Member postings for David Littlewood

Clive,

Which particular nasty are you referring to? It is certainly standard practice to stopper bottles containing hydrochloric or nitric acids (well, usually plastic screw caps). Sulphuric acid gives off no fumes anyway.

David

Clive,

Both nitric and hydrochloric acids give off highly corrosive fumes separately (and worse when mixed). I would not keep either in a workshop, as even in stoppered bottles it is hard to avoid enough escaping to cause problems for any ferrous (and many other) metals.

Alan's suggestion was indeed ingenious, but it does have one drawback. If you are turning to a shoulder, it means the end position of the cut (as measured by the leadscrew handwheel, the bed stop, or the DRO, whichever method you use) will change at each move of the topslide. Not insuperable, you should be stopping a few thou (sorry, a hundred microns or so!) short, by eye, and then finishing the shoulder face later; it's just something else to have to think about when doing a repetitive cut.

Personally I'll stick to the 40 thou per mm until there's a gnats todger left, then by measurement. The table inside the front cover of the Zeuss booklet is good for this.

David

Edited By David Littlewood on 25/08/2012 13:31:04

Michael,

On a more serious note, you are right and, as I said, there are usually some fudges to get around it - except where it's a web URL and has to be quoted exactly - but I really think it's unacceptable if we have to stop and think when and how we need to deviate from normal English usage just to get around what is by any standards a juvenile piece of software tat.

David

Spoilsport!

David

Swarf,

It was indeed a few gallstones and some teeth that was the strongest evidence on which he was convicted; don't know where they found them though.

David

Steve,

Adding dilute sulphuric acid to cyanide salts is exactly the method they use in gas chambers to kill convicted murderers - it reacts to form HCN! Maybe it was a subtle way of finishing them off quickly.

David

Fizzy,

I'm with Hansrudolf on this; you are exaggerating quite a lot. H2SO4 will indeed destroy flesh, but it takes more than an "instant" to do it. If you get a small splash on your hand, you probably have 5-10 seconds to wash it off before you suffer more than superficial damage. I too was handling it from my early teens and through university and industry, and simple care meant I never had any problems with it. I even have a few litres in my workshop for pickling and plating purposes.

Fuming sulphuric acid (oleum) as mentioned by Michael above is a different story, as it is in effect SO3 (sulphur trioxide, a highly corrosive gas)) dissolved in concentrated sulphuric acid. That gives off fairly deadly fumes and has been know to overcome people exposed to it so they fall into the hellish stuff. It is used in the manufacture of H2SO4 for the simple reason that, although the latter is just formed by reaction of SO3 + H2O, if they just mix them together they get an unholy amount of dense corrosive vapour all around. It is, apparently, more controllable to dissolve the SO3 in H2SO4, than gradually mix that with the correct amount of water later. Fortunately you are unlikely to come across it in the wild (unless you are unfortunate enough to be around when a tanker full of it crashes - in which case just run like f**k).

If you are into dire warnings, then most people are not aware that strong solutions of caustic alkali (such as NaOH and KOH) are far more rapidly deadly to tissue than H2SO4. The latter, if splashed in the eye, will usually give you time to irrigate before it blinds you (but you do still need emergency medical attention!); the former can cause irreversible damage in a couple of seconds.

David

Speedy,

Sodium chloride becoming difficult to buy in France? Are they becoming health-obsessed or do they just not like you adding seasoning to the amount the divine chef thought was appropriate?

David

It would be interesting to have an opinion from an expert in EU law as to whether "placed on the market" has some implicit limitation transactions between business concerns. IOW, a gift between private individuals not involved in a relevant business might be outside its scope. After all, as Bob indicated, what happens when the owner dies?

This is the kind of arrant nonsense which is inevitable when vast sets of rules are produced by a legion of bureaucrats brought up in a Continental system (which seems to be based on the philosophy that no-one can do anything unless given permission to do it) is grafted onto a common-law based system which starts with the assumption that you are responsible for your own actions, but must take the consequences if you screw up.

David

David C:

I have had trouble several times with the forum softare automatically changing certain combinations of keystrokes into blasted smileys (spit). On the current thread on "Silver Solder Identification" it made it impossible to insert a link, as it interprets colon followed by p as a tongue-out smiley, thus . On other occasions certain combinations of end bracket and close quotes caused problems; you can get over the latter by putting in spaces, but URLs are either right or broken.

Please could you get your web people to remove the auto smiley insertion; anyone benighted enough to use them can presumably still insert them using the drop-down menu, but just let the rest of us get on without them gumming up our posts.

David

Edited By David Littlewood on 25/08/2012 02:18:23

Potassium ethoxide??

David

If you want to know what the law says, look at the law. In this case, unfortunately, it was written - as these things usually are - by a creature from the planet Zog masquerading as a speaker of human language. Here it is: **LINK**

 Note the critical bit (it's in the Annex on page 4, would you believe - all the previous bit is actually just background justification) is "shall not be placed on the market". Some suppliers say they have legal advice which says this means it cannot be given away. I must say that my personal view is that giving something away is the very antithesis of placing it on the market, but if you look at the earlier EU (or EC as it then was) legislation it does indeed say:

"Placing on the market: means supplying or making available, whether in return for payment or free of charge, to a third party..."

See df">http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=oj:l:2006:396:0001:0849:endf , page 55

David

Sorry, this forum software is complete pants, it's wrecked the link again! You can find the regulation by looking at the post above mine and clicking on the 2006 link at the bottom of the page.

Edited By David Littlewood on 24/08/2012 23:52:42

Neil

Your post made me laugh - but you had the wrong murderer; the acid bath man was John George Haig, hanged for serial murder. He was AFAIK actually brought up in the same village as my father, thought there was quite a few years between them and my father didn't know him except by repute. He also attended the same school my father and I did. IIRC, Crippen (was alledged to have) buried his wife under the floor of his house; there was I think a small residual doubt whether he actually murdered her.

David

Edited By David Littlewood on 24/08/2012 23:23:58

Unfortunately, the length stop cannot be fitted at the same time as a taper turning attachment. I have both, but I find the TTA is somewhat more useful unless you are into serious mass production.

David

Graham,

Very nice, but why? If it isn't hardened, is there any value in using silver steel? I think for such a job, if mild steel was not considered good enough, I would have used EN24T (817M40 in new money). Machines quite well, and is very, very strong.

David

Edited By David Littlewood on 22/08/2012 14:23:37

You could dilute it (1) and neutralise it (2).

(1) Add acid to cold water in a large tub, very slowly, stirring continuously. If it starts to get too hot, leave it for an hour or two to cool down. Wear eye protection and old clothes. Suggest you let it down in about 9-10 times its volume of water ready for step (2).

(2) Cheapest alternative for this would probably be a bag of builder's lime. It's calcium oxide, so it shouldn't froth much when added. Keep adding it - carefully - until the liquid is no longer acid (doesn't fizz when you put a bit of bicarb in it). The resulting sludge will be calcium sulphate, perfectly innocuous and probably good for the garden (but don't tell anyone I suggested it, it's probably against some daft EU law despite the fact that there are whole hills made of the stuff.) The builder's lime is mildly caustic when wet, so wear gloves, but nothing too serious, builders use it all the time.

David

Edited By David Littlewood on 22/08/2012 00:31:32

This is true, and they are not properly compatible - but I don't think anyone mentioned ES collets. John referred to ESX collets, and I believe these are compatible with ER. This page is quite helpful on the subject: **LINK**

David

Mike,

This subject was discussed extensively in this thread*:

**LINK**

In brief, you should have no trouble with 3/8" (9.5 mm) tool shanks. I find no problem with 10 mm ones, but the spare room below the holder is vanishingly small, and some people find they just can't quite get the tool low enough.

David

*This shows the benefits of choosing a useful informative title when you start a new thread!

Edited By David Littlewood on 20/08/2012 12:37:32

John,

I shudder to think what the concentricity would be like if you did it by chopping off a morse taper shank and machining a female M12 x 1.0 on the corpse - even on a larger lathe. That would completely vitiate the advantage of using collets. At least using a backplate and flanged chuck you can turn the backplate on your lathe and have a decent chnce of getting it true.

David