A strange fluid

[John Stevenson 1Participant @johnstevenson1]

Personally I read the article, understood the text, never noticed the mistake and got on with life.

Is there a problem with that ?

 

John S.

[Steve GarnettParticipant @stevegarnett62550]

Posted by John Stevenson on 18/09/2010 13:35:32:

Is there a problem with that ?

 

 

No of course there isn’t – but there again, there isn’t really a problem with people admitting that they made an honest mistake, either… or is there?

 

[John Stevenson 1Participant @johnstevenson1]

Well he don’t have to admit it to me because I didn’t even read it, my mind took in what was meant as opposed to what was typed.

 

We run the homeworkshop adverts site http://www.homeworkshop.org.uk/ and we have regular posters on there who are either very dyslectic [ who thought that word up for a dyslectic ? I have trouble spelling it !! ] or not well educated, we often edit a post just to give better meaning or spelling.

We could just as well make fun of them or just not post the advert, life’s real, for now and too busy to nit pick.

 

John S.

[Sub MandrelParticipant @submandrel]

Dyslectics of the World Untie!

 

And you should all be aware that Dia Lectric is a Welsh sparkie.

 

Neil

[John Stevenson 1Participant @johnstevenson1]

Works for Dia Hatsu ?

 

OK i’ll get me coat…………..

 

 

 

 

John S.

[Steve GarnettParticipant @stevegarnett62550]

Posted by John Stevenson on 18/09/2010 14:21:05:

We could just as well make fun of them or just not post the advert, life’s real, for now and too busy to nit pick.

 

 I agree entirely – which is why it wasn’t me that started this thread. There are far more annoying things that people do in posts than miss-spell, or in this case misplace, the odd word – like making entire posts in capital letters, for instance, which really does make them harder to read.

 

If it doesn’t materially alter the meaning of a sentence in a way that’s seriously unclear, then what the heck; it can stand. That isn’t what’s annoying me here… as you’ve probably gathered.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Kwil, I didn’t use spellchecker in my postings, but maybe I should have. It should have read everyone, not everone. Point taken.

Regards Nick

[Eric LougheedParticipant @ericlougheed54619]

Who’d be an editor!

Apply the Sherlock Holmes principle and settle for one word in EDM and the other for hot air ballooning.

Eric Lougheed 

[Axel BentellParticipant @axelbentell]

Cheap fun here… I have complete sympathy for the Editor, I make spelling and all kinds of mistakes ALL the time!

[Sub MandrelParticipant @submandrel]

At least wasn’t a dianetic fluid. That would be DEEPLY strange.

 

Neil

[Jeff DaymanParticipant @jeffdayman43397]

I finally received the MEW issue where this EDM article by Mr.Walker was published. Reviewing it, comparing it to the EDM machine I built to the Ben Fleming design, and industrial machines I have used, I offer the following comments for anyone thinking of building one.

 

1. The Fleming machine and all industrial sinker EDM’s do not use electrode vibration as part of the process. Some ‘tap disintegrators” and EDM “drills” do, however. In my Fleming machine it works totally fine and fairly quickly without vibration. Building a unit without vibration equipment will save a lot of time and effort.

 

2. The Walker machine uses a stepper motor servo to move the electrode. That is fine, and is used on many industrial EDM’s, but the Fleming design uses a DC gearhead motor and leadscrew. This is far less complicated to build a control for, and very inexpensive.

 

3. The electrode mechanical support and bearing in the Walker design is very complex and looks hard to make. The Fleming design uses a really poor design for this component also. There is a much easier way to achieve great results simply- if anyone wants to build an EDM please send a private message and I’ll elaborate.

 

4. Special paper wound capacitors are called out. These are not necessary for making an EDM that works. The ones I used are commercial ones exactly as specified in Ben Fleming’s design and were available at an electronics supply firm at very little expense.

 

5. Several components are not labeled on the circuit diagram and unconventional symbols are used in several places to note where a connection is made that would be inconvenient to draw on the diagram. Not good practice, could lead to big errors and much smoke.

 

JD

[Billy MillsParticipant @billymills]

 I would very much agree with Jeff. The article describes a one-off design that is somewhat old. Paper dielectric capacitors are a very strange choice, they have not been made in any numbers for many decades and are obsolete devices. The basic design is obviously a test bed to explore various concepts- such as vibration. However the basic mode of operation -RC relaxation- is not an optimal choice.

 

The use of vibration is interesting, the advantage is that if the mechanics are very rough  vibrating one electrode results in some sparking even though the gap may be way out of a sensible distance however it does mean that most of the time the gap is wrong , the discharge rate is 10%-1% of what it should be and the surface finish is much rougher that it could be. That suggests that the positioner had excessive backlash, vibration was used  in an attempt to overcome too coarse stepping or backlash.

 

We must await the rest of the series however it is very disturbing to read that the writer requests help with a resistor value- such issues should be sorted before publication. It would have been very interesting to see details of the much more modern design that was at the last MEX.

Regards,

Alan.

[David Clark 13Participant @davidclark13]

Hi There

The author did not ask for the resistor size.

The editor did as it could not be read from the original.

The original circuit designer was the authors father and is no longer with us.

 

regards David

 

[DMBParticipant @dmb]

Hi David Clark 1,

Re your posting on 18/9/10 under “a strange fluid” thread, regarding adverts over text and you said “might be your browser”. I am also suffering this prob. on this thread, using IE, so I thought I would try Firefox and sure enough, prob. red!!

Well I never! Good `ol Microsoft.

John

[Axel BentellParticipant @axelbentell]

Posted by John Coleman 1 on 08/10/2010 09:47:52:

Hi David Clark 1,

Re your posting on 18/9/10 under “a strange fluid” thread, regarding adverts over text and you said “might be your browser”. I am also suffering this prob. on this thread, using IE, so I thought I would try Firefox and sure enough, prob. red!!

Well I never! Good `ol Microsoft.

John

 

 

 I´ve had this prob too this morning! But not atm. Try to log in anew, or even reboot!?

[David Clark 13Participant @davidclark13]

Hi There

If you get a funny thread, let me know.

I may be able to correct it.

If I don’t know, I can’t do anything about it.

regards david

[Howard JonesParticipant @howardjones35282]

god no!

the model engineer postbag will be filled with letters of woe.

 

I’d build the spark eroder if only there wasnt a typo…..

wail, gnash, weep. if only there wasnt a tyop…..

 

hey guys. see the big picture not the bloody punctuation in life.

 

in attonement you all owe the editor a decent interesting article on how you use the spark eroder.

 

btw one of our local expert spark eroder users swears by the orange citronella fluid for his dielectric. keeps the mozzies away too he says.

[Billy MillsParticipant @billymills]

I would agree with Howard that the aggro over one misspelt word is a lot of effort over very little. EDM is however an important topic in that:-

You can build a useful machine at home with little outlay.

You can machine fully hardened metals as easily as soft metals

You can cut  splines or rectangles or any other complex shape.

The  EDM process is potentially very precise.

There are still lots of facets of EDM to be explored.

 

There are several published designs that are straightforward and work  well. But there are some issues with the Walter design. Firstly anyone trying to duplicate the design  would find that:-

  1) paper capacitors are obsolete ( for about 40 years)

2) The SAA1027 is a 1970’s part also obsolete

3) 48 step 12V motors are virtually obsolete, 200 step lower voltage parts are the norm.

4) there are no mains fuses at all.

5)The ammeter shunt is a hopeless case.

6)The vibrator is ill conceived to say the least

7) The complete lack of EMC filtering is a disaster for those living near.

8) The limit comparitors and bistable are confused and overdone, you only need half the parts to get the same results.

 

It is conventional to use standard symbols for circuit diagrams and to include component values on the diagram so that the diagram can be read- just   “R1” stops us understanding the mind of the designer.

It is completly understandable that stuff happens when you have 3 mags to edit each month. Equally “mechatronics” – the fusion of electronics and mechanics- is increasingly important and interesting. So we want more interesting articles of all kinds- some of which will have some electronics content.  So I would sugggest to David that it would be good to have specialist project parts reviewed by a reader or two who could assist in shaping an article for publication.  I offer to do that.

Regards

Alan.

 

[Axel BentellParticipant @axelbentell]

Posted by Alan Gray 1 on 08/10/2010 18:04:46:

…Equally “mechatronics” – the fusion of electronics and mechanics- is increasingly important and interesting. So we want more interesting articles of all kinds- some of which will have some electronics content.  So I would sugggest to David that it would be good to have specialist project parts reviewed by a reader or two who could assist in shaping an article for publication.  I offer to do that.

Regards

Alan.

 

 I agree totally, “more mechatronics”! ME/MEW feels a bit stale to me at times, still I like both though! I belive more young people would like a more modern flavour (like Model Mechanics was) instead of half a mag full of old fellas riding steam locos. And I add that I like steam (and old people), just so no one feels offended.

[David Clark 13Participant @davidclark13]

Hi There

Someone is redesigning the circuit using more up to date components and this will be published after the current series is complete.

regards David

[Howard JonesParticipant @howardjones35282]

alan has hit the very core of the problem I’ve faced.

I have had a go at a few the spark eroder circuits and every time I encounter a chip or chips in the circuit that are utterly unobtainable.

what is equally frustrating is that the manufacturers seem to lock the technical info regarding their circuits away so that it becomes near on impossible to locate a suitable workaround to a circuit. now I have electronically savvy friends who say that the problem is trivial and easily worked around but I notice that not one of them has built an eroder despite being well versed in what they are capable of.

so I suspect that the circuit design isnt actually that trivial

my friend the rocket scientist model engineer built amesbury’s circuit and used it successfully for 3 years but I notice in his notes that after that period he gradually had to replace every component on the boards. I suspect that amesbury’s circuit overloaded the components or drove them at their limits to achieve the result he obtained.

we in model engineering really do need buildable spark eroder circuits.

what can be achieved with a spark eroder and some talent is truely remarkable.

 

btw my friend the rocket scientist solved his problem by buying a $25,000 commercial spark eroder and the work he has done on it is absolutely stunning.

 

my pockets are somewhat shallower and I am really hanging out for a spark eroder circuit I can build.

 

alan you could really do model engineering a service by designing a buildable circuit that didnt over drive the components.

[Howard JonesParticipant @howardjones35282]

alans comment “edm can be very precise”

 

a friend who just recently passed away showed me a job he had done for a customer.

it was a paper punch just on a meter in length. it had a platten with a little keyhole shaped aperture about every 5mm. mating with this was the punch which had raised tapered keyholes to punch through the paper

to get the punch to function accurately at all the dimensional tolerance was a tenth of a thou (sandth of an inch) over the metre distance.

the job was done with a wire eroder.

 

utterly utterly stunning work.

[Jeff DaymanParticipant @jeffdayman43397]

Posted by Howard Jones on 10/10/2010 03:02:16:

 

 

“my pockets are somewhat shallower and I am really hanging out for a spark eroder circuit I can build.

 

alan you could really do model engineering a service by designing a buildable circuit that didnt over drive the components. “

 

 Howard, you can build a working EDM simply. If I can, you can, and I did. The Ben Fleming circuit does work and you can get all the components from commercial electronics houses like RS. The EDM How-To-Book is available from Camden Miniature Steam Service in the UK for roughly 20 UK pounds. The circuit is designed for 120VAC but you would  only need to substitute 240 VAC to 48 VAC transformers and it should work fine.

I did have one problem with one IC that overloaded repeatedly, but I solved this by bypassing the IC with a substituted circuit with heavy duty components. There is a Yahoo dot com forum for the Fleming machine, and when I reported this trouble several people said they had the same issue but many said they didn’t. I would say there may be a tolerance problem with the IC itself, and it is operating too close to its limits. Some people may have a problem and others won’t. The substitute circuit has heavy duty components but does the same job as the original IC. I put this circuit up on the Yahoo dot com forum for the Fleming EDM. It was very inexpensive to build. I’d be glad to share a copy of the substitute circuit with you. I can’t share the Fleming EDM circuit diagram however, as it is copyrighted in Ben’s book.

 

The Fleming machine is a simple workable EDM.

 

[Howard JonesParticipant @howardjones35282]

I have seen the title of the book in their cattledog but wasnt aware that it had a buildable design in it.

I thought it was book on techniques.

I will hunt out a copy. thanks.

[VersabossParticipant @versaboss]

To all those mentioning ‘the Fleming machine’:

Do you mean the contraption described in the booklet ‘Ramah Machines Metal Disintegrator’?

A combination of a vibrating engraver and a welder 

Greetings, Hansrudolf

[Author]

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