Drawing projection, first or third?

[David Clark 13Participant @davidclark13]

[David Clark 13Participant @davidclark13]

Hi There

What is the projection used most in industry in the UK?

Is it first or is it third.

Having learnt engineering in an American company in the UK we used both types of drawings, whatever was supplied.

If we did not understand the drawing, we went and found one of the same projection type that we did understand so we could compare views.

 

If we were totally stuck, out came the plasticene and a ‘sample component’ was quickly made to check the projections were correct.

regards david

 

Edited By David Clark 1 on 23/02/2010 20:14:25

[Tony Pratt 1Participant @tonypratt1]

Hi David, I work for an American aircraft interiors manufacturer and we use 3rd angle on all new projects. My son is doing an engineering design course at college and they use 1st angle almost all the time, sorry to be no help at all! I personally prefer 3rd angle but thats all it is, a personal preference. I would guess both are still widely used?

 

Tony

[Bill PudneyParticipant @billpudney37759]

Hi David,

I was a draftsman in the UK and here in Australia, from the 1960’s to the 1990’s.  At one stage I was contracting so I spent six months here and six months somewhere else, so I became fairly versatile!!.  Most companies here now use 3rd Angle, which if I remember  correctly used to be called “American Projection”, where 1st Angle used to be called “English Projection”.

If I had to make a choice I would have to plump for 3rd Angle as to me it seems more logical. 

cheers

Bill Pudney

Adelaide, Australia

[JulieParticipant @julie]

We originally used first angle, being a traditional UK company, but in about 1980 we changed the format to third for all new drawings, this IIRC was due to a strong recommendation in the BS for drawing practice – which I believe eventually became the default “standard”.

 

Since then I haven’t really taken much notice, when I have I have seen both flavours probably  fairly equally

 

Julie

 

(I don’t really get involved with shop floor stuff through work anymore)  

[JulieParticipant @julie]

Bill,

 

I also remember first being called normal and English with third being called American   

 

Julie 

[Steve GarnettParticipant @stevegarnett62550]

I don’t have BS308 here, but I do have a copy of the primer based on it intended for schools and colleges (PP7308). It doesn’t appear to be particularly biased in either direction, although it does say quite clearly that having mixed projections on one drawing is undesirable.

 

The only other thing it says on the subject is that if, exceptionally, a view cannot be shown in its correct projected position, that the direction of viewing given should be shown clearly.

But hey, it’s a student primer so you have to forgive it for stating the blindingly obvious!

[KWILParticipant @kwil]

I have always used 3rd angle projection ever since the 1950s, then in the UK electronics/defence industries.

Edited By KWIL on 23/02/2010 22:54:14

[Gone AwayParticipant @goneaway]

I live in Canada where 3rd angle projection is used exclusively (as in the US).

 

Before I came to Canada in 1968 from the UK, I learned drafting (sorry draughting) both in school and at university and in each case was taught 3rd angle in addition to 1st on the grounds that, although 1st angle was used traditionally in the UK at that time, there was an increasing trend towards the use of 3rd angle which was likely to continue. That was  40-odd years ago. I read somewhere recently that 3rd angle now predominates in the UK but I can’t recall where I saw it or how reliable the source might be.

 

Does the fact that you asked, David, tie in with the drawings published in the magazines? Given my almost exclusive use of 3rd angle over the years, I’m naturally most fluent with that but I can (and do)  handle 1st angle easily enough (I just have to remember not to get too automatic about it). What is a real problem (for anyone, I imagine) is mixed projection … and it has happened in the past.

 

BTW, the spell-checker accepts “drafting” but barfs on “draughting” (though not on “barf” apparently)

[David Clark 13Participant @davidclark13]

Hi There

When I took over Model Engineer, I am fairly sure that I was told we use first angle only so that is what I did when I did the drawings for the lubricator and Rina which have not been published yet. Looks like we should be using 3rd angle. I will see if I can get them changed.

Might not be perfect as we only have time to swap views over, not redraw.

 

regards David

 

[KWILParticipant @kwil]

David,

 

If you look at the drawings inserted in the early MEW mags they are 3rd angle.

[Peter GainParticipant @petergain89847]

David,

I do not like the Americanisation of our language & culture but (grudgingly) admit that “They” are sometimes right. 3rd angle projection is far more logical as the end views are adjacent to the relevant portion of the side elevation. Ie, the product is drawn as an unfolded box. We were using 3rd angle in the 19 fifties, surprising that anyone still uses 1st.

Architectural drgs often have mixed views, the side & end elevations & roof in 3rd angle but the floor plan drawn below is 1st. For buildings this is a logical method & avoids an inverted plan view.

Peter Gain.

[Eric CoxParticipant @ericcox50497]

I would have thought ensuring the dimensions were correct and non missing to be more important than which projection to use.

By the way, how were you able to make a ” sample component ” if you didn’t understand the drawing ? 

[Gordon WParticipant @gordonw]

I’m an ex draffy, did it most of my life. Always get confused over projections. Golden rule is if there can be any doubt, use an arrow to indicate the view. Drawings go all over the world and many standards are in use. Note to the ed, please put center lines on round bits.

[CirclipParticipant @circlip]

Snap Gordon, beat me to it, put “View in direction of arrer” on the drawing and avoid the confusion. Ex drafty also. In “Technical drawing” at school, we were allus brunged up wi First angle or “English” projection and when going to “Tech” it was a daily bone of contention between the two factions who worked in D/O’s where one or the other was the norm.

 

  The Arrer don’t lie.

 

   I think todays electronic Etch-a-sketch drivers would have a good cry if they got  graphite on their arms. Gawd elp us when some bright spark decides to start putting geometric tolerancing on our “Toy” drawings.

 

  Regards  Ian.

[David Clark 13Participant @davidclark13]

Hi Eric

We used the drawing as a guide and making the component helped us to understand it.

regards David

 

[James BParticipant @jamesb]

Hi David,

 

I work in the Automotive industry as a CAD designer, have worked for most of the large OEMs on a contract basis over a number of years. I many cases now, a 2D drawing is not even used, the 3D CAD being the master data. The systems used provide highly controlled surface data, that the toolmakers generate cutter paths from on thier CNC machines, and the parts are generated from this.

 

2D’s are still used, but mainly for inspection, i.e. the critical dimensions for fit and function on the part. These are always (in my experience) 3rd angle – with the geometric tolerancing included…

 

Although I feel 3rd Angle is much more logical, I don’t think there would be any confusion if we established a ‘standard’ for the magazine and stuck to it.

 

Also, I don’t agree with some of the views in the magazine recently about the poor quality of drawings – this is, after all, a hobby, and as long as you can make the component, all is well. Personally, I have never found any issues that could not be worked out with a little thought, that in some cases is some of the appeal of the hobby (for me anyway).

 

Circlip – Sorry. I am, ashamedly, an Etch a Sketch driver… but I did do a ‘proper’ draughtsman apprenticeship – and I only do this to pay the bills…!  GIven the choice I’d be in the workshop on my old, non computer controlled machines…

 

James

 

[Peter G. ShawParticipant @peterg-shaw75338]

Well now, as a rank amateur with no training on drafting other than what I was told (ie didn’t particularly learn!) at secondary school, I have had to teach myself.

 

Tubal Cain, in his book Workshop Drawing (WSP13) says that he finds 1st angle instinctive and always uses it. I have to say that I don’t find it instinctive, rather I find 3rd angle instinctive in  that to me it makes absolute sense that when drawing a view at right angles to the main view, that view should be as if I was looking at the relevant side, and placed at the same side. (Sorry if that doesn’t make sense – I know what I mean!)

 

I do agree though, that what is extremely important is to show the appropriate 1st/3rd angle symbol to avoid ambiguity.

 

Regards,

 

Peter G. Shaw

 

ps. Especially to Circlip. I use a CAD program. Occasionally I may do a pencil sketch, but if you could see the poor quality of my handwork, you would immediately realise why I use the CAD program. I have no doubt that I could learn to do proper pencil & paper drawings, but at my stage in life I am simply not interested in doing so when the CAD program does it so much more easily, and allows me to develop my ideas without having to use an eraser and shield. 

 

[David Clark 13Participant @davidclark13]

Hi There

Looks like 3rd angle is the winner.

Bear in mind that we can’t redraw all drawings to 3rd angle.

We will still have to rely on contributors.

However, when I get a bit of spare time, I will add some notes for drawings to  the contributor guidelines.

regards David

 

[Tony MartyrParticipant @tonymartyr14488]

All the drawing that I now see that originate from an automotive customer based in China are in first angle projection.

During my apprenticeship in the 1960s all drawings for commercial and admiralty turbine and gearing work was in 3rd angle

Now most design work is carried out in SolidWorks or similar software which makes much of the discussion irrelivant

As long as any project uses a consistence policy and all drawings are marked with the projection used then engineers should be able to use both or either.

Tony M 

[VersabossParticipant @versaboss]

Hi all,

I think I have to drop in here too. Like P.G. Shaw, I cannot draw manually (and not much better with CAD!).

But in the last 10 years I saw a lot of drawings for parts I had to produce, and these were always in first angle. Sure I first had to look at the definitions in Wikipedia to be sure.

The way I was teached to look at them was like that (hope I can explain it clearly):

Lay the part on any of the 3 views, so that the picture corresponds with what you see. Then tilt the part over to the 2nd drawing, and tilt again  to the 3rd.

With tilt I mean e.g. keep the edge on the paper and rotate the part 90 degrees around that edge. All clarity removed now… For me this method is intuitive also.

Well, no matter how it is done in ‘our papers’, but – as others said before – it should be marked clearly.

Greetings, Hansrudolf

[Sub MandrelParticipant @submandrel]

Hi Dave

 

I vote 1st angle, But the best thing is to make sure every drawing has the little truncated cone in a corner – no doubt that way!

 

I was amused that one of Dave Parkes drawings in the issue before last had first and third angle mixed in the G/A. Poor Dave had obvioudsly gone to pains to get it right from his text, but it looks like someone else re-arranged it!

 

 

Neil (B at O-level in GED – Geometric Engineering Drawing, despite my blunt pencils!)

[Ramon WilsonParticipant @ramonwilson3]

Lots of good comments here. First or third ? both are acceptable but I have to agree most with the concept of whatever system is chosen  stick to it.

 

I dont want to steal the thread but as we are on drawing style possibly this is the time and place to air the one thing on drawings that really gets to me and one that I simply don’t understand why it continually happens. That is – the use of mixed (and sometimes several) datums. I find it most irritating when something has been dimensioned from a surface that has no exact reference to the main datum when it actually needs to be.

 

Other than reading a drawing I have no training in draughtmanship as such but what is so difficult about dimensioning from two fixed points. Is there a really good reason for this practice that so far is not apparent to my old grey cells.

 

Am I alone in this or does this bother anyone else?

 

Ramon

[Steve GarnettParticipant @stevegarnett62550]

I don’t mind which is used – as long as whoever does the drafting puts the appropriate BS projection symbol on the drawings, because then it’s clear to anybody (or at least it should be) as to what you can see in the relative positions – rather better than just sticking arrows on, or whatever…

 

Inevitably I had to create a pair of these for SolidEdge, because I couldn’t find any that came with it. I have these as library parts drawn to the recommended proportions, and if anybody wants a copy of these they are welcome to them – send me a private message and I’ll email them.

[Ian S CParticipant @iansc]

Could be that some drawings are submitted by Model Engineers who in their other life have no engineering experience at all, including no drawing at school. They proberbly can’t understand what all the fuss is, they just scratch there heads and muddle on. Ian S C

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