Member postings for Martin Dowing

OK,

link below:

https://www.ebay.com/itm/22pcs-Keyway-Broach-Collared-Bushing-Shim-Set-Kit-Metric-System-For-CNC-Router/191769640179?epid=17003842846&hash=item2ca65c7cf3:gXd0AAOSw-itXwFap

Martin

Edit: now link should work

Edited By Martin Dowing on 08/12/2017 20:54:35

Edited By Martin Dowing on 08/12/2017 20:56:48

I want to buy a broaching set.

Have found one which is described as broaching set for CNC router.

I do not have CNC router but I do have 3t arbor press.

Is it going to work with this broaching set or is there some peculiarity involved which I do not understand and yet which makes it impossible to use my press?

Asking because I do not want to throw away my money.

Martin

I am planning to correct MK2 socket on my ML7. It is one of last jobs to be done on my old otherwise accurate lathe. To this end taper turning attachement will be deployed. Jig for holding a bigger version of Dremmel, designed to be mounted in the lathe, is now under construction. It will have dovetail slide tangentially set, so very accurate adjustments can be made. Phosphor bronze bearings which are actually not a bad fit as they are now will be professionally scraped in (I am not up to the task yet), headstock allignement will be made as close to perfect as possible (this is now not a problem for me, can do it and well) and then socket will be corrected with few tenths cut.

I will even possibly make 2 or 3 spare spindles from suitable material, all in perfect allignement, socket ground in the machine and nitrogen harden them. Recently I am studying research papers treating about cyanate bath for nitriding. These work in lower temperatures (450*C) than cyanide bath does (600-700*C) and are also substantially less toxic.

Martin

Many thanks for your comments.

All of them helped to understand the problem. My material is a bar.

Smelter peoples have said that they are making such bars from excess of smelt as occassionally they sell and if not, they can always be remelted. It is not a sash piece. Had few and they were actually OK.

I have managed to turn it after all. Once diameter have gone from 42 to 38 mm no more troubles was encountered. Ordinary carbide insert was good enough to chew by hard part. HSS stood no chance. I have few CBN inserts for hard materials but in this case it would be wasteful to deploy them.

Regarding heat treatment - I have large fireplace so with enough of wood it might do the trick. Good to know for the future. What are you using to prevent scaling while heating metal to red heat?

Martin

Life is more diffcult than it initially looks.

You will need to regrind of all mating surfaces as well, eg saddle and tailstock, corresponding gib strips etc.

This can be done in Mytholmroyd (where whatever is left out of Myford is located) but if you are located in Poland as your surname suggests, your option is to find a fitter who may undertake rescrapping it for a reasonable money.

Have you managed to get bedways and mating surfaces rescrapped, your machine will be superior to any ground product, possibly better than new.

IMO doing any scraping job on surface under headstock is of no use, but if you go for grinding, by all means do it as well. You will possibly need to reallign headstock with bedways after all this job. There is a lot of mythology around about supposed difficulties in doing so. Contrary to all of that I have found this task quite straightforward. You will get there with set of shimming strips, precision level, test turning bar with 2 bobbins 6 inch or so apart, patient measurments and 1-3 days of dedication. Later you may need to reallign crosslide.

I was there in the past. Still tapered socket needs correction and suitable grinding jig to be mounted on crosslide is under construction.

Martin

@XD

0.008 inch, eg.8 thou?

Martin

Got a bar of grey cast iron, absolute pig to machine.

HSS tool got simply deformed upon attempt to turn it and now need general regrind and carbide tool barely cope with it leaving surface which looks somehow "tortured".

How deep such a layer might be?

Should I consider this bar faulty and throw it away or after chewing through first 2-3 mm there will be some "normal" iron?

Martin

ACME and 30deg trapezoidal threads are much easier to manufacture than square version and I have red that this is main reason why they are used. Sqare threads are not difficult to engage if little backlash is permitted and they are not tending to partially disengage during heavier cuts, what leeds to thread errors.

IMO suare version is superior.

60 deg threads are even worse in this respect and they are also mechanically unsound. OK, hardened versions might be OK for some applications.

Martin

Edited By Martin Dowing on 04/12/2017 08:25:22

"it is reproduced from literature"

Not really. Link specified by you is claiming explicitly "H315.(11.43%) causes skin irritation", *You* are claiming 93.75% contrary to link which you have submitted yourself. So perhaps read it again.

"R(risk) and S(safety) phrases are assigned to chemicals by concensus in an expert committee of the EU"

There are plenty of commities in the EU, unfortunately most of them entirely useless.

"As a past member of the HSE's Advisory Committee on Toxic Substances, I assure you the TUC, CBI and HSE members think otherwise."

Who cares what they think? Industry is moving production to China and elsewhere and they have nothing to say there. Bureaucrats you mention are one of many causes of pending economic ruin of West where everything is outsourced and only bankrupt banksters and hopelessly indebted public is left.

Martin

@ Silly Old Duffer

Reaction of citric acid with rust is discussed here:

"Chemistry and metallurgy" Second Revised and Enlarged Edition; A. Sherry; J. S. Beck; A. E. Cruddace; page 357;

It reads:

"Fe2O3 + 2 H3Citrate ----> 2 FeCitrate + 3 H2O

where citric acid is represented by H3Citrate to simplyfy formula."

Martin

@Fowlers Fury

Quote from your link regarding Copper citrate:

"H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]
H315 (11.43%): Causes skin irritation [Warning Skin corrosion/irritation]
H400 (77.14%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]
H410 (74.29%): Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]"

I cannot find here at all that it is causing serious eye damage and only 11.43% of reports (not 93.75% as you claim) are recording skin irritation.

My own impression about copper citrate is that it is relatively harmless compound, unless consumed deliberately in considerable quantities and will cause skin irritation and sometimes allergy in rather few particularly careless or sensitive individuals, though I would avoid breathing in dust of it.

Statements about toxicity to aquatic life are correct albeit I would call it "toxic", not "very toxic" because if it is "very toxic" then other common industrial chemicals like cyanides would be "very very very toxic". You could not call them "extremely toxic" either because if you do, then alcaloid pilocarpine would be "extremely extremely toxic" etc.

From my own long industrial experience as research chemist I have found that most of risks assesments are rather political/legal documents of very limited value in real life. Their production is a great time wasting exercise and it is sometimes actually endangering health of workers because they are first forced to produce this nonsense to satisfy legal requirements and then they still must complete planned tasks, often in hurry and therefore without proper attention, because much time already was wasted on writting risk assessments, getting them authorised etc.

Re: descaling of copper from copper oxide: I would use 10-20% hydrochloric acid but on copper, not on brass. You can remove copper oxide from copper or brass with disodium salt of EDTA (di-sodium ethylenediamiotetraacetate or di-sodium wersenate) at pH 7-8, eg essentially neutral conditions.

You can easily buy this reagent over Internet. It is used for lead battery reconditioning and many other things and rather cheap. It will not remove copper sulfide scale only copper oxide.

Martin

@Tim Stevens,

Waste sulfuric acid containing Fe^2+, Fe^3+, Cu^2+ and Zn^2+ is to be treated with limestone or lime to neutralize acid, then excess of limestone will produce zinc and copper carbonate (inoluble) together with also insoluble basic carbonates of iron and copper and hydrated oxides of iron. Bulk of solid is calcium sulphate (gypsum). All of these compounds are also ores of respective elements, so they are not unknown to Nature.

this cake goes to landfill.

Martin

Hi Maurice,

Potatos contain small amount of oxalic acid, which is known to dissolve rust.

It goes like this:

FeO(OH) + 3 HC2O4^- -----> Fe(C2O4)^3- + 2H2O

So insoluble rust, FeO(OH), is reacting with 3 hydrogen oxalate anions and soluble trioxalatoferrate(III) is formed.

Martin

@Fowlers Fury,

Sorry for slightly unpolite comments but equations you are writting as reaction of citric acid with Iron oxide is an utter nonsense.

Fe2C3 does not exist and even if very recently something of such composition was produced, that would be done by some meddling with elements above 900*C or so. It *certainly* cannot be made in water solution from iron salts or oxides and citric acid even if someone have written such nonsense on the internet.

Existing Iron carbide has a formula Fe3C, it is known as cementite and is produced by rapid cooling of solution of carbon in iron. It is responsible for difficult machinability of *chilled cast iron*.

Reaction #1 in your second post is also messed up, that because Fe(OH)2 does not dissociate and its solubility in water is very low.

Correct statement would be:

2Fe + 2H2O +O2 ---> 2Fe(OH)2

I doubt that CO is formed easily from citric acid and iron salts or oxides/hydroxides in water solution during pickling

I suspect that *smelting* citric acid with rust at temperatures of 130*C and more may produce some carbon monooxide.

It is known that carbon monoxide is formed by slight heating citric and conc sulfuric acid or better with oleum, which acts as dehydrating agent.

Reaction goes as follows:

CH2COOH-C(OH)COOH-CH2COOH ----> CH2COOH-CO-CH2COOH + H2O + CO

On the left side of equation is citric acid and on right one something known as acetonedicarboxylic acid.

Regarding toxicity of citric and oxalic acids. They are for all practical purpose harmless compounds, lethal dose killing about half of those affected is ~ 20-30g for oxalic acid and about 40-60g for citric acid. Soluble salts have comparable toxicity. To get poisoned by these deliberate consumption of considerable quantities is needed.

One may say that oxalic acid is about 10 times more toxic than kitchen salt.

Regarding rust removal, it is monopotassium salt of oxalic acid (COOH-COOK), which does job the best. It is commercial product.

Fosforic acid is also often used for derusting and it is more pleasant to work with than hydrochloric or sulfuric acids.

Martin

"Frank Whittle did not invent the Jet Engine" Go on then, who did?

Most likely few junior engineers working together with him.

Martin

Re Moon landing deniers.

Russians were closely watching American activities and if there is some credible evidence that Moon claims were false, this would surely be flagged in communistic block but it was not. Hence it is unlikely that Americans cheated.

Some small cheat, where the Eagle could simply make an orbit or few around a Moon and come back on Earth without landing there is still technically possible, particularly in regard to first visits reported.

IMO all these landing deniers are coming from quite unconfortable situation that humans are already post peak in respect to manned space conquest, eg we are not going there anymore, not to the Moon and not anywhere else, due to lack of courage and most imprtantly lack of resources to make it happen again. Basicly reasoning is that if now, after so much progress we are not going there, then initiat claims are surely a lie. Technologically inferior society cannot achieve something what more advanced one cannot. This reasoning is false but nevertheless convincing for many.

So regardless, what the truth is, as long as the venture is not repeated again, school books (or their electronic version) 200 or 300 years from now on will treat Moon landing claims as great myth of XX century, of course provided that peoples 200 or 300 years into the future will still be able to read and write. Our education system is doing all it can to make sure that it will not be the case.

Martin

Debris on low orbit gradually decay due to traces of atmosphere present there. within few decades they would fall into air and burn.

Debris on geostationary orbit would not suffer this fate due to a lack of appreciable quantities of gases causing orbit decay.

If they are of small size (say 1 mm) and released in quantities of many millions, no conceivable technology exist to clear them out (or even to track them) and natural orbit decay could take many millenias.

So such debris are permanent for all practical purposes.

Martin

Edit:

I remember statements that blobs of plasma sufficient to damage satelites are formed when weight of debris is in range of 10-100mg. This would comfortably fit into tungsten ball diameter of 1-2 mm, hence edit of my initial post.

Edited By Martin Dowing on 01/12/2017 10:29:31

Have red sometime ago about planned weaponry meant to vandalize space with millions and millions of 1-2mm diameter tungsten balls. Few cargos would be good enough to render low orbits useless for decades for *any* craft, including all military surveilance. Similar vandalism of geostationary orbit would be for all practical purpose permanent.

Martin

Edited By Martin Dowing on 01/12/2017 09:14:05

About 15 years ago I have purchased few micrometers of Mitutoyo on ebay but it was good old time when cheats was rare. At the time such items were going for 20 queeds or so. Bought few with ranges 25-150mm, hardly used, with certificates.

At the time I have also bought ex store 25mm and 1inch Starret external mic, bore allignement clock (0.0005" ex Verdict and precision clock ex Starret. All with vernier scale reading, mics are up to 1micron accurate but such accuracy is rarely needed and in any case requires great care to reproduce readings. These are expensive items. 15 years ago each such piece was approx 120 queeds and I had permanent 20% discount negotiated. Of course together with mics they are providing calibration bars of accurate lenght.

Perhaps my best buy of precision equipment on ebay was Watson precision level made in 1960-ties. My friend from academia (experimental physics) looks on that one with envy. Advice is to keep it as piece of historic equipment but in his opinion only laser interferometers can compete with it. Between bubble levels it is a jewel and it was only 15 qeeds on ebay.

Martin

Edited By Martin Dowing on 26/11/2017 10:22:19

Americans already need someone to keep them safe from their police forces and other agencies (which can be even more dangerous and abusive than the police). They also need someone to keep them safe from corrupt courts and lawyers.

Sadly, no such an entity exist.

They also need armed forces to turn some most retarded countries into an utter ruin and prompt millions of desperados to move to Europe and also to America and from time to time blow themselves up between unsuspecting members of public. I bet, they would be much safer having next to none of such armed forces at all. Maybe few thousands of personell manning few dosens of nuke launchers and supportive infrastructure would be enough. No external actor would dare to meddle.

The same coming here soon? Hmmm......

Martin