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Member postings for Kiwi Bloke

Here is a list of all the postings Kiwi Bloke has made in our forums. Click on a thread name to jump to the thread.

Thread: Emco Compact 5 Modifications
16/05/2022 06:55:10

Hi Gray. Inspired and inspiring! When I saw your post announcing your intention to down-size, and to concentrate on the Compact 5, I was tempted to ask facetiously whether we would be seeing a full screw-cutting gearbox, with leadscrew single dog clutch for it. I didn't because downsizing decisions are too often the result of adverse circumstances, and I certainly didn't wish to be insensitive. However, it seems you're well on the way to elevating this machine from near-toy level to Serious Machine status, so perhaps the question is now part-answered... I'm sure we're all going to be fascinated by developments.

It seems to me that the Compact 5 has serious design defects, predisposing it to problems resulting from wear, that warrant attention, perhaps before embarking on complicated enhancements - well, that's true of my machine, at least. Have you any interest in re-engineering the cross-slide feed 'nut', which, on earlier machines, is cut directly into the saddle, and is neither adjustable nor replaceable? Also, will we see leadscrew half-nuts and saddle handwheel feed, as (IIRC) hinted at in a previous post?

Edited By Kiwi Bloke on 16/05/2022 06:57:43

Thread: Ambiguous words
12/05/2022 09:06:37

It's about time someone mentioned the apocryphal newspaper headline for the report of an escapee from the local asylum who sexually assaulted a woman in a laundry, then ran away.

'Nut screws washer and bolts'.

Thread: making a Square
12/05/2022 08:53:27

"Very easy to make on a lathe." Hmm. Well, it's easy to make something resembling such a square, but achieving the level of precision that the thing should provide is not easy. And if you really want it to be accurate, as well as precise, it's extremely difficult. That's why folk, even with well-equipped workshops, buy them...

Thread: Sealing Brass?
12/05/2022 08:39:31

Wal, lovely work! Please could you tell us how you made these? Presumably not cast, as traditionally done (?).

[Edit} Oh, just seen your other post. Presumably similar technique...

Edited By Kiwi Bloke on 12/05/2022 08:42:53

Thread: Ambiguous words
30/04/2022 01:55:14

What about words that (recent? American?) common usage has made potentially ambiguous? 'Nauseous' does not mean 'experiencing nausea'. People who use it thus are nauseous!

Thread: Cheap stuff
30/04/2022 01:33:26

C'mon girls, less of the scratching and hair-pulling.

We all like to do things our own way. The sin is to think that our way has to be the right way. Personally, I get a (possibly perverse) kick out of getting things cheap. There's a pleasure to be had from ownership, which is presumably what drives collectors. It's no sin, I try to convince my wife, to accumulate stuff that may get little use, but which nevertheless provides pleasure. She says that's why she keeps me. Most of my gear is top-quality stuff, bought second-hand, for bargain prices.

Thread: uk acme thread suppler
30/04/2022 01:18:17

It's good to see that Halifax Rack & Screw are still going, and now also have a branch in USA. Don't know whether they will still talk to Joe Public, but they were friendly a couple of decades ago... Good luck.


Thread: MEW, ME, RCM&E and Model Boats under new ownership.
10/04/2022 07:13:58

I hope the new owners don't disrupt the magazine distribution team. Beth and her team have been fantastically helpful during the pandamic, and have ensured that I have a complete run of ME and MEW, despite the postal services failing to deliver several issues. Many thanks and a large bouquet to Beth et al!

Thread: O rings
10/04/2022 07:01:49

Thanks for the suggestions, folks. I'll see if it's possible to get more robust O rings, but we have to take what's available here in 3rd-world NZ - a seriously restricted range of engineering stuff in a country without an engineering heritage... I know the rest of the world is but a few clicks away, but I'm old-fashioned, and prefer to shop conventionally.

To clarify: the O ring seals the end of the cylinder to the body of the cylinder, so it's not a sliding seal. There is no true piston seal in this super-crude (but elegantly simple) design (Kiwi engineering at its best/worst). The dynamic seal is located in the removable end of the cylinder, acting on the ram's outer surface. There's also a wiper seal. The O ring sits in a groove in the seal-carrier (the removable end of the cylinder), and seals against the OD of a turned-down section of the cylinder, the seal-carrier being screwed onto the cylinder.

The designers should have given the O ring an easy life, but it's exposed to full hydraulic pressure, including the effects of a bucket-full of soil, etc., bouncing around when driving over uneven ground. Goodness knows what the peak pressures can be. I suppose it's doing quite well, all considered. Ideally, the O ring's groove should be widened, so a back-up ring can be fitted, but that takes time, whereas replacing the O ring takes minutes...

Edited By Kiwi Bloke on 10/04/2022 07:04:19

08/04/2022 01:55:30

O rings, performing static sealing duty, on hydraulic rams on the front-end loader on my tractor fail slowly, apparently by extrusion. The design could have been better: seal back-up rings would probably have helped. Unfortunately, modification isn't practicable. The loader gets abused and treated badly. Unfortunately, my bad behaviour probably also can't be modified...

At present, common-or-garden nitrile rings (2.25 X 0.125 in) are in place. Does anyone know whether a different material might have greater resistance to extrusion?

Thread: Determining/measuring sub-micron displacement
04/04/2022 11:34:51

I hesitate to add more ramblings to this thread, and lower its signal-to-noise ratio. I tend to post late in the evening, after good food and drink - not the best recipe for clear thought. I'm afraid I've muddied the waters by my last post - it's largely based on a false assumption about how this probe works.

Joe, I'll PM you.

02/04/2022 10:15:22

The more I think about this problem, the worse it seems. I think the problem of achieving a tiny, known, controlled displacement has many similarities to measuring such a displacement. After all, a micrometer measures by producing displacement.

But there's really difficult, more fundamental problem, which, until solved, prevents further progress. How does one detect the initial contact of probe to surface, as the probe advances, before the electronic detection occurs?

It gets worse: for the probe to produce meaningful results, its ball-end's diameter must be known (presumably to sub-micron accuracy), as well as the amplitude of its vibration at the times when electronic detection occurs, as well as at initial contact. In other words, the envelope produced by the vibrating ball's surface must be known (again to sub-micron accuracy). Also, to be useful in practice (to sub-micron accuracy), the centre of the ball must be aligned with the machine spindle to sub-micron accuracy. And then there are the standard metrology bugbears of the effects of temperature, air movement, surface contamination, gravity, etc., etc.. It's a horrible collection of problems!

I still think that optical methods might be able to solve more of the problems than purely mechanical methods, but it sounds like very large magnification would be required, so microscopy might be out (oil-immersion objectives don't sound practicable here). What about projection methods?

I know little about electronics, however, a feedback system is described. Can the feedback sensor's signal be used to, for instance, detect initial contact, before resonant vibration is damped by heavier contact? One might hope that the hard ball, clattering against a stiff-enough surface, at initial contact, might produce an albeit tiny, detectable signal, or at least distort (clip?) the feedback signal's waveform.

I can think of other problems, but it seems bad enough already. Glad it's not my problem... Most impressive - good luck!

01/04/2022 09:54:42

I suppose you could start by investigating mechanical or optical amplification, the simplest that comes to mind would be a lever mechanism (causing and measuring the deflection at the 'long' arm) or a rotating mirror, with the scale a long way from the 'action'. The devil will be in the detail, so the pivot will have to be 'perfect' - a flexure, perhaps. Or research the mechanisms used for micro-manipulators. As you might expect, Dan Gelbart has a video which includes flexure-based micro-deflection mechanisms. Good luck: chasing microns is hard...

Thread: Using kerosene to clean ground surfaces
24/03/2022 08:06:39

Paraffin/kerosene will evaporate, eventually, but, of course, whatever was dissolved in it may not. Therefore, there may be a residue left. Either immerse small items in a pot of the stuff, or use masses of the stuff, and wash off the crud with it, or - much preferred - clean with as little paraffin as possible, then wipe down with clean paper or rags, with more clean paraffin, if needed. It has no lasting anti-corrosion or accuracy-destroying property, and the smell will go in a day or so. If you're flush, you could buy odour-free lamp oil, which is a bit more refined (in both senses...). I don't think a workshop smells right without a whiff of paraffin...

Paraffin is a good solvent cleaning agent (for thos things that it dissolves, naturally, including oils, greases, waxes and other hydrocarbons). It's unlikely to damage paint finishes (unlike acetone, for example), and its lower volatility than petrol/gasoline means that it's safer, but also it hangs around so you can remove it along with the dissolved crud. Volatile solvents just dissolve the crud, then flash off, leaving the crud thinly smeared everywhere.

As Hopper and Thor suggest, follow up with something with anti-corrosion properties, or just use WD40, etc, if the amount required is small.

Edited By Kiwi Bloke on 24/03/2022 08:07:28

Thread: Thread-cutting oil
18/03/2022 09:48:49

Stickiness is a problem with some compounds intended for low-speed, hand tool use, and at lathe cutting speeds, they tend to smoke unpleasantly. You could hunt for a lower-viscosity product, or bite the bullet and use a straight cutting oil - with a flow rate sufficient to clear the chips. Yes, it gets messy. Isn't that part of the fun?

Thread: ML7 oiling advice
18/03/2022 09:44:01

Sometimes I think I must be the only person who is reasonably happy with the original type of oil gun, as supplied, new, with my Super 7 in about 1977. It does take a bit of determination, careful alignment and strength to avoid leaks, but it works, if spoken to firmly. Is it really so bad? Anyone else a satisfied user?

Thread: Is this distasteful
14/03/2022 07:40:41

Better, surely, for us to decide for ourselves what we consider tasteful or otherwise, and to act accordingly, than to have others decide for us and legislate, or apply mob rule.

Edited By Kiwi Bloke on 14/03/2022 07:41:25

Thread: How Many People Does it Take to Change a Lightbulb on the Forum?
11/03/2022 22:58:35

...meanwhile, a recent ex-president claims that reports of dead and sick lightbulbs are fake news. Regular washing in dilute bleach will prevent them from getting sick or dying.

Thread: In the murky world of Cookies
11/02/2022 20:34:22

The Chrome browser is another of Google's tools for harvesting data about users. By using it, you are playing Google's game and supplying Google with data about yourself and your activities that you might not (should not) want shared or sold.

Chromium is the free, open-source version of Chrome. It is touted as being more private and more secure than Chrome, but there's still bits of Google in it. It's probably a step in the right direction, but not far enough. 'Ungoogled chromium' is a development of Chromium that aims to remove as much as possible of Google's dirty tricks from the browser. Wikipedia has a page on it.

Browsers are just too complicated, with all sorts of strange functions operating. Even Firefox is suspect. For the paranoid, there are many of its settings that can and should be changed from default values, but it's a little tedious. Remember, if you're 'connected', someone is trying to harvest data from your device, and, unless you take steps, little is done to frustrate them by default.

Also, use a script blocker. You can turn off many of Google's scripts with impunity.

Thread: Emco FB2 mill - weird Z position shift
09/02/2022 23:37:06

I'm a bit wary about contributing again, having made a fool of myself over the spring, a few posts back. The stupid thing is that I knew about the spring, a long time ago, but had forgotten and now got confused. It's an age thing, I suppose, and it's only going to get worse <sigh>.

Chris: yes, I think I understand what you're suggesting, however previous posts have suggested test set-ups which are, I believe, equivalent. Graham Meek and myself have 'clocked' the end of the spindle: it may not be absolutely 'flat', but if it's not quite flat, or if its surface is tilted wrt the spindle axis, any error due to these causes will show up as cyclic errors, or a pattern of deflection that repeats each revolution. That isn't what the original video shows, although, to be pedantic, one has to infer that from the spindle being turned approx. 180 degrees each time, rather than continuously. We could be seeing a cyclic error, but let's be generous to the OP and assume that's not the case.

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