Drawing projection, first or third?

[Steve GarnettParticipant @stevegarnett62550]

Posted by Ramon Wilson on 24/02/2010 22:57:04: 

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?

 

 

It’s generally sloppy drawing practice, although there are allowable exceptions for drawings where it gets crowded. The exception that’s mentioned in the BS is called ‘superimposed running dimensioning’, but even that is based on parallel dimensioning, which always starts from a fixed datum. The stuff that is a bit of a pain is chain dimensioning (presumably what you are complaining about) and that can be made even worse by combining this with the other sort, because then you get dimensions all over the place, and probably some redundancy as well.

 

The system I use mostly is superimposed running dimensioning from a fixed datum, running in two directions, if it’s for parts that are generally square-ish, and a slight modification of this for turned ones. This effectively gives you dimensioning by co-ordinates, which is what most people with access to a DRO seem to prefer, anyway…

 

But as you’ve already said, really the important bit is that the result is unambiguous, and as easy to understand as possible, whatever system is used.

[CirclipParticipant @circlip]

Dimension from two datum planes only. Yep I was taught this at school, but in the REAL world of imparting numerical information for manufacturing, logic takes over.

 

  OK Ramon, consider the frame plates for a loco. When you start marking out from one end, which is more important? Having the cut outs for the wheel centres in an exact position to the frame end or to EACH OTHER and additionally should the hornplate holes be dimensioned from the frame end or the hole they are dispersed around??

 

  I remember on one forum that a Drafty working for BR mentioned that if he dimensioned using sub datums he would get a “Talking to” by his superiors. Believe me, I have been responsible in the past for having items made as a sub contractor and supplied to BR and the worst part at the start of the chain was to have to translate some ( quite a lot) of the said renderings supplied by the Ivory tower into PRACTICAL manufacturing information.

 

  It’s no good that some, who are activey engaged in the generation of drawings in a manufacturing area to state BS (Bu** S***) whatever to the attendant masses, but in trying to give instructions to someone who hasn’t had the luxury of beng taught how to do it “Properly” the simplest non ambiguous drawing should take precedence.

 

  You want to “Play” with the various “Instant Draughtsman” programmes?? Fine, but leave the pins and eggs in the drawer when trying to teach some of us teeshirt/video makers the ropes.

 

  And before someone states the old nugget “A drawing saves a thousand words” Get real. A couple of lines of notes on a drawing saves any confusion if notated correctly, — Oh heck, I am ASSUMING (yes, I’ve heard that one too) that the subject can actually read.

 

  Regards  Ian.

Edited By Circlip on 25/02/2010 07:34:42

[David Clark 13Participant @davidclark13]

Hi There

I have emailed the illustrator.

Where possible we will do drawings as third angle.

Won’t be possible to redraw everything bu it is a start.

regards David

 

[Ramon WilsonParticipant @ramonwilson3]

Hi, thanks all for the response – helpful as always to see others thoughts but  Ian, lets get this in perspective.

 

I don’t have a problem when its chain dimensioning providing it relates from or to the same source eg as you quote, the horn slots on mainframes – dimensioned from one end, then to each other or indeed the horn plate holes dimensioned to the edge of the slots or from the centre line. Straightforward stuff.

No it’s when for example one of those slots is ‘suddenly’ dimensioned from the other end of the original datum. There may be good reason for this ‘transfer’ but I’m b—–d if I can see it particularly when other parts have to fit.

 

I accept that the average guy with no training, offering drawings for our pleasure all done at home with pen and paper or computer is going to make the odd error. Let’s face it, like machinists don’t all draughtsman from time to time? But the habit of transfering  seemingly for the sake of it helps no one especially the unwary and no, don’t assume anything – I can read a drawing annotated or not but maybe others less able may have difficulty realising the significance of the position of something a bit to late to rectify an uneccessarily made mistake.

 

This was certainly not about teaching anyone, grannies or otherwise, quite the reverse actually.

 

The implied question was simple enough – Is there a reason for it ? – and the specific one quite clear – Does this bother any one else? .  Obviously not in your case.

Kind Regards – Ramon

 

 

[Steve GarnettParticipant @stevegarnett62550]

Posted by Ramon Wilson on 25/02/2010 09:36:12: 

 

I accept that the average guy with no training, offering drawings for our pleasure all done at home with pen and paper or computer is going to make the odd error. Let’s face it, like machinists don’t all draughtsman from time to time? But the habit of transfering  seemingly for the sake of it helps no one especially the unwary and no, don’t assume anything – I can read a drawing annotated or not but maybe others less able may have difficulty realising the significance of the position of something a bit to late to rectify an uneccessarily made mistake.

 

I have no problem with annotations, and absolutely no problem with providing notes either. Do draughtsmen make mistakes? Is the Pope a Catholic? For me, the acid test of whether I’ve made a drawing sensible, unambiguous and usable is when, several months later I have to re-manufacture what’s drawn. The rest is obvious…

 

And Circlip, I do them pretty much to BS. It may not be perfect, but what the heck, it’s a standard. And without it I can absolutely guarantee that there would be a good deal more confusion than there already is. I started out with this whole drafting business at school where I was fortunate enough to be taught by an ex-draftsman rather than just an academic, and everything we were taught was based on it being practical to use, not just straight out of a book. So that’s 35 years doing them the hard way on paper and about 8 doing them with a variety of CAD packages, none of which I’m entirely happy with. But when you have somebody leaning over your shoulder saying “what if…?”(this happened several times yesterday), then I’ll accept the limitations, I think.

 

And as for your loco frame plates, I’d probably use detail drawings for holes relative to axles with the datum taken from the axle centre – simply because in the absence of any other information, I’d assume that this was how you’d reference them when you cut them. And put accurate axle centre information on the main frame drawing. That would be until somebody told me that it was impractical. Then, for heaven’s sake, I’d change the bloody drawing…!

[CirclipParticipant @circlip]

At least we all seem to be working on the common sense page,sadly due to pressures from the “Lets all go Metric” brigade, things went awry when some tried to “Double dimension” drawings A La Opus Approximus and others.

 

  Yes qualified Drafties DO make mistakes, and the economics of test building and checking  is a luxury that the toy comic trade can ill afford although to hear SOME of the complaints, you would think that it was intentional. Some of the day jobs of some muddlers must show perfection at all times??

 

  Regards  Ian.

[Ramon WilsonParticipant @ramonwilson3]

Well I think you’ve hit the nail on the head there Ian,

 

I have had four machining jobs over some thirty years. Three were in small jobbing workshops serving local industry the other in a larger but by most standards a small factory – ‘machine shop’ support of the main business of producing electrical terminals..

 

In the jobbing workshop, ‘mistakes’ – whether you happened to be concientious or not – were not exactly met with favourable comments. Whereas they can be overlooked in the larger environments in the small shop ‘time is very definitely money’. You get nowhere making mistakes!! The work, as varied as you can imagine, always ‘took too long’. Perfection then, or the attempt to be, came from contientiousness and a certain degree of self esteem. I make no apologies for having tried in that direction.

 

The factory on the other hand saw a different approach, much more laid back attitude to mistakes but the work, virtually most of which would fit in the palm of your hand, was of ery high tolerance that had to fit and work all carried out on basic kit so again an attitude toward perfection was required. Is this a crime?  Well if it is it’s not in my book.

 

To consider anyone I feel – no matter what their background – who expresses a desire to participate in this vast arena of ours as a ‘muddler’ seems not a little disparaging toward the hobby and it’s participants in general.  Not my idea of encouragement of those with desire to improve I have to say.

 

My apololgies to all for taking this off topic.

 

Regards – Ramon

 

 

 

 

[Steve GarnettParticipant @stevegarnett62550]

What I do tends very much towards your ‘small factory’ approach, and a lot of it’s developmental – hence the ‘what ifs’ and me having to make some of the stuff too. But if we need larger quantities of anything, it’s straight off to CAM, hence the need for an acceptable standard of machine drawing.

 

But I don’t think that your comments are really off-topic at all. Even hobbyists place some value on their time, and attempting to construct anything from less than stellar drawings invariably takes longer than it would from ones laid out and dimensioned with at least some thought given to construction. Inevitably this is going to lead to an increased sense of frustration, especially for beginners. So I’d say that providing sensible drawings to an agreed format, and with serious thought given to dimensioning (the now out-of-date publication I mentioned earlier gives over about a quarter of itself just to this) is definitely the way to go. Just because people are hobbyists doesn’t mean that they should be treated in any way differently to anybody else machining at a distance from the designer, does it? Since the editor employs a draughtsman, then I don’t see why this requirement should even discourage people whose engineering skills are in excess of their drawing ones from submitting stuff for publication, either.

 

So having this as a timely reminder on a thread about the way drawings are presented seems entirely relevant to me.

[David Clark 13Participant @davidclark13]

Hi There

We employ an illustrator, not a draughtsman

and he has 5 or 6 magazines at least per month to do.

regards David

 

[Steve GarnettParticipant @stevegarnett62550]

Oh… are there any implications to this?

[CirclipParticipant @circlip]

Firstly Ramon, despite having a lifelong career in “Full size” engineering starting in the toolroom and through my own efforts traversing via the D/O to works management, I would ALWAYS describe myself as a “Muddle Ingineer”, so I would never try to insult anyone who has a more normal type day job and then chooses to impregnate their fingers with sharp bits of metal.

 

  One for Steve, ever worked with  “Contract Draughtsmen”???? One of the problems in working in any “new” firm is finding the different working standards and manufacturing capabilities. My own training “Spoiled” me by dropping me in with “Old Ingineers” (Thank heavens) but the range of equipment for cleaving bits of metal was second to none, so having the grounding of HOW to cleave and WHAT to cleave with stood me in good stead to enable me to progress to “Design” tools, tooling and later components for both mechanical and electro/electronic product manufacture.I doubt that any of todays “Kids” could emulate that route in manufacturing cos the BASIC grounding is not there anymore.

 

  The problems I found with ALL the C/Ds I worked with was that they were shipped in to relieve an order “Glut” at the time, and then six months later when the jobs hit the shop floor, the land mines would start exploding. Their drawing skills were not the problem, but an alien (to their training) working enviroment didn’t help when “Dropped in” for a few weeks contract. I’m also sure that Steve will have been “Involved” with “Designers” whose best use for a piece of pointed graphite would be cleaning their ears out with it.

 

  The use of an “Illustrator” for the Mag. is not a problem PROVIDING the information given to them is correct from the outset. We had a superb “Tracer” in my first drawing office whose pictures were like works of art, (SHE was pretty fit too) BUT had she been asked to design a press tool would have had no idea despite working in that enviroment for many more years than I had.

 

 A basic rule I worked to when designing bits to be assembled on “The Line” was ( and don’t get your knickers in a twist over THIS one Ramon) make sure it can be assembled by monkies, and if you have a trained monkey, regard that as abnormal. Now I’m NOT insulting ALL shop floor workers, but many are motivated by ONLY the brown envelope at the end of the week, so making “Mindless tasks” had to be the norm and you NEVER stopped “the line” on pain of death, alarm bells and a Mexican wave of inactivity along the assembly benches is VERY frightening.

 

 So rounding back to the drawing representation, and given that you have to cater for all levels of mechanical knowledge from a road sweeper to a brain  surgeon and all points in between, although some “Authors” might have delusions of becoming ace Drafties at some future point and work to BS/ISO or whatever current standard, I find it far more important to have an unambiguous and DIMENTIONALY CORRECT representation that ANYONE can understand without having to think 1st 3rd or whatever (Where’s the truncated cone drawing).

 

  Summat else to chew and digest,

 

  Regards  Ian.

[Steve GarnettParticipant @stevegarnett62550]

Hehe… Because we ship stuff out, at least some of the time I reckon that I qualify as the contract draughtsman some of the time as far as the firms on the receiving end are concerned!

 

The last time we employed any outside contract help with a design was somebody to do a two-part plastic moulded case that’s pretty damn complex. And I have to say that the guy that did it was seriously good – the manufactured result was excellent, even though we had to send it to China to get them manufactured at an affordable cost. We’d definitely use him again.

 

But as far as the rest of it’s concerned, I think we’ve all agreed that overall clarity in drawings is what’s really of paramount importance, regardless of anything else at all.

 

 

[Peter G. ShawParticipant @peterg-shaw75338]

So, given that I am neither a trained draftsman nor a trained engineer, where does that leave me?

 

I have already said that I find 3rd angle rather more “natural” than 1st angle. I have also read, and try to understand and apply Tubal Cain’s writings in Workshop Drawing, WSP no 13. I also have Brown’s CAD for Model Engineers, WSP no. 29, which frankly isn’t that much help because my CAD isn’t the same as his. I know, for example, that partly due to the constraints of the CAD program, and the VDU, I do not do things as TC would wish, a good example being the use of heavier lines for the outline. I actually draw at minimum width because using the VDU, a heavy black line varies (and gets larger) if I zoom into expand a part of the drawing whereas a minimum thickness line remains the same no matter what the zoom. Also, I show dimensions, again due to the vagaries of the CAD, in different places to avoid clutter. Does this mean that anything I submit to the magazine will have to be completely redrawn?

 

I think the answer has to be that for “our” purposes, we have to understand that “our” people will have the ability to be able to make sense of what is drawn, and whilst it may be “wrong” to the trained draftsman/engineer as long as it is clear and unambiguous then surely that is the most important factor. Let’s face it, whilst on the shop floor, drawings will have to be, as Circlip says, suitable for untrained monkeys whose only interest is the brown envelope at the weekend, “we”, as amateurs, are doing it for our own interest, and thus will be prepared to invest our time in understanding the drawings, even if they are not to the relevant BS/ISO.

 

 Regards,

 

Peter G. Shaw

[Ramon WilsonParticipant @ramonwilson3]

Steve, Thank you for bringing such a  commonsense approach to this matter.

 

For myself, I have been fortunate never to have worked with monkeys, nor for that matter to be in charge of them, just good people who have held a pride in their work and what they do. (Don’t wear knickers either – preventative measure you know- if you don’t wear ’em you can’t twist ’em)

 

On the matter of self deprecation then by all means go ahead, be my guest – I certainly won’t lose any sleep over it but please leave me out of the equation. I learnt at an early age that deriding your troops is a negative and fruitless exercise.

 

As I said before the questions are simple enough – is there a good reason for the practice of transfering datums and does it bother any one else.

 

Steve has gone some way to try and answer the actual question – thank you.

 

Ramon

[David Clark 13Participant @davidclark13]

Hi There

Most things are redrawn anyway because of line weights and text sizes.

regards David

 

[Steve GarnettParticipant @stevegarnett62550]

Posted by Peter G. Shaw on 26/02/2010 12:08:21:

 

“we”, as amateurs, are doing it for our own interest, and thus will be prepared to invest our time in understanding the drawings, even if they are not to the relevant BS/ISO.

 

 Couple of points, Peter. The standards allow quite considerable latitude in what’s drawn, primarily because it’s realised that you invariably have different drawings for different purposes. And I still think that there’s a distinct limit to the amount of time that anybody would be prepared to spend trying to decipher less than helpful ones. Okay, it might make you increase your appreciation of the clearer ones, but does it really have to be like that? I would hope not…

 

There are a few snags though. Whilst I really don’t think that it’s that difficult to create basic drawings to an acceptable standard when it comes down to it, some of the more helpful drawings, certainly in terms of an overall understanding of what you are making, aren’t so easy. I have heard it said several times that most complex engineering drawings make far more initial sense if, for instance, some sort of axonometric projected view (typically an isometric one) is included, and I’m sure that’s correct within reason. But generally that doesn’t happen these days, and there is one very good reason for that – the now much more common inclusion of photographs with drawings. So really, you have to regard photographs in that sense as a part of the drawing set. And in many ways, that’s the saving grace of a lot of submitted projects – a decent set of photographs is a very important part of them, and, let’s face it, rather easier to do.

 

So as Circlip was saying earlier, you can’t just regard the drawings in isolation – annotations, notes, photographs and clarity in the text is just as important. A major skill  for an author to have under these circumstances is to be able to put themselves into the position of somebody else having to recreate their work – and I think that’s really the key to the whole thing.

[CirclipParticipant @circlip]

Yes Steve, and I’ll bet the designer had done one or two mould designs before?? How was he at laying out a Printed circuit board from the electronic circuit?? You have to compare apples with apples, so you are agreeing with my earlier statement on understanding the product. My PCB designs were manufactured in the UK, but my moldings were sourced from Taiwan, and although I had left mold design behind, only one of my moldings ever need a “sliding core” and that was for a product security feature only.

 

  Where it leaves you Peter is covered in the last three lines of my previous text. Draw it how you like, as long as the target can understand it. Another variable you have drawn into the discussion is which drawing Programme (Program for the collonials) you use. Although ALL the systems are derivatives from AutoCAD, to make them more user friendly, they all have their little quirks and have been generated to allow the non professional user a method of putting straight and square pitched lines on a “Paper” space. Pity the originators didn’t all use an interchangable compatible system of generating the drawings. One thing the electronic generation method HAS changed is the need not to have to draw to “Scale” IE. 2 :1 or 1 : 500 or the likes. Full size is Full size no matter how big or small the finished item is, so Davids point on lines and text smooths this out.

 

 

    Ramon, you REALLY should chill out.

 

  Regards  Ian.

[Gordon WParticipant @gordonw]

As mentioned earlier I was a draughtsman most of my working life, I’ve drawn on everything from linen and ink (and pounce) to autocad. I worked a lot as a contract draffy, on everything from lawnmower engines to oil production jackets (rigs). Always the main consideration is to draw , clearly and unambiguously, what has to be made. Part outlines thicker than the rest, center distances dimensioned, etc. etc..The tool operative should not have to calculate anything. I could go on. But this is a hobbey to most of us, and not worth all the hassle.

[mgjParticipant @mgj]

Personally I’m less worried about projections or conventions. I agree that getting it right does make for a lot of convenience, (Especially if one is used to working with the conventions in the past)

 

However, we are different from many production workers. Mostly we are making the whole thing, and we know what it should look like and what should fit. Unlike the man who is making 500 off of x  and x is simply an object with a set of dimensions, a part of a whole which he may never see.

 

Nor does it worry me frankly that someone dimensions from one line, or in steps of 1/2″ for example. I’m quite capable of measuring from a single edge or not, or even of letting my DRO do it for me, and of knowing when one might be critical and one not.

 

 

My concern is with accuracy – that the dimension you get off the drawing is actually the one that is needed to get a fit on the metal. We seem to have fallen a bit foul of that one just recently.

[Steve GarnettParticipant @stevegarnett62550]

Posted by Circlip on 26/02/2010 14:50:32:

 

Yes Steve, and I’ll bet the designer had done one or two mould designs before?? How was he at laying out a Printed circuit board from the electronic circuit?? You have to compare apples with apples, so you are agreeing with my earlier statement on understanding the product.

 

Oh yes, of course he’d done them before – he came recommended, and that’s all we wanted him to do. We do our own PCBs – have done for ages for loads of different products and that’s not a problem. So yes, understanding what you are producing is clearly important – possibly more important than anything else when it comes to drawing it in a meaningful manner.

 

I’m not quite sure where that leaves us with ME/MEW drawings. I mean, they all relate to different products, and they’re all originated by different people. Somehow one person has to reconcile these into a house style, not necessarily understanding what the significance of some aspects of the drawings are. With the best will in the world, this is surely not going to be an error-free process, is it?

 

Incidentally, in an idle moment this afternoon I had a careful look at the Edgar T. Westbury tailstock turret drawing (Jan 2010), and I don’t think that I would have dimensioned this in the way he did (assuming that it was him that did it) – it’s not entirely consistent either. And I’d say that it was short of a few centre lines, too. But could you make one from it as it is? Well I’d say yes, except that if you were creating the toolholder from scratch, you’d be scratching your head for a while!

 

[Peter TuckerParticipant @petertucker86088]

My preference is for 1st angle.  As our drawing teacher explained you place your object on the page, its in plan,  roll it up,  side elevation,  roll it right, end elevation.  Perfect logic.

 

Peter.

[Sub MandrelParticipant @submandrel]

I have a 1947 volume of ME here. The standard and clarity of the drawings is excellent, though sized for a much smaller page. Plenty of chain dimensions on the drawings for E.T.W.’s Seal, and only the essential ones given – but I defy any model engineer to struggle to ‘read’ the drawings correctly.

 

Somehow the drawings from those days look less stark, yet they work even at reduced size – this week’s free plan is another example – look at the tiny drawing of the sump!

 

I also have some two engraved views of an 19th century engine – you could build the full size thing just from these two drawings and a basic knowledge of steam engines.

 

In truth technical drawing is (or can be) an art, and needs to be done with an understanding and sympathy for the work to be done. I think Steve’s earlier post that explained how loco frame dimensioning needs to reflect the process of making them got it right.

 

I’m not sure someone in 2070 will get the same pleasure looking at today’s drawings that I get from those of 60 years ago.  One reason is the manual drafting uses a lot more line weights, computer drawings with just 1 or 2 line weights are dull and sterile. Another reason is that cross hatched sectioning, now disparaged, really enhances readability.

 

Not sure that takes the discussion forwards!

 

Neil W.

[Steve GarnettParticipant @stevegarnett62550]

Posted by Neil on 26/02/2010 21:15:35:

 

I’m not sure someone in 2070 will get the same pleasure looking at today’s drawings that I get from those of 60 years ago.  One reason is the manual drafting uses a lot more line weights, computer drawings with just 1 or 2 line weights are dull and sterile. Another reason is that cross hatched sectioning, now disparaged, really enhances readability.

 

Dunno what CAD package you’ve got, but Solid Edge uses 11 line types, all the colours of the rainbow if you want, and 9 different line widths. And if that’s not enough line types, you can create your own custom ones. Any limitations are with the user, not the software! Do I use coloured lines? Yes I do sometimes – because we do stuff with weird cross-drillings, and it often makes the intersection points easier to see, certainly at the draughting stage. Sometimes I even print them out like this, although usually by the time we’ve got to a final drawing I leave them black.

 

Hatching. Hmm… we haven’t touched on that. I’d agree that we don’t see so much of it these days, but maybe that’s because we don’t see so many sectioned drawings? In fact hatching is a lot easier to do effectively on a CAD system than it ever was by hand, and if it significantly enhances something, then I’ll use it anyway, because I don’t care about being disparaged that much! What I prefer though is that the hatching should have a relatively light line weight – I don’t want it looking like the rest of the construction lines.

 

As for the loco thing – all I did was apply what I thought was common sense, based on manufacturing lots of small things with holes in (not locos!) from drawings. And in a way, I think that’s important; you only really appreciate what it is you need from a drawing when you have to put one into practice. On that basis, I’d say that most successful engineers are a lot closer to being able to produce good drawings than they might perhaps realise, even though they don’t think they have the skills. What’s important is to make notes during the manufacturing process regarding what’s not so easy, and modify your drawings accordingly. After a while, you intuitively sense what’s more likely to work, and generally make less mistakes – and clearer drawings!

 

And as a footnote to what I said above about Edgar T. Westbury’s tailstock turret, I’ve now discovered that the drawing as presented in January is incomplete in some rather important ways, mainly concerning the aforementioned toolholder and details of its construction. I don’t have the original article it was based on, but I very much get the impression that the version of the plan that myhobbystore sell contains the missing information. Perhaps somebody who has the original article could confirm this?

 

[Sub MandrelParticipant @submandrel]

See what I mean only 9 widths Seriously though, look at the drawings in ME today and you will rarely see more than one or two weights being used, however manty are available.

 

I make do with corel draw, and that’s got almost unlimited line widths and styles – I can even fill with tesselated escher lizards if I want. It’s far from a CAD program, but I really hate using things like Autocad with their incredibly steep learning curves.

 

Perhaps its about time that someone with a good understanding of these things did a review of the competing CAD programs out there, from freeware to the top end stuff. Not a ten-part series, but a good overview with a feature comparison matrix.

 

Neil

[Steve GarnettParticipant @stevegarnett62550]

Posted by Neil on 27/02/2010 21:06:16:

See what I mean only 9 widths Seriously though, look at the drawings in ME today and you will rarely see more than one or two weights being used, however many are available.

 

I had a look in my old PD7308, which pretty much predates the CAD revolution (although not completely) and it strongly suggests that only two thicknesses of lines are recommended to be used, the thicker one being twice the thickness of the thin one. For other differentiation, it promotes different line types, rather than weights.

 

What it says is that thick lines are for visible outlines and edges, and thin lines, in various forms, are for almost everything else. The only exception stated (although there may be others I’m not aware of) is that chain line used on cutting planes should be thick where they change direction, and at the ends.

 

And I think that this is pretty much what you are seeing. Now, I don’t have a more up to date version of this (although I’m looking into getting one), so I don’t know yet whether any of this advice has been superseded. Personally, I hope that it has – for instance, I mentioned hatching weight above, and that’s one area where at least an extra thin line wouldn’t go amiss, IMHO.

 

As for tesselated escher lizards – I suppose that somewhere, there must be a suitable mechanical device where it would be appropriate to use these as cutaway hatching, at the very least. I don’t think that I’m going to lose any sleep over it though!

I remember using Corel Draw in the past for the odd thing, and I also recall that I never really got on with it that well. In comparison with a few of the older CAD packages, like Autosketch, I suppose it didn’t do that badly, although it never had anything like the scaling possibilities of the latter, or quite a few of its other useful features.

But in comparison with something relatively modern, like Solid Edge 2D, which is a free download and way more than adequate for the vast majority of normal home machining purposes, I’m afraid that Corel Draw is nowhere in it at all. Once you’ve got to grips with the relationship manager, and a few more of its neat dimensioning tricks, you’ll never use Corel for anything like machine drawing again, believe me. There’s a good chance that anybody into 3D CAM on a mill would ideally want a little more, but for them there’s always Alibre, and a few other apps. That’s not something I’ve ever really got into; at a bare minimum, it would have to wait for my complete retirement when I could concentrate on it rather more, I think.

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