Member postings for Andy Stopford

I think some of them are spheroidal graphite cast iron, so should be no problem to modify.

Unless they've changed the recipe, Waxoyl can be cleaned off with white spirit. It's easier in warm weather.

I doff my cap to you, sir. I've always thought it would be pretty tricky making a full-size pump element, let alone 2mm diameter (and with a Proxxon!).

I think part of the problem with constant pressure combustion was that it couldn't be hurried, and so was only (sort of) feasible in very large, slow running engines. Herr Diesel, aiming to use the Carnot cycle, originally intended that his engine should use isothermal compression (realised by injecting water into the cylinder), and isothermal combustion. It would have no cooling system, in fact the cylinder would be insulated. And it would also burn coal dust.

Unfortunately theory didn't translate to a workable engine (partly due to the extreme pressures that would be necessary), so Diesel omitted the isothermal compression, and after much experimentation and discussion with his team, ended up with a practicable cycle that used isobaric combustion. Modern, high speed engines seem to have a combination of constant volume and constant pressure phases.

I have a vague memory of someone (Tim Hunkin maybe?) sending rudimentary faxes to a mate by converting their lathes into fax machines. I have never used a fax machine, but should the need arise, my lathe awaits.

It wasn't just Germany who tried diesel aero-engines; the Americans, amongst others, also gave it a go, e.g.

http://www.enginehistory.org/Piston/Diesels/Ch3.pdf

Most of the contemporary reviews of these machines seem to have been very favourable and its not that clear why they never found wider favour, except perhaps that the 2nd World War came along with much emphasis on the highest possible performance, and subsequently gas turbines clearly became the way to go for all but the smallest engines.

Napiers though didn't let this get in the way of trying to develop a truly wacky diesel based power plant:

https://en.wikipedia.org/wiki/Napier_Nomad

Eric "Winkle" Brown flew one of the Junkers-engined aircraft (I forget which one) and reported, slightly surprisingly, that it was smoother and quieter than a comparable petrol engine. He didn't care for the smell of the exhaust though.

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re. the subject of this thread - that's a fantastic piece of work Roger, was there any special trick to making the pump plunger?

From my (limited) experience of doing this, the problem is not the cutter working its way out of the chuck, but the taper (JT, or similar) letting go so that chuck and cutter fall onto the workpiece or machine table. Not good, but unless it falls on your foot I can't see it being hugely dangerous, and pretty unlikely to happen if used for very light cuts only.

Mine is the conical burr type - much more durable than the spinning blade kind; herewith some pics:

I'll have to try growing a coffee bush, don't think I'll bother with the civets though (still, don't knock it till you've tried it).

By the way, bought coffee is never ground fine enough for commercial espresso machines - the spring generates pressures of 9 - 10 bar when the handle is released, enough to blast the water straight through coarse ground coffee. To get optimal results you have to adjust the grind for individual samples of beans, and be ready to whip the cup out from under the spout before the bitter "tails" come through at the end, i.e. you have to be geeky about it, but then if you weren't, you wouldn't be reading this forum...

Edited By Andy Stopford on 17/09/2022 17:11:31

I'll put a photo up tomorrow to give an idea of what it looks like, and the size

Oh dear, it's put on a lot of weight, or at least bulk, since they made mine, even though it does seem to be the same thing under the skin

I have an older version of this:

https://www.dualit.com/products/coffee-grinder

Pricey, but still going strong after 20 years' daily use. It's a burr type and produces the fine grind required by my commercial espresso machine.

Although a faulty speedometer is an MOT failure it is not actually tested, unless the vehicle is being road tested (usually only necessary when the brakes cannot be tested on a rolling road).
If the speedometer is not present on vehicles for which it is mandatory, or obviously inoperable, then it will fail.

An illuminated ABS warning light is a failure (as are engine and light warning lights - the latter can show if LED bulbs are used to replace old-school filament bulbs).

The testers' manual can be found here:
https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles
It's worth looking at if you get a failure which seems incorrect, or you're taking an old or unusual vehicle for test.

Thanks chaps, steel for the crankshaft gears and CI for the others sounds like a plan. The ones Jason shows look like a pretty decent result from the cheap cutters - I'll watch out for them not running true

I'm building the 1" Minnie and am going to make the gears myself.

The book suggests buying steel gears, but I was wondering whether cast iron would be easier on my Cheapo Chinese gear cutter set. I haven't tried them yet, but I've heard they tend to wear quite quickly (the cutters that is). I don't want to use brass (or plastic!) on appearance grounds.

Has anyone any thoughts on this?

With the cutter arranged as in the photo, the spindle should be rotating ant-clockwise, and the table should be fed from right to left, i.e. against the cutter rotation. This is conventional milling.

If the table is fed from left to right, you are climb milling. This will tend to draw the work into the cutter, with the cutter trying to climb over it, hence the name. To climb mill you need a very rigid machine with minimal backlash in feedscrew and nut. It has advantages, but best avoided until you have more experience.

Have you tried using the side and face cutter in the background? These are far less fragile and demanding than slitting saws. Try taking a light cut with it, say about 0.25mm, at the slowest spindle speed available, and see how you get on. If you get nasty graunching noises check that the table slides are correctly adjusted, and the unused ones are locked. If all goes well, try deeper cuts.

I'm just starting a Minnie build, beginning with the boiler.

I've seen a number of comments to the effect that the water pump does not work due to heat flow from the boiler to which it is directly bolted.

Some people suggest moving the pump to the hornplate, but I already have the casting and the angled part of it means that it can only really be fitted ahead of the hornplate. I'm not sure an extension of the hornplate would be rigid enough to support it, except maybe with some strengthening flanges.

Alternatively, I've seen suggestions to use an insulating gasket between boiler and pump - has anyone tried this, and if so what material did you use?

Are there any other ways of getting the thing to work?

I suspect that "PILOT'S INADEQUATE VISUAL OUTLOOK" is almost certainly an implication by the investigators that the pilot's monitoring of his visual environment wasn't sufficient (in Britain the word used is Lookout), rather than that he had an eyesight problem (he was required to wear corrective glasses). Quite how they knew this is another matter - this investigation report seems particularly short for a somewhat inexplicable fatal accident, with, for example, no hint as to what height the aeroplane might have been at.

There is no mention of balloon fragments entering the engines (or any other mechanical malfunction), so this idea may have been a product of over-active journalistic imaginations in the LA Times.

Edited to remove smiley

Edited By Andy Stopford on 15/08/2022 20:24:46

A four-way toolpost has slots for four tools, but you can very rarely actually use all four slots, since some tools need to be arranged pointing in conflicting directions (this is hard to describe but becomes all too apparent when you try to load the selection you want). The tools not in use are also perfectly positioned to take a chunk out of your hand if you brush against them while trying to set something up in the chuck.

Personally I would give a QCTP high priority amongst 'non-absolutely essential' accessories, they make life so much easier and you don't have to buy all the holders at once - some suppliers give free carriage for orders above a certain value, so adding an extra holder can take you into the free category allowing you to convince yourself that with its purchase you are actually saving money.

I've got one of these; I've found it to be very fussy about feed and speed. My lathe has variable speed control so I can twiddle the control knob to find a speed that works. The feed needs to be pretty brutal - anything less and it will chatter badly and the swarf comes off as a powder. When you get it right, it works well, but most of the time I find an HSS blade less hassle.

edit: I think the insert on mine is different - it has a shallow groove in the top, which I can't see in your photos, and its single-ended.

Edited By Andy Stopford on 03/08/2022 21:21:52

I also found that the effect was considerably more powerful if one of the pads became unplugged or fell off, no burns though.

I bought it when I had killer sciatica last year, and it made my evenings much more bearable (sitting down was when the pain was worst). Martin's one sounds similar - I tried all the different settings at first but settled on the basic one at about 2/3 power and restarted the thing whenever it timed out - just having it running was more important than the level, and using maximum power definitely falls into the more... adventurous category of use as mentioned by Andrew.

Well, it took about two weeks to turn up, which is a bit rubbish considering that they charge you a quite unjustifiable £4.99 for the privilege (a charge not immediately obvious until you've gone a fair way through the ordering process)

As for the thing itself, it's not bad, quite versatile and it's well made, though a the locking screws are a bit fiddly - I might make new ones with larger heads.

I can't see any strong case for a smaller version - I think it would probably be unusable if significantly smaller. On the other hand, a larger version might be handy if you were doing lots of sheet metal work.