Member postings for Kiwi Bloke

Steve, as you say, you need to pick the appropriate bits from Connelly. However, the basics apply pretty much universally. If you haven't heard this already, I'd strongly advise you to get a carbide, replaceable-blade scraper (or two), eg by Sandvik. The inserts are easy to sharpen, but seem to form micro-chips on their edges, quite readily, so a fine grit diamond plate is necessary. The ones with 'holes' in the diamond surface seem to cause chipping (at least for me...).

Good luck with your scraping. It's slow and physically fairly hard work. If you want to finish the job with pretty crescents, look on YouTube - Connelly's description doesn't make any sense. There are several ways to produce crescents. (Incidentally, the Americans call this pattern 'Moore pattern ', because Moore jig-borers sport it. Another case of the Americans stealing others' thunder, methinks. Crescents were around long before Moore started making machines.)

One point that Connelly doesn't make (IIRC) is that, if you're going to try to gouge out oil-retention 'pockets' (ie a deeply-scraped pattern), it's considered best to restrict these to the slideway faces that face downwards, otherwise abrasive crud collects in them.

As my hands become more arthritic and reluctant to do this sort of work, I can see myself buying a power scraper, should I recondition any more machines. Hang the expense! It'll get the job done, painlessly.

Hopper. You're right, trans-global distances make location approximations on the opposite side of the globe OK. However, The Surface Flatness Co. was in Dukinfield, which is near Manchester, if anyone's interested, and was a really useful outfit, with helpful guys. I think it was swallowed up by successive, multi-national businesses and is no more. No doubt the accountants are happy...

Well, it's a bit nasty, but if the belt's run is long enough, and there's enough room for an idler to replace the motor's pulley (in a similar position), arrange for the belt to be driven from the middle of a long run, with the motor's axis at 90 degrees to the plane of the belt. To do this, the belt has to be twisted 90 degrees. Twist it one way, and drive it from the appropriate side, and it'll go one way; twist it the other way, so you can drive it from t'other side, and it will go in the opposite direction. You'd need to arrange suitable idlers to get enough belt wrap. Of course, this means arranging for the motor's axis to be rotated 90 degrees, so it's pointing at the side of the (untwisted) belt, ie at 90 degrees to the driven pulley's axis. Hope this is clear...

Otherwise, arrange idlers to provide a lot of belt wrap, and drive the belt from its 'outside', as if a flat belt.

Resorting to gears is probably not such a bad idea...

The link to Connelly's book was well found! I thought my copy was expensive, when bought perhaps 20 years ago, but it was probably only 30 quid or so, or I wouldn't have bought it. Times change...

Mark Rand's comments about V ways illustrate why reconditioning these are tricky. However, levels really come into their own on bigger machines, where measurements can't easily be referenced directly to a reference surface. If one has a surface plate comparable in size to the machine elements that have to be checked, life is much easier, although some ingenuity may be needed to make jigs, etc., to hold dial gauges, etc.. My 2 ft square surface plate (bought cheaply, second-hand) was reconditioned to 'Inspection grade', and certificated to better than 1/10th of a thou over its entire surface *. It's therefore a better reference than an affordable level, and far easier to use - apart from anything else, you don't have to worry about the floor moving as you shift position...

* This, of course, only tells you something about the high spots, and only along the lines where the plate was checked (presumably by autocollimator, in this case). However, it 'should' be pretty good. It's now well over 20 years since it was reconditioned, and it's travelled half way round the world. It's cast iron, so now is probably out of calibration (not easy to get it calibrated in NZ, south island. I must dig out my autocollimator, before I recondition another machine...). These days, granite is a better bet, but was too expensive then. The reconditioners were The Surface Flatness Co., near Manchester. I don't know whether they're still going.

Whether a screw slot should have tapered or parallel sides depends on what sort of screwdriver will be used on them - or vice-versa. Unfortunately, Murphy's law says that, however well matched, the screw will still get disfigured. The very narrow slots found on older firearms are quite a good idea: the gunsmith's turnscrew wedges quite tightly in the slot. The last thing you want is for the driver to jump out of the slot, and skid across expensive engraving...

I think that, if I were in the OP's shoes, I'd have used a button head socket cap screw. To hell with the expense!

As above...

Just to remind folks that, should one wish to avoid the problems of gaskets by using silicone 'gasket goo', it's safer to go for a 'neutral cure' type that doesn't liberate acetic acid as it cures. This evolved acid can cause unprotected nearby surfaces to rust spectacularly.

(I realise that I don't understand the chemistry involved that makes acid fumes cause steel to rust. This acid-fume-induced rusting was used by gunsmiths to colour firearm parts. Can anyone enlighten?)

Well, it all depends on exactly what you're trying to do, and how you propose to do it. I think I understand what you have in mind: the level would be one way to check that the ways were parallel to each other, along their length. However, you need to know their relationship, across their short dimensions, as well, to ensure their surfaces lie on the same plane. Using a level for this would be pretty awkward.

I don't believe that you need a level at all, to scrape the ways of a lathe, milling machine or a surface grinder, provided you have a large enough plane surface, which acts as the reference plane, against which the ways are checked, and a reference straightedge. Sometimes it's convenient to use a machined surface on the machine (say between the ways), although it may take some work to scrape that surface flat, and ensure it's correctly aligned with other appropriate surfaces (I'm thinking of a lathe saddle, for instance). It's a big subject, with many good and less-good approaches. Getting the right sequence of surfaces to be scraped is paramount.

Have you seen the book 'Machine Tool Reconditioning' by Edward F Connelly? It's a bit long in the tooth, and tediously repetitive, but covers the basics in considerable detail.

There are quite a few types of ATF around. Some modern ones are designed for 'lubricated for life' 'boxes, which are effectively hermetically sealed, because the fluids are hygroscopic. Also, the 'slipperyness' of ATF has to be carefully controlled, because of the numerous wet clutches in auto-boxes, which also, as far as I know, don't have plain bearings in them. I don't think these modern ATFs would be ideal for our machine tools, but I don't know about earlier types. Comments about detergents stand.

Thanks. It all came up lovely. My wife was pleased too.

Howard Lewis' comments are well worth taking on board, especially if you have access to sheet metal cutting and folding equipment. I'd amplify his comments by suggesting that adding mass to a machine stand is a Good Thing. Some manufacturers, finding cast stands too expensive, use concrete-filled sheet metal structures. Increases stability and damps vibration, but makes subsequent moving a bit of a challenge...

Well, if anyone's still interested... Mindful of Hopper's warning (hope you didn't suffer permanent damage), and not having any NaOH on site, I gently rubbed the bits with a bit of gentle (grey) Scotchbrite in some approx. 5% phosphoric acid solution. Job done!

In the interests of avoiding possible confusion, note that the discussion has been about hydraulic oil, not hydraulic fluid, i.e. brake fluid.

I'm talking about what is sometimes called 'white rust'. This is zinc hydroxide which forms when zinc is exposed to atmospheric moisture, before the corrosion-protective zinc oxide surface film has become established. It's a similar situation to aluminium and its oxide coat (either 'natural' or from anodizing) being protective. Sometimes 'white rust' occurs on zinc surfaces that should have had an established oxide film. I think this is more likely in aggressive environments, particularly where chlorides are about, such as near the sea.

Treatment with dilute acetic or phosphoric acid is advocated as a treatment, but I'm worried that this will strip off any remaining zinc plating. OK, re-plating is the way to go, but it ain't going to happen...

Any ideas?

SOD. I also used to warn people to avoid 3-in-1 oil, but I have been challenged by others on this forum recently. The old formulation we all hate was vegetable oil-based. Now it's apparently mineral oil, and doesn't oxidise to a gummy mess. (I'm expecting a cheque from the manufacturers...). However, I see no need to use it, because I have gallons of light hydraulic oil, which is a great general-purpose 'oil can' oil.

I believe there are EP additives that don't attack yellow metals, but it's difficult to know what you've got in a can, so your warning is appropriate.

Edited By Kiwi Bloke on 15/08/2022 22:25:24

As above... No-one has yet mentioned that detergent additives in motor oil are there to keep contaminants (including soot, etc., blown past the piston rings) in suspension so that the full-flow oil filter will then sequestrate them. Motor oil is full of other, expensive additives designed to preserve the oil and its designed performance characteristics in the horribly demanding environment of an ic engine.

Machine tools are different. They need oils which encourage contaminants to settle out and lie harmlessly in the bottom of the headstock, gearbox, etc. Anti-foaming and anti-corrosion additives are present in the hydraulic oils mostly specified for machine tool use. They are also very slippery. There is no point using anything else - which is also likely to be more expensive. On the other hand, it probably won't hurt, except...

I read somewhere that motor oils, because of the hydrophilic detergent content, absorb water, so may paradoxically increase the risk of rusting. In an ic engine, the oil gets hot enough for absorbed water to evaporate away. Engines standing idle for a long time can rust internally significantly, notwithstanding the oil inside. I once had to store an old cast iron surface plate in a very damp garage. I covered it with paper, and soaked the top with synthetic engine oil. It rusted spectacularly. Older and wiser now...

I wish to remove the surface roughness that corrosion has caused on some small, slender zinc-plated steel items. They are rather delicate and do not lend themselves to attack by abrasive devices or materials. I don't wish to damage what remains of the plating. Is there a practicable chemical method to safely remove the zinc hydroxide/oxide without significant risk to the remaining zinc and steel?

I know nothing of how different types of paint adhere to different metals. I suspect some rely mainly on mechanical keying (think Velcro), whereas others probably rely more on intermolecular forces. Perhaps someone will tell us. All the advice above is no doubt tried and tested. Mechanically stripping the surface of contaminants, whilst simultaneously roughening it, is clearly a good idea, but the surface must then be kept free from contaminants, including finger-prints. Roughening not only provides something for the paint to grab onto, but also increases the surface area, so even a weak paint-to-substrate bond is strengthened.

Getting rid of greasy contaminants is important, because they may prevent the paint from wetting the surface adequately. It isn't good enough to wipe the surface with a solvent-soaked rag. That just makes the contaminant film thinner. It is difficult to remove the last few layers of molecules. Scouring powders, elbow grease and (preferably distilled) water removes contaminants and roughens the surface in one go.

Test for wettability by dripping on some (distilled) water. It should spread out uniformly, as a very thin film. If it beads, the surface isn't clean enough. Rinse and repeat...

Wow! What a beauty! Lucky you. Better buy a lottery ticket...

I'm glad to hear that Mortons are providing good backup. Whilst folk are rightly praising the new crew, let's give a vote of gratitude to Beth and her colleagues, who speedily and amiably filled the holes in the delivery of ME and MEW that covid / lock-down / the global postal network caused. Thanks to her/them, my ME and MEW subscription is complete. I hope Beth et al weren't unceremoniously dumped on the scrap heap by the new owners.

If you have a fixed steady with a frame that can be opened, and clamped shut (Myford style), a method advocated of old is to set the fingers as described above, with a thin shim (Izal or Bronco toilet paper - probably best not to bring those unpleasant memories to the surface...) between the two clamping faces of the frame. Then remove 'shim' and tighten the frame. Grease the fingers. This allows firm finger pressure to be applied with little risk of pushing the workpiece out of true, during the setting process. Best to clock it, to check your steady behaves properly when treated like this.

Just discovered two PMs with kind offers of help. What good folk there are on this forum!