Time for a name change?

Malc,

We must be there then.

A crank we did at the shows at the same time we were doing the camshafts, we alternated the jobs to show a bit of interest.

Ignore the last two throws being off I got bored with 180 degree cranks, though this might be a challenge to time up ?

Funnily enough the code for this was done by hand and it was only about 10 lines long [ edit 22 ] as it's two mathematical formulae that work together, one for Y and one for Z, then repeat every pass until the journal is done.

In operation X once set doesn't move, Y goes in and out at the same time that Z moves up and down so the centre of the cutter is always over the centre of the journal. When machining, being a formulae and not a G-code it just sat on the screen and no one could understand it so at the end of the first day we ran the formulae thru Excel and got it to spit the G-code out. Following day because people could see the G-code scrolling thru they were far happier but said bet that took some coding.

This was the original code:-

#1=[30] ;BAR
#2=[15] ;PCD
#3=[10] ;PIN
#4=[18] ;Passes
#5=[0] ;A
#6=[1] ;Pass

G0 G21 G49 G40.1 G17 G64 G80 G50 G90 G98
M6 T1
M03 S4000
G43 Z10.0
G00 A0.0 Y0.0 X5
M98 P003 Q#4
A0.00
M5 M9
M30
%
O003
#5=[0]
G00 Z2.0
G00 A#5
G01 Y[[#2/2]*SIN[#5]] Z[[[#1/2]-[#2/2*COS[#5]+#3/2]]*[#6/#4]*-1]
M98 P004 Q358
#6=[#6+1]
G00 Z2.0
M99

O004
#5=[#5+1]
G01 A#5 Y[[#2/2]*SIN[#5]] Z[[[#1/2]-[#2/2*COS[#5]+#3/2]]*[#6/#4]*-1]
M99

Edited By John Stevenson on 05/01/2016 23:25:28

John,

Yes, then it's got to a time for a name change.

I knew it was only a matter of time before a string of 'G' codes appeared.

You know what I thought when I first watched the video was:

Would I ever want a crankshaft made from solid bar stock in an engine of mine?

Surely with that amount of metal removal and the complex section changes left remaining, there must be a high level of induced stresses now present? Heat treatment would surely distort? Maybe vacuum stress relieving, who knows.

Or maybe just a demonstration/promotional video.

Edited By MalcB on 05/01/2016 23:45:29

Is that between centres John and did you leave something for grinding or finish with the milling cutter ?

Emgee

Malc- my 3-1/2" gauge "Kozo Hiraoka" designed Shay has a crank shaft turned from solid.

Here is (hopefully) a link to a museum page - there is a picture of a completed crankshaft:

**LINK**

Totally FYI - John.

Malc,

It was just a demonstration but I'm curious about your remark, "would I want a solid bar stock in an engine of mine ? "

Not being an expert on model engines I thought most were like this or silver soldered up for bits ? In fact at the show it was noticable the number of folk who came up to us and remarked, "wish i'd got that, I was making a crank for my Lesser Crested Supercharged Hyphenated Gronge and the tool dug in, ripped it out the chuck and bent it all up"

One guy was on his 4th but in all fairness this was that tiny Whittle V8

Also as far as I know no-one heat treats model shop made cranks but as I say I'm no expert.

Emgee.

The blank has held in pot chucks and retained by a grub screw, you can see it better in the shot of the camshaft.

Because it was just a demo and for ease of setup both the crank and the cam shared the same pot chucks. The rotary table end was made from a MT2 blank end arbour just bored out and cross drilled for the grub screw.

The tail stock end as the same but parallel and not MT2. once the blank was fitted the tailstock was pulled to tension it and not pushed which would have put pressure on the blank as metal was removed.

Not a new idea at all, The old Victorian production wood lathes used the same idea. It was the only way they could turn the long slender stair spindles without them bowing and the operator wearing one.

We programmed the pin for 10mm diameter and once they had come off the CNC mill they were polished with scotchbrite on a manual lathe to clean them up. Hardly took any cleaning up. The finished up at about 5 thou bigger than they should.

Could have tweaked the program but TBH never even measured them until the job was done, all were within a thou of one another but we had not played with the tailstock hight or anything, as I say it was just a demo of how easy CNC made of a manual operation.

We tried to show these things instead of like many just engraving names on a bit of plastic.

[ EDIT ] Because of this we only machined throw journals and never plain main journals which would be an easy turning job.

Edited By John Stevenson on 06/01/2016 00:17:51

Mmmmmmm.....just thinking aloud how the material stability of a bar stock produced crankshaft like the one in the video would be against that of a drop forged item. Not really an area I have any experience in I am afraid.

I have however seen a few stability issues from bar stock machining on expensive duplex stainless where material has been continually moving whilst metal removal was taking place. In particular where the biggest section changes were.

Not sure if this ever happens or takes place with low or higher carbon steels, maybe others can say?

Interesting link as well John A.

ETW was confident enough to have solid crankshafts in most if not all of his IC engines? - but i don't see how that relates to whether or not you use CNC.

As for name changes - well 'the hobby' (or 'hobbies' will be called whatever the people doing it want, there's no regulatory body.

That said, my assumption was that the term Model Engineering owed its popularity to the influence of Percvival Marshall and his publication.

Google's ngram viewer suggests otherwise:

Looking at the details, though, this is from a very small sample. Most examples from the mid-19C use the expression to mean 'a good example' such as:

"Here comes Martin, the model engineer, in a lovely state," said one of the men. " Drunk again !" (1868).

That said, there is firm evidence for the term referring to making models before then.

In an 1874 book I found an ad for "The Model Engineers' Handybook", which is "A Practical Manual on the Construction of Model Steam Engines." The 1902 Seventh Edition is readily available if you google its title - there must have been quite a demand for this book!

Of course, as soon as people started selling machinery, salesmen needed models as they could hardly cart around a full-sized beam engine to show a prospective customer.

This 1851 passage by Alfred See (sic) not only shows that a model engineer made models then, but that it was both a profession and the use of advanced modern techniques rather than handywork to speed things up is not a new phenomenon:

Mr James' eminence suggests that 'model engineers' were a well-established profession by then!

In the absence of any real research, might I venture that model engineering started in this way as a specialist skill complementing the work of full size engineers. As the making of scale models spilt over into practice jobs for apprentices and then became a hobby for this working on full size machines and interested amateurs, it's natural that the name would be used.

Percival Marshall (and before him Paul Hasluck) popularised the word, no doubt. The very broad church that was The Model Engineer and Practical Electrician must have been the main influence on the definition of the hobby in the early 20th Century - focused on live steam but encompassing all aspects of the construction of small mechanisms in the home workshop.

I am sure Percival Marshall would be totally confounded by this hand-wringing about CNC. He enthusiastically embraced any new technology as it appeared and actively encouraged experimentation. I'm sure he would have seen CNC as just another box of tricks to use in the hobby, not an existential crisis.

From my own perspective, I don't see CNC as a threat to anything - it's just another example of how our hobby reflects full size practice.

Surely what matters to the future health of our hobby is encompassing as wide a range of engineering approaches, subjects, materials and skills as possible?

Neil

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Edited By Neil Wyatt on 06/01/2016 08:28:33

This chap, Doug Sleigh, says it very well:

www.nwlsme.co.uk/index.php/engineering/48-modern-methods-in-model-engineering

"To summarise there are lots of new technologies available to us as model engineers to me it's nothing to be scared about and there is no distinction between old and new methods all are valid none should be dismissed. I have a lathe from 1939 and a CNC machine from 2014 and I use both equally. As long as you enjoy your hobby there are no wrong methods."

Neil

If the OP wants to change their name that's fine by me. If they were asking how there is information on the web. Just search deed poll.

I find it hard to believe they were suggesting a forum name change so perhaps the above answers their question. If not a more precise name for this forum would probably be hobby-engineering 'cause that doesn't imply what people choose to make or the techniques they use to do it. model-engineer does imply what people choose to make and some, maybe the majority do actually do that, most of the time. This doesn't imply anything about what they choose to use.

Then there will be some people who have commercial interests in the area - it's not a hobby for them. Perish the thought but some might be model engineers and just make to sell.

John

-

There is one thing that bugs me about CAD on another forum, the ones that come up with a 3D drawings of a proposed engine design (Stirling Engine), with inference that "I'v drawn it so it works", but when it's analysed, there's no way it's going to work. My suggestion is (sometimes), have you built a proof of concept model?

The use of computer drawing on that forum is wide spread, from India, USA, Eastern Europe, and Australasia, and often by youngsters still at school.

Ian S C

On a Professional visit to a well known science based enterprise near to me it was observed by my guide that, when the "engineers" first come here from University we have to teach them "that just because they can draw it does not mean it can be made or work"

Neil Wyatt:

Excellent post on the derivation, etc of "model engineer" - thank you. I did a case-insensitive ngram search on the phrase and got rather different results from yours with the three variations separately plotted.

I took ME for many years but, after a period of reading MEW as well, opted for the latter. It's interesting to compare the slogans on the front cover, the latest being "THE GREAT MAGAZINE FOR HOBBY ENGINEERS" and the first "THE NEW, PRACTICAL HOBBY MAGAZINE".

Wasn't it James Watt, who, apprenticed to an instrument-maker, was asked to repair a model of Newcomen's steam engine, at Glasgow University? (Not checked, off the top of my head)

Regards

Geoff

Not certain which forum you are talking about but if you look at Grabcad, a lot of their stuff is just plain rubbish. I found an engine there recently that looked really exciting and probably talked well down the pub but when you looked closely you could see the turbochargers were connected up backwards. But of course it would never leave the virtual desktop anyway, so nobody would ever be disappointed.

Anybody started building a scale model of a CNC machine ?

Wasn't Barry Jordan doing something like this ?

Because if you build a scale model no one can say it's NOT model engineering.

MalcB,

Does anyone supply drop forged cranks for model engines ?

A name change why?

We could look to the Oxford English Dictionary for a reason not to..

Following the usual definitions - model train, computer model etc.

Model - an exemplary person or thing (a model of self discipline), (model student) - model engineer?

Modelling - to fashion from clay, wax etc - metals? says nothing about methods or size.

Apologies if I have missed anything similar in earlier posts, if so, I must have been spending too much time in the workshop!

A change to miniature would also be a poke in the eye to the engineers out there who don't make miniature examples of real things. Even I make full-sized tools for my workshop.

Now then, the debate about CNC - I am perfectly happy with my workshop and machines, no electronics to be seen anywhere, apart from a simple DRO on the cross-slide, a 6 inch digital caliper and a calculator in the toolbox.

I'm also perfectly happy to read (with interest) about the exploits of those who invest in CNC for whatever reason, and the ways-and-means developed by those more interested in manual methods.

My workshop (and time on here) is a pass-time for me, my hobby.

Phil

Actually in a couple of industrial research establishments I have known the place where apparatus was made, equipped with lathes, mills etc, was known as the "model shop".

Which is one reason why I'm not a model engineer - far too many vices.

Andrew

It's all engineering to my mind. Historically I think models or mockup's were made to advertise, sell or prove full size versions. Computer modelling and simulation for today's designs follows the same pattern. Whats in a name anyhow, our primary product is enjoyment.

Martin

I'm sure the opposite is true - many of the 19C references to 'Model Engineers' stress their vices