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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: Accuracy of Hand Drilled holes
09/10/2021 10:43:12

Marking out and drilling by hand? I wouldn't even try.

If this refers to the Antikythera mechanism, why assume it was done by such primitive means? The designer of the thing knew more than a bit about maths and geared mechanisms. Therefore I'd expect a dividing engine would be known technology, or at least imaginable to the designer, and a drill bush in a stand would facilitate accurate drilling. Those folk were SMART!

Thread: EMCO FB2 Head Unit
07/10/2021 21:19:13
Posted by Bountyboy on 07/10/2021 11:08:30:

...

The manual does shows two methods of mounting and dismounting tooling: the use of a draw bar or arbors with flat tangs but I appreciate the possibility of the taper spinning and scoring the bore. Best to play safe and modify the MT-JT arbor as you suggest.

The subject of tangs and their purpose has come up on this forum before. They are a safety back-up, to prevent the arbour spinning (hopefully!), should the taper lose grip. In drilling machines - but not milling machines - the tang engages a slot in the spindle, so the arbour can't spin. The spindle is provided with a slot in its side, so a tapered drift can be used to push the arbour out, the drift bearing on the end of the tang. Modified arbours are a GOOD THING!

Edited By Kiwi Bloke on 07/10/2021 21:25:35

07/10/2021 21:09:48
Posted by John Haine on 07/10/2021 10:12:39:
Posted by Kiwi Bloke on 07/10/2021 00:55:58:

Just in case you don't know, make sure you get a 'motor run' capacitor, not a 'motor start' capacitor. The latter are electrolytic and will fail after very little running time.

Edited By Kiwi Bloke on 07/10/2021 00:57:36

Um, start capacitors are highly unlikely to be electrolytic since the latter get very hot and are likely to explode if connected across AC. What if the motor was jammed when you start so the starter switch doesn't disengage?

What I said is correct. Start caps are indeed usually low-ESR bipolar electrolytics. They will indeed heat up, when in circuit, which is why they are applicable to low duty-cycle applications only. If the starter switch were to jam closed, the cap would overheat and I'd also worry about the start winding burning out.

07/10/2021 09:34:57

Forgive me if you know what follows already - it's not clear from your posts what your level of knowledge and experience is, particularly with Emco gear.

Please do make use of the self-extraction functionality that the screwed cap on the upper end of the spindle provides. I always cringe when people talk about whacking the end of Morse taper tooling to release it from the spindle. And use a draw-bar in the arbour for a drilling chuck. This may mean having to modify a MT-JT arbour, by removing the tang and drilling and tapping for a draw-bar. A previous owner of one of my FB-2 heads obviously didn't, the arbour spun in the taper and it's scored. Emco hardened the spindles, so full rectification means grinding. It's a get-around-to-it-one-day job...

FB-2 spindle motors run hot. Don't worry too much. 'Fraid I don't know their max. allowed temp. Probably 60C is OK. Someone will correct me if that's wrong.

Please make use of the horrible little spindle-holding wrench (if you've got it), to hold the spindle against draw-bar tightening/loosening torque. It's tempting to select lowest speed in the gearbox, to immobilise the spindle, but there's a tufnol gear inside, which is known to strip teeth if abused.

The FB-2 is a great little machine, and, if you've seen Joseph Noci's and Graham Meek's work, you'll see that it's capable of excellent results (when driven properly, of course...). Isn't the V10-P the one with fragile electrical switchgear (made from Unobtainium) on the back of the top of the headstock? You might look for a Maximat 11, again another Emco machine capable of excellent results, as shown by Stefan Gotteswinter on YouTube.

White spirit doesn't seem to attack the paint used by Emco, and gets most crud off.

Genuine Emco collets and collet chucks were made by Schaublin. You get what you pay for.

There's no end of good help and advice on this forum - don't hesitate to ask.

Edited By Kiwi Bloke on 07/10/2021 09:38:24

Edited By Kiwi Bloke on 07/10/2021 09:40:01

07/10/2021 00:55:58

Just in case you don't know, make sure you get a 'motor run' capacitor, not a 'motor start' capacitor. The latter are electrolytic and will fail after very little running time. The former are usually metallised polypropylene. They are cheap, and available from electric motor suppliers, re-winders, electrical wholesalers, RS Components, Farnell (now called Element 14 - I think), etc.

Edited By Kiwi Bloke on 07/10/2021 00:57:36

Thread: Turning, Milling and Drilling Speeds
03/10/2021 09:38:36

William, beware that cutting speed tables are based on some important assumptions, but these assumptions may not be obvious. For example, most accessible tables are prepared for industrial use, where machines are more powerful and more rigid, and flooded with cutting fluid, compared to typical garden shed inhabitants. Also, the speeds may be those likely to maximise production, with 'reasonable' tool life (whatever that means), whereas we usually want to be gentler and don't mind taking more time. One could go on, but, in reality, on 'our' machines, what works best is best, and speeds and feeds can't be transferred from one machine and setup to another with any confidence. Use tables prepared for 'us' (The Model Engineer's Handbook, by Tubal Cain [not the dubious American upstart]) as a guide, but don't be afraid to experiment and break 'rules'. And once one starts to use 'exotic' cutting materials, it's a whole new ball game...

Thread: Clock Stand with a difference
03/10/2021 09:22:17

I'm hesitant to suggest a solution, because I think it's well-known, so I suspect I may have misunderstood the problem.

Arrange some form of stand which can carry a dial indicator to bear radially near the top of the column to be tested, both stand and test-piece sitting on a surface plate. The indicator-carrying stand needs to have a second, fixed, elephant-foot-like 'probe', bearing on the column to be tested, as low as possible. The purpose of this second 'probe' is simply to allow the stand carrying the 'probe', etc. to clear the base of the column and to act as an horizontal datum. The fixed 'probe' lies vertically below the indicator's probe.

With the fixed 'probe' bearing on the lower part of the column, the indicator will read out-of-truth as the column is rotated. As you'll realise, a V-shaped end to the fixed 'probe' makes life easier...

Thread: Win 10 back t0 Win 7
08/09/2021 10:25:56

Yes, good point! I hope the fact that Linux is free isn't being disputed. I believe that some businesses buy a Linux OS + support package. I think Suse offered that. The OS is free, the support isn't. Perhaps that's the explanation.

...edit. Must try to type faster!

Edited By Kiwi Bloke on 08/09/2021 10:26:42

Thread: Why do designers do this!!
08/09/2021 03:37:54

Absolutely agree with Nigel B.

Another favourite trick of car design is to put loads of expensive and fragile components right behind the fragile plastic 'bumper' (misnomer), so the whole lot is trashed when granny in a supermarket car park reverses into your car. More spares supplied = more profits. The insurance companies know all about this, but compensate by raising premiums. The consumer doesn't count, once the product is bought.

Edited By Kiwi Bloke on 08/09/2021 03:40:06

Thread: Win 10 back t0 Win 7
08/09/2021 03:28:43
Posted by Peter Greene on 08/09/2021 01:48:21:
Posted by Vic on 07/09/2021 22:09:31:

As of last month Linux market share is 2.4% according to this.

Even the "Unknown" OS managed to garner 3.6% surprise

Well, what does 'market share' mean? If it's anything to do with the amount of money paid to buy or rent an operating system, it's not surprising that Linux is at the bottom - it's free!

07/09/2021 12:34:32

It's been said before - countless times. Regain control of your PC: install Linux.

If you must retain Windoesn't, you can install Linux so your machine can boot into either operating system.

Thread: Wringing gauge blocks together... in a vacuum
07/09/2021 12:29:59

I'm sure I've read that gauge blocks left wrung together become very hard to separate, and it's taught that it's bad to try to pull the blocks apart - they should always be slid apart. In both cases I believe that the surface can be microscopically damaged. I suspect that the microscopically thin oil film, which would be very difficult to remove, at a molecular level, and any trapped gas molecules act to make separation easier, by preventing cold welding-like effects. Surely inter-atomic or inter-molecular forces are responsible, when such welding-like behaviour occurs.

Thread: UK fires up old coal power plant as gas prices soar
07/09/2021 12:18:11

'Clean, Green New Zealand' [laughter] has just burned more coal than ever before. It seems that we're not alone. There's really no hope, while 'the economy' is all-important.

Investment tip: invest in coal mines!

Thread: RAF to give up flying planes.
07/09/2021 12:12:22

Jet pilots - who needs them? Fully-autonomous drones can do the job. Safer, cheaper. What could possibly go wrong?

Thread: Converting fractions to decimals
19/08/2021 10:34:48

OK Dave, I'll bite!

Good, provocative thoughts. I thought the subject deserved its own thread, so I've started one, in the Tea Room.

Thread: Clinging to the Past
19/08/2021 10:30:50

SOD's post in the 'Converting Fractions to Decimals' thread contained "The history of engineering shows new techniques always win and it's a bad mistake to cling to the past. Discuss!" So I thought I would. It warrants its own thread.

I'm sure this quote isn't entirely correct: surely some techniques have blossomed and then withered. But it feels like it's correct: change is always happening, and seemingly accelerating. Often I wish it would stop. Why do new techniques seem to win? Are they always better, or just fashionable, or quicker, or cheaper, or is it because they are marketed more sucessfully? In today's hyped-up, media-driven society, new is good and old is so, well, last year.

I will continue to cling to the past. It's where I've spent the entirety of my life so far. I know about the past, and feel familiar with it, but I'm distinctly fuzzy about the future. I like manual machine tools and I like scraping, old techniques that keep delivering the goods.

Change for change's sake is foolish. It's so easy and cheap to mess around with software that functionality can be changed and added to computer-driven systems almost at a whim. Doing something just because it can be done is no justification. Software-driven systems are surely to be included in SOD's 'new techniques'. I hope they don't always win, or the human race is done for!

Over to you...

Thread: Dipping a toe in TIG - what do I need (apart from skill)?
09/08/2021 08:18:43

I'd go for the largest Ar bottle you can afford - you'll end up getting through quite a bit of gas because it sounds like your machine may not have sophisticated gas control. Anyway, you're going to do a lot of practicing, aren't you?

Also needed: auto-darkening helmet; proper TIG gauntlets - sensitive enough for good filler rod control; a few Kg of filler rods, of various sizes; tungstens; tungsten grinding facilities.

Your machine may start best using thoriated tungstens. But thorium is radioactive, and, although from a distance the electrodes pose no hazard, inhaled thorium dust is very nasty. If you're going to have to grind, you must be careful about the dust. Because of the radioactivity problem, and with the availability of high frequency starting, there's been a move away from thoriated tungsten. Lanthanated or 'rare earth' tungstens are fine for most steel work.

The grinding wheel used for tungsten grinding should not be contaminated with anything else. You can get away with an angle grinder and suitable flap abrasive wheel. Hold the grinder, wheel upwards and horizontal (in a vice?) and hold the tungsten in a slowly-rotating (cordless preferred) drill.

Gas lenses are good! They allow less gas to be used and facilitate access to the work. Find out all you can about them. No real need not to use one.

Look at Rapid Welding's web-site. They carry CK torches (and everything else you'll need). It would be a good idea to get the feel of a torch before you buy - you need something over which you can have fine control. The smaller CK torches are nifty, and come with a very flexible hose that doesn't try to take control of the torch's position.

Thread: EV Charging Hacks
05/08/2021 12:09:33

The point wasn't so much about the intrinsic fire risk of EVs, but the suggestions about how and when they should be charged, and whether this should be unsupervised, etc. Another point, not addressed in the link, is all the difficulties first responders face when attending an EV 'incident', including a fire.

Thread: Pythagorean Triples in Babylon !
05/08/2021 12:03:44

Interesting discovery. The 'second tablet' seems to be a 'look-up table' for a limited range of triangle configurations, suggesting that the end-user wouldn't have understood the geometrical theory and couldn't work out general-case problems. Perhaps the theory wasn't known, and all that was available was empirical knowledge. Then along came theoretical understanding, with Pythagoras - although it's now suggested he merely popularized the theory.

05/08/2021 11:26:15
Posted by Ady1 on 05/08/2021 10:58:33:

A lot of the problems early civilisations had seem to stem from the number systems they used and the amount of brainpower required to translate and visualise those number signs into meaningful information which could be used to generate even more meaningful information into processes and conclusions

Coding for computers has the same issue and various attempts have been made to simplify the visual result of all the bits of electronic lego in a coding structure, I suppose electronics had/has similar issues

Once you simplify it into the correct format the average human brain fairly romps through the subject matter

A simple example

They are both base 10

compare doing long division or multiplication in roman numerals and decimal numerals

Edited By Ady1 on 05/08/2021 11:03:37

Yes, absolutely! Good points! Personal realization was trying to get to grips with musical notation, as an adult. It's a disaster! Usually, of course, it's something that children, not adults, grapple with, and kids will accept anything... The crazy system we have is the fault of the Catholic church. There are rational notation systems out there, but they'll never catch on: there's no point battling against the traditional system's self-renewing user base.

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