheers, Tim

I wonder - is the hobby shop here intended to be a retail business dealing with hobbies in general and/or steam or engineering in particular, or is it a new collection of machinery and work stations for a range of hobbies or one or two particular hobbies, or what?

From the discussion, after five responses, it starts to become clear that the general conclusion is hobby = OP's hobby, just for him, something model engineering related. So, my first thought was completely wide of the mark. But I do enjoy guessing games - more please.

cheers, Tim

PS there is another odd effect with cleaners which evaporate quickly - they cool as they evaporate. And if this is quickly enough, the cooling is significant. Enough, on a damp day in an English shed, to cause a film of water to settle, causing rusting.

Tim

White spirit is a major constituent of many household paints and varnishes, as well as brush cleaners. It is used because (inter alia) it does indeed evaporate. But it does no go as quickly as petrol (gasoline) or alcohol. Patience is, I was told by my grandmother, a virtue, but I never stood around long enough to find out.

Cheers, Tim

Confusion can arise - especially in steam circles. an indicator is a device to measure (on a dial) and record the steam pressure in an engine cylinder as it produces power under load. A calculation then gives the 'indicated horsepower'. But that is not what is required here.

If you ask a vague question you are likely to get a vague answer - sorry.

Cheers, Tim

And - if you sell, you will need to know exactly what you have got, and what if fits. A box of assorted gears is almost worthless - bought (if ever) in the hope that something in the box might be useful. But a box of change gears for a Myford lathe, complete with metric conversion gears, for example, is going to appeal to several of us.

Secondly - put pictures up here by all means, but if you want us to identify things, put a letter or a number with each item, and we will know what we are describing, and so will you.

Cheers, Tim

I am sure I have seen convincing tiddly rivets produced by using a blunt centre-punch at the back of the item, and on the other side, a sharp-edged hole. Best arranged, I guess in eg an old* bench drill with a mallet to knock on the top of the spindle.

* or a new one of course. Some bench drills, new or old, are fit for little else.

Cheers, Tim

Please don't worry too much over what things are called. If you do, you will never be able to cope with brushes made of solid carbon blocks, points which are flat, etc etc.

I suspect they were called end mills, originally, to distinguish them from milling cutters which look like circular saws but thicker.

Cheers, Tim

Could it be intended to turn the ragged end of a bar to a nice peg - like an integral dowel?

The rails of country-style chairs include lots of such pegs, and it would speed up production if they were all the same size, automatically.

But perhaps not ...

Tim

I found it easy to make one - using a length of round bar (20mm dia +/-) to which I bolted a flat steel plate with a few holes. In use, the bar is held in one of the table slots, or in a V-groove support or a pair of V-blocks. The 'far' end of the plate is supported by a small screw-jack and adjusted to the required angle. This is checked using a dial gauge fixed on an arm under the milling machine head, and this check allows me to adjust the rotation and the jack height to be sure that the plate surface is parallel with one axis and the correct angle to the other axis (either way round to suit the job). A simple calculation relating distance moved horizontally with increase or decrease in height of the gauge saves a lot of faff trying to measure angles in degrees. the last part I made was a steering support for a pre-war Bentley and I was told it was 'better than the original.'

Much of my work involves one-off machining, and as a pensioner I need not look too often at the time spent, so something like this meets my needs at minimal cost. Whether it will work for you, only you can say.

Cheers, Tim

Hello Hopper

Yes, when they are in a straight line makes sense, in theory. But how do you tell, from the engine in front of you, when they are indeed in line? You can certainly measure the piston position, but where is the crankpin when the piston is furthest up? Or, when the most significant bits of timing (ignition or valves) are around TDC rather than BDC, is that the most relevant place to measure from?

Of course, if you knew what the factory did, easy-peasy, but when the engine was made in a factory bombed in WW2, what chance?

cheers, Tim

Edited By Tim Stevens on 15/03/2022 10:54:19

If it did hydraulic it would be a good idea to check the lengths of the relevant head studs/bolts, and the condition of the threads in the various bits affected. And even if the relevant rod 'looks ok' check its length.

The idea of offsetting gudgeon-pins (wrist-pins) is quite common, as is the idea of offsetting the cylinder bore to the centre line of the crank. This latter is called a desaxé design, and the word has three syllables, not two.

Those of a mathematical bent might care to think how such a design affects the calculation of capacity. And how the valve timing can be set when the two dead-centres are not 180 degrees apart ...

Cheers, Tim

Anyone living in, or visiting France, might find it useful to know that their burning alcohol is made from rubbish brandy, and has a much nicer smell than british Meths. It is sold at builders merchants and DIY shops in litre bottles.

Cheers, Tim

The best size for mending a 22ct wedding ring is the smallest, and if you want to melt the tarmac across your drive, the biggest. obviously.

Or, more realistically, it is the flame size and intensity which counts. So, work out what you will need to do with your outfit, and get a range of sizes. Not every one in the catalogue, but three, perhaps. And when you need something especially delicate, or beefy, consider adding another.

You are also limited by the size of the adaptors, the cylinder connection, the pipework, and - yes - the temperature. On a cold day, the gas (liquid in the cylinder) evaporates more slowly, limiting the max output.

And don't knock your cylinder over - it is not clear to me how a pressure regulator will stop liquid (at the same pressure) from flame-throwing.

cheers, Tim