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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: Squealing motor
06/08/2018 11:42:17

I have recently become the owner of a Cowells 90ME lathe. It's about 30 years old, but has been almost unused. It's driven by its original single-phase TEFC synchronous motor. The motor's maker's/ratings plate has been removed. I would guess <1/3hp. It has a capacitor, in circuit all the time (no centrifugal switch), but its value is obscured by paint. The electrical details are hopefully irrelevant, because the problem is that the motor emits a very high-pitched, constant squeal, when run in either direction.

Dismantling reveals the expected construction. One pre-load wavy washer. All is clean - no corrosion, dust or discoloured lubricant weeps. The shielded ball bearings feel 'right'. No evidence of anything rubbing or races turning, etc. The motor feels absolutely fine, when spun by hand. A single oil seal exerts a little drag. Loading the shaft axially and radially, under power, makes no difference.

So, anyone any idea why the wretched thing squeals? I've never come across ball bearings seeming OK, but noisy like this - but what do I know? I doubt that the bearings themselves are at fault. Can shields rub and squeak? I suppose I should replace the bearings, but before that - could it be anything else?

Thread: Myford lubricated with grease
20/02/2018 05:48:21

Alan, why not strip everything down? These machines are simple enough, the manual is good and a wealth of help is available here. If the previous owner was daft enough to use grease, rather than read the manual, who knows what else he's done? You need to find out, and you'll learn a lot about your machine.

I bought an Emco FB2 milling machine, also grease-lubricated by the idiot previous owner. He had put washers under the table logitudinal feed nut. What??? Obviously had no idea of how to align a feedscrew with its support bracket.

Having said all this, provided the grease hasn't hardened and blocked the oil passages, it probably hasn't done much harm. The risk is that chips and crud aren't washed out from the slideway bearing surfaces by frequent oiling - grease 'hangs around', so doesn't seem to need replenishing so often (by the misguided).

Thread: Jock Miller's Taper Turning Attachment.
18/02/2018 20:23:03

If anyone's still having trouble getting their head around the layout of this attachment, here's an 'exploded' diagram (from the Emco V13 manual) of the device that inspired Jock.

Note that Emco chose rollers, rather than Jock's slippers, to follow the 'sine bar'. One roller is mounted on an eccentric pin (9) for clearance adjustment.

I am local to Jock and know him well and really must visit him again soon. If more questions appear here, I'll get answers directly from him and post them - hopefully within a fortnight or so.

Hope this helps.

[Note to Editor - please can you encourage contributors to provide GA drawings routinely for all but the simplest projects, instead of unnecessary instructions on the most basic workshop techniques and photos of drill bits going into metal, etc.?]


Thread: Oiled hardboard.
07/02/2018 10:41:04

A thin layer of smooth-surfaced MDF is worth a try. It can be replaced cheaply. With a rag, rub in well-thinned poyurethane varnish. Rub until the surface seems dry. De-nib with fine abrasive paper. Anoint with as many coats as it takes until the surface doesn't absorb any more - or until you get bored. This waterproofs and hardens the surface. It's possible to get the most beautiful, silky-smooth surface, should you want to.

Thread: Alternative Lubrication
07/02/2018 10:31:55

My experience too. 3-in-1 eventually oxidises to a disgusting sticky goo, as does lanolin, although both are regarded as the answer to a maiden's prayer. The woodworkers love camellia oil. IIRC, Axminster sells it. I've had excellent results from a product called 'Corrosion Block' (it does what it says on the...), from the same people who make ACF-50, which is widely used in the aviation industry. However, ACF-50 slowly evaporates.

Thanks for the info re sodium benzoate - I'll go and sniff some VPI paper - I could do with perking up a bit!

Thread: Security
07/02/2018 10:21:27

Apologies if this has been asked before.

Why isn't this a HTTPS site?

Thread: blueing mild steel
28/07/2017 02:30:40

I've had a quick look through 'Firearm Blueing and Browning', by R H Angier, dating from the 1930s, but still available as a reprint, from Stackpole Books (USA). This is the 'bible'. However, it shares that book's disadvantage of not having an index, so searching is a pain, and I might have missed something. I have found reference to wax being used only as an after-treatment, to provide corrosion protection. Like shoe polish, and the Karate Kid, 'wax on', then 'wax off'...

The book's a bit of a nightmare, because there are so many ways to produce the magnetite oxide on steel, varying from tedious hard work via alchemy to simple stuff. There's little guidance on their relative merits and the chemical nomenclature is obsolete in many places.

Cooking up in a boiling solution of 80oz sodium hydroxide and 50oz potassium nitrate in 1 gallon of water (sorry about the units) is easy and effective - and rather nasty... The desired boiling point is 140 C, and is adjusted by the amount of water. Since the water tends to boil off, you may wish to add more at some time. Beware! The colour develops rapidly. Rinse well, dry and oil. Like electroplating, surface preparation is everything, and thorough degreasing is vital. Solvent degreasing tends to leave residue: hot alkaline detergents are the way to go - and keep your hands out of the stuff!

Thread: Stained cast iron
24/07/2017 12:22:03

I have an iron-bodied Burnerd chuck that has probably sat in its unopened box, in its original greased paper for decades. There's no rust, but the brownish goo has left patches of discolouration on the chuck body. I've had similar staining on Myford accessories - again from the anti-rust grease or Ensis oil, or whatever was used.

Can I appeal to the collective wisdom of the forum participants for ideas as to how to remove this staining? No doubt gentle abrasion would do the trick, but I don't want to alter the existing, pristine surface finish. It would be good to know which chemical treatment works, non-destructively, before experimenting...

Thread: Brown-out Protector project.
13/06/2017 07:15:26

This project originated in the Australian magazine 'Silicon Chip' a few years ago, and was updated recently. The main worry is burning out the start winding of induction motors if the voltage is insufficient to allow the motor to speed up enough for the centrifugal switch to disconnect the start winding. This type of motor is usually rated for so many starts per ten minutes (or similar) for the same reason - to protect the start winding from overheating.

In NZ, and the primitive offshore island to the west, power lines, especially in the rural areas (rather a lot of them...) are above ground. Whenever we have strong winds here, trees come down, often across power lines. We had an impressive brown-out here, a few years ago. One phase failed. Unfortunately, that was the phase supplying the power to the house. Because of parasitic coupling, there was a variable voltage on the live line, between 90V and 130V, if i remember correctly. Freezers, 'fridge and water pump didn't like it at all, but I don't know whether any of them were truly at risk - I don't know what type of motors they have. The really impressive thing was the strange strangled squealing noises coming from the electricity meter(s). I pulled the main fuses.

After that, I thought I'd make up a couple of Brownout Protector kits. They are kitted by Altronics, in Oz. Perhaps unsurprisingly, they are not stocked by the NZ distributor of Altronics kits. Kiwis are risk-deniers... I'm not, so have a stand-by generator!

Thread: MEW 253: Workshop Techniques; Darren Conway
11/04/2017 05:03:23

Oh, wonderful! This is why this forum is solid gold. There's so much knowledge and wisdom around. Thank you Bandersnatch and Bazyle! It has to be RSS, doesn't it? I found physics, pure and applied maths fine, but statistics and probability calculations caused cerebral meltdown. Why are they so counter-intuitive?

Neil, just getting the mag out regularly must be a nightmare. Well done! Unfortunately, as editor, you get to be the focus of all criticism, discontent, etc., whether deserved or not. Perhaps the occasional praise, if you're lucky, makes it all worthwhile. Proof-reading must be a dying/dead art - or just too expensive. Spell-checkers are no substitute. I have the unfortunate ability (disability?) to spot typos and similar errors almost as soon as I turn a page - except in my own writing, of course... It was useful, professionally, but it's a pain. I also wince when I see misplaced apostrophes. I'm glad to see that MEW is better in this regard, under your stewardship.

Whilst MEW is not a learned journal, it aims to be instructive. Let's hope it retains that aim, and doesn't degenerate into a colour-glossy entertainment rag. It has a responsibility to print correct information (wherever possible). That's a big ask.

Thread: Drilling holes
11/04/2017 04:43:27

I meant to ask 'So, what do you do, and why?', wondering whether any consensus would reveal itself. Even without the intended emphasis, I'm glad that it seems to have generated some discussion. Thanks, everyone - can we keep it going?

I take Mr Stevenson's point, but I suppose I'm questioning the advice, probably repeated regularly, throughout Model Engineer's life, to drill with increasing diameter bits (in appropriate circumstances, material, etc.). As HOWARDT says, trying to open out a hole with a two-flute cutter can be hazardous, leading to the problems explained by Bazyle. Drill guides, or something in the toolpost, pushed against the drill, if drilling in the lathe, help, of course. It seems that lack of power, particularly in the days of treadles, might have fuelled the original advice. Is it still appropriate?

Thread: MEW 253: Workshop Techniques; Darren Conway
10/04/2017 10:44:50

Interesting stuff, but I think the lack of proof-reading &/or printer's errors have let the author down. It's good to see this sort of article in the mag, rather than the all-too-common picture-heavy 'Wot I did on me 'olidays wiv a welder/angle-grinder/'eavy 'ammer' type of article that is not very enlightening.

An explanation of the maths in Table 1 would be appreciated - there are undefined variables, and the formulae are truncated. I suspect there should have been a diagram to accompany the table. Also, I'm sure it's just a slip: RMS calculation (as used for the total error calc'n) requires the root is taken of the mean of the squares, not their total.

Thread: Drilling holes
10/04/2017 10:19:17

They say that the biggest fool can easily ask questions the wisest man cannot answer, so I feel no shame asking this...

What is the recommended technique for drilling holes? No, that's not really the question. What's the scientifically correct way to drill holes, and why?

It's often recommended that holes are drilled, using a succession of progressively larger diameter bits. The diameter increment is usually glossed over. OK, doing this reduces the load on the machine (and workpiece), but it has disadvantages. The major one is the difficulty of getting the 'next size' drill to centre, and not try to start to drill a pentagonal, or other non-round hole (for the well-understood reasons). If you ram the bit into the hole, to get it into cut without it dancing all over the place, the sudden load on the bit's corners can break them off.

I tend to drill in only two steps: first, a small pilot hole, around the same diameter as the final drill's web thickness, then the 'finished' size, but I have fairly grunty machines available.

So, what do you do, and why?

Thread: Ceramic(?) board
10/04/2017 09:56:52

Thanks for all the information folks.

I've just looked at my copy of Tubal Cain's Hardening, Tempering & Heat Treatment, No.1 in the Workshop Practice series (pub. Argus Books, 1984) and lo and behold, Sindanyo is mentioned. So that's where I heard about it... Wish my mental filing system was more reliable...

Currently-produced Sindanyo is asbestos-free, but I'll assume that the casing of my elderly furnace contains asbestos.

The furnace's electrical plate says 240V, 23A, so it should cook breakfast OK. Here in the land of the Kiwi, electrickery is harder to come by - domestic wall sockets are rated at 10A, although 15A sockets are sometimes fitted in garages, etc. Wiring regs are different from UK - power circuits are radial, and most houses have many power circuits, each fed from a fuse or circuit-breaker. Joe public isn't allowed to do much in the way of wiring, unless it's 'signed off' by a professional sparkie. I'll probably have to arrange a dedicated feed from the fuse board for the thing. Oh well, if life were simple, we wouldn't mess around with this sort of stuff, would we?

14/03/2017 09:59:35

I have an old Gallenkamp muffle furnace. The outer casing is made of a dense manufactured board, which contains glistening material, possibly mica. (Hope it's not densely compressed asbestos...). I'm sure the name of the stuff is somewhere in the back of my head, but it's rather cluttered in there, and finding things keeps getting harder...

Several ventilation holes, approx 1' dia., have been machined through the board, showing that it machines well. It seems that various fittings are secured to the casing by screws, apparently tapped into the board. I now want to remove some of the screws. Some come out OK, others are reluctant. I suppose, if they are in tapped holes, the hole's thread will strip. Well, that's if I'm lucky - one screw sheared off...

The questions are 1) Any idea what this stuff is called? 2) Does it destroy taps, because of abrasive content? 3) Might Helicoils work?

Thread: Machine tool paints
15/09/2016 12:01:42

Nicholas Wheeler makes some good points. I'll have to re-think some of my prejudices. However, I still don't want the hassle of protecting myself from isocyanates.

Hammerite? No thanks - hated the stuff, both original and politically-correct, emasculated versions. The original thinner (a now-vilified chlorinated hydrocarbon, if I remember correctly) was too useful in the 'shop to waste on the ghastly paint.

If I were back in 'the old country', I guess I'd be trying Tractol, but I don't think it's available here in NZ. Sparex tractor paint is available, however - anyone know anything about it? We enjoy(?) a very restricted choice of many things here. (Thank goodness the craft beer movement is really taking off, so the choice of beverages is much better now!)

No-one's yet answered what the traditional materials would have been. Some of the old machines I've dealt with seem to have massively thick (original) paint, which is hard and somewhat brittle, and comes off in large flakes, rather than peeling off. Would it have been simply many coats of a tough type of alkyd paint?

14/09/2016 10:01:43

I've been following, and admiring, Damian Noble's account of his Senior rebuild. Very impressive!

These days, at least in NZ, and I'd guess worse in UK, it's getting difficult to get hold of old-fashioned paints containing the not-quite lethal solvents we loved to breathe in. 2-pack polyurethanes and epoxies are nasty, expensive and also difficult for privateers to get. Myford's exhibition finish used Trimite polyurethane, from memory, but I was told that the stuff wasn't available to the public.

Eventually, I intend to rebuild some old machines - some from WWII era - and would like to mimic their original finish. They will be used, so the paint must perform well too.

What were the traditional materials used for machine tool painting, say 40+ years ago? I assume they would be some form of alkyd resin paint (= oil-based enamel?), but these can be pathetically fragile. Presumably there were tough versions available. What filler/surfacer would have been used on castings? What primers?

If it's pointless trying to source semi-obsolete paint types, what would you suggest? If there are any Kiwis out there, where do you go for a good selection? Mainland paints in Chch looks promising; anywhere else?

Thread: How should one protect ferrous tools?
14/09/2016 09:38:53

...oh, and another thing. 'Hydraulic oils' typically contain anti-foaming additives (not relevant here, of course) and corrosion inhibitors. Esso Nuto H32, or equivalent, as advised for Myford lubrication (but not slideways), is a nice oil to have around the 'shop - light, and suitable for general purposes. Automotive engine oils typically contain detergents, which messes up their water-displacement properties. They are not good for corrosion protection, although no doubt there are exceptions. I believe that automatic transmission fluid is OK - perhaps it's similar to an hydraulic oil.

14/09/2016 09:30:02

ACF-50 is indeed excellent. Even better, I think, is the imaginatively-named Corrosion Block, from the same manufacturer. It's more viscous than ACF-50, and hangs around much longer. I believe that ACF-50 slowly evaporates. Just a wipe with a rag impregnated with the stuff is all that's needed - a smear goes a long way. It's also an impressive penetrating oil.

Thread: Moore and Wright Value Series
23/07/2016 13:01:04

Does M&W manufacture in UK these days? I thought their clocks and electronics had been oriental for years, but don't know for sure.

I recently got a new, genuine Starrett 8" digital calliper, unseen. Brand loyalty, you see. The price seemed almost too good to be true. It was. Nasty oriental quality. It's accurate (so far...), but can't really be used sensitively because of the poor, gritty feel of the slide. So much for brand loyalty.

Re battery life. Note that SR44 (=357) cells are silver oxide, with about twice the energy density of LR44 lithium cells, and need not cost significantly more. Some sellers don't know the difference and think you're being awkward if you refuse a lithium cell. The button cells supplied with new devices from the darker corners of the orient are often junk.

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