Member postings for Kiwi Bloke

Thanks everyone for helpful tips and good ideas. I think non-tapered gib strips are a triumph of practicality over theory. Perhaps that could be said of a lot of engineering. The many detail design variants suggests that the search for the perfect solution continues... I hope discussion on this thread helps anyone who is struggling with the wretched things.

To add a little detail about my 'problem' machine. It's a well-respected, very small lathe, manufactured far from the orient. I won't identify the maker because I don't wish any implied criticism to tarnish their reputation. The machine is unworn and crud-free. I can't access it at present, but, from memory, the vertical height of the top-slide gib strip is in the order of 5mm, and the adjusting screws are M3, so we're dealing with awkwardly small stuff.

Thinking theoretically about gib strip location, stability, etc. makes me wonder the things ever work acceptably. It seems wrong for adjustment screw forces to act slantwise (at an angle to the surface of the strip), rather than normal to the strip. If the screw bears into a dimple, the force on the gib will be deflected 'down the slope' as the screw is tightened, won't it?. A ball-ended screw, or an interposed ball, bearing on the slanting, plane back surface of the gib should apply (and react) force along the sphere's radius, at the point of contact, and hence normal to the gib. Isn't this what we want? Are dimples a bad idea? Perhaps I'm confused - which way is the strip pushed when it reacts sideways slideway forces - 'uphill'? The more I think about this, the confuseder I get...

It seems to me that the gib will tend to be deflected (or simply just fall) 'down the slope', so should its lower edge be arranged to bear 'properly' on the moving slide? In other words, should it be properly finished as a bearing surface?

The parallel gibs on cross-slide and top-slide on one of my lathes are particularly difficult to adjust properly, and produce inconsistent results. I'm planning to check, scrape and dowel the strips (GHT-like) and to attend to the adjustment screw seatings on the strips, but I'm not sure what's the best solution.

The gib strips are located at present by a single dimple, mating with the end of the adjustment grub screw. It's the usual problem of an inadequately-located gib strip, moving relative to the screw. The other screws bear on the plane face of the strip.

An additional problem is that the screw responsible for one slide's adjustment causes the gib strip to bind against the 'roof' of its female dovetail. One might expect the screw to 'push' the strip 'down' the face of the dovetail, but, clearly, the strip's dimple and the end of the screw bind, pushing the strip 'up' the slope.

I've read previous threads on gib strips, but still would like to ask questions.

I assume that the long sides/edges of gib strips should never be forced into firm (and therefore friction-ful) contact with the dovetail 'roof'. Ideally the gib strip should contact only its adjustment screws, dowel, if present, and moving face of dovetail. Correct?

Ball-ended screws, or balls between screw and strip, bearing on the plane surface of the strip, have been advocated, but is this sensible, since it offers no gib strip location or restraint? Would dimples help? If so, what shape?

Dog-point screws bearing in larger-diameter square-ended 'pockets' - if the strip is thick enough for this?

One central dowel, or two, each towards either end?

I've seen surface grinder slides in which the gib strip adjustment screws bear perpendicularly on the face of the strip. This seems a better idea than the customary oblique bearing. Might one consider conical-point screws, such that there is (hopefully) line contact between gib strip and the side of the cone?

Other/better ideas? Yes, I know, taper gibs...

Why bother trying to get your superior OS to try to talk with Windoze? You could bring your laptop back to useful life by installing Linux on it, so that it becomes a dual-boot device (or, of course dump Windoze altogether). The installed Linux should be able to mount the existing Windoze partition(s). Then you have the simpler task of getting two linux boxes to talk to each other, and two computers running a superior OS!

ME used to have staff writers who knew their stuff. Now it seems that it has to rely on submissions from the public. Not all members of the public are authorities... Just trying to ensure that submissions are sensible and correct must place what I would think is a barely tolerable burden on the editor(s). Occasionally the burden seems too much. Dare I add to the burden by requesting better proof-reading?

The general public seems to accept dumbing-down. Modern journalism too often values entertainment over information. The horrible neologism 'infotainment' has been coined in recognition of this phenomenon. It's dammned hard to write well-informed copy, but easy to waffle on about your own opinions. The 'hi-fi' and popular automobile journals are prime examples. So, if business is all about making money - and the product be damned - and the sheeple are happy to pay, we get where we are.

Sorry - last remark meant in general, not to insult ME or MEW.

Edited By Kiwi Bloke 1 on 14/08/2018 11:33:13

Edited By Kiwi Bloke 1 on 14/08/2018 11:35:54

Decades ago, Asbo 2000 drill bits were advertised with photos of them through files. No idea if they are still available. Seen demonstrated, producing bright red swarf. Sandvik, and others, make bits designed to drill down broken-off taps. They are pyramid-ended, as Colin Hawes describes. For all I know they are stellite. They are not cheap. Orange swarf and sparks!

Hopper - Absolutely! Some plastics are the wonder, neverlasting material industry's salesforce has been looking for. I've had many plastic components deteriorate or even disintegrate within a couple of decades of purchase. I usually replace seals after any dismantling that will have disturbed their relationship to the shaft, etc. The new bearings went in with the original seal because I couldn't immediately find a replacement that I thought I had in stock*.

Howard - I agree about the seal. What surprised me is that I really don't think the seal wore out 'normally', but that the main problem was that it deformed during 30 years of minimal activity. Perhaps it stuck to the shaft and its surface ripped at each infrequent start. Of course, once it was in a configuration where lubricant was squeezed out, it wore quickly - and noisily.

Muzzer - had I been able to get bearings with non-contact seals, I would have fitted them, if only for better lubricant retention. Some conventional bearing seals exert much more drag than others, but you can't test them in sealed packets very easily, so I stuck with the single, external, easily replaced seal. The poor little motor is rated at only 1/8hp.

* It eventually turned up, of course, exactly where it should have been.

Tasteful in moderation, vulgar in excess. The Americans just love it!

Thanks everyone for your suggestions.

Bearing in mind (apologies...) the age of the bearings, it seemed a good idea to replace them, so in went a pair of Polish NSK 6201ZZCM. The 'M' clearance rating is supposedly tighter than the C3 rating commonly available here, and is considered good for motors - quiet-running. Chinese bearings avoided - some must be fine, but which?

Motor reassembled with well-greased seal. Silence - for 30 seconds, then Squeeeek. Not the bearings then... With a hook probe, I was able to flick the seal's spring off whilst the motor was running - silence! The seal is a muck-keeper-outer, not an oil-keeper-inner, so the spring is accessible on the outside. So Mark is right - it was the seal! The removed bearings spin 'nicely', but with less grease drag than one would expect, so it was a good idea to replace them.

Inspection of the seal with a magnifier revealed that there was a matt cylindrical land, about 1.5mm axial length, in place of the expected sharp lip. The shaft was unmarked. This isn't a seal failure due to wearing-out, because of such little running time, but presumably due to the spring pressure over 30 years having caused the rubber to deform. Perhaps also long periods of disuse allowed the seal to adhere to the shaft, so that its surface was torn off at the next start.

I've not come across this before, but perhaps it's a well-known failure mechanism. Anyway, the thread is now here for anyone who searches for a solution to a squeaky motor.

What about in a location prone to earthquakes (I'm not far from Christchurch, New Zealand)? Do we bolt machines down and risk damage as they rip the rag-bolts out of the concrete, or hope the machine walks around on resilient rubber pads, but doesn't fall over? I fear the Kiwi way is to ignore the problem - "She'll be right, mate".

John, I'm fine with pedantry. Of course, you're right. Please excuse my terminological inexactitude - it's getting late here on the opposite side of the world. Now that we've got its name sorted out, any idea why it squeals?

Well, I can't fault Neil for closing a thread after mention of the Austin Allegro. After that, we all need a lift, don't we?

Let's start a new thread celebrating (what's left of) British manufacturing. It's easy to fall into a geriatric mindset where nothing is as good as it used to be - and it probably isn't, a lot of the time - but we need to protect ourselves from establishing purely curmudgeonly attitudes, don't we?

Try living on the opposite side of the world NZ), where a quality precision manufacturing industry never got established. There's a generalized sad indifference to quality, and purchases are decided by price. Orientally-produced manufactured goods, of wildly-variable quality, have a virtual monopoly, with little available from countries with long-established engineering heritage. What is available costs, in real terms, at least twice the price in Europe or USA. Try NZ$600 (that's about 300 quid) for a Henry vacuum cleaner! Nothing Swiss in the engineering supply houses, but plenty of low-quality rubbish I don't want. Materials are a problem too - 6061 and (IIRC) 7075 alloys are all that are readily available - at a price.

So, cheer up! You've still got quality innovators and manufacturers, if only you are prepared to recognise them. You can still buy quality goods and materials.

I'll start the ball rolling by mentioning a tiny few, picked at random:

Brooks saddles, Morgan motorcars, Cowells machine tools, Purdey guns, Raspberry Pi, most of the Formula 1 motor racing circus and its suppliers ...

Let's hear of more, and of firms who provide quality service, before they're forgotten.

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?

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).

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.?]

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.

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!

Apologies if this has been asked before.

Why isn't this a HTTPS site?

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!

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...

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!