Why are rulers measuring inches usually divided by multiples of eight?
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a.palfreyman
pfm Member
My 'Little Oxford Dictionary' of 2003 says a ruler is someone who rules, or is a straight strip used in measuring or drawing straight lines...
mansr
Objectionist
A printed copy of Webster's dictionary from 1971 agrees.
miktec
retired
Of the 5 UK schools I attended from 1954 onwards, all teachers referred to the marked pieces of wood we had to use for measuring as 'rulers'.
I only encountered the word 'rule' in relation to measuring at Secondary School when we were taught to use a slide rule in Maths.... and one Metalwork teacher who referred to the metal version as a 'rule' (correctly I believe)
We were frequently punished with rulers (12in not 6in as a rule) - applied to the hand, or the back of the leg during the short trouser season.
I only encountered the word 'rule' in relation to measuring at Secondary School when we were taught to use a slide rule in Maths.... and one Metalwork teacher who referred to the metal version as a 'rule' (correctly I believe)
We were frequently punished with rulers (12in not 6in as a rule) - applied to the hand, or the back of the leg during the short trouser season.
awkwardbydesign
Officially Awesome
I think in Imperial, but work in metric. But then, I am 73.
a.palfreyman
pfm Member
NO. Slide rules are useless. By my estimation, they keep moving when you try to measure or draw a line... 
martin clark
pinko bodger
Scale Rules are where it's at. Much fun.
Play/draft with a few for long enough and you may find you can (freehand) sketch-to-scale... quite closely-enough.
(I also have a lizardy bit of the brain which is entirely-wasted hosting the automatic 'scale-conversion vs print-copier zoom/reduction paper size' translation table)
Play/draft with a few for long enough and you may find you can (freehand) sketch-to-scale... quite closely-enough.
(I also have a lizardy bit of the brain which is entirely-wasted hosting the automatic 'scale-conversion vs print-copier zoom/reduction paper size' translation table)
westsea
Retirement present
Scale rules are great and I agree with you freehand sketching to scale is handy
A bit of self indulgence coming up ....as an apprentice draughtsman in 1953 my first job was preparing arrangement drawings at 1/4 inch to foot. Printed as blueprints, but not for long. Scale rules were a thing to be treasured, as were Riefler drawing instruments and a book of Smoley's log tables from 0 to 200ft. No calculators, only log tables for more accurate calcs, and slide rules for first approximations.
Although clumsy, yards, feet and inches related to a more human scale than metric, I missed them when it all changed.
martin clark
pinko bodger
^ Lovely stuff! Thanks for that : )
Although I started in the metric era I still fall back to imperial occasionally. Since we no longer have an Automotive industry in Australia I have progressed to working in rail. Rolling-stock is big and expensive so rail assets tend to be kept and up-graded for very long periods of time. Subsequently I have found myself using feet and inches for general talk and Metric for serious design work. In Australia we have 3 rail gauges 5’3”, 4’8 ½” (standard gauge) and 3’ 6”. It’s just awkward to say 1600 mm, 1435mm or 1067 mm, just a s a typical freight bogie has 8’ axle centres rather than 2438 mm. Although in Europe they do have a "meter" gauge mostly for light rail & tram networks, so it cuts both ways I suppose.
Scale Rules are kind of cool. I still have two of the triangular ones at home. One is with architectural scales (my mistake for not checking before buying) and one with the Engineering scales 1:2, 1:5, 1:10, etc. Unfortunately, these days as we no longer have trainee draughters but use younger engineering graduates that have only ever used CAD. They seem to think the non-standard scales like 2:3, 7:1 etc are OK since it’s just a click of a button to rescale a drawing. If I’m checking their work I also argue that copying the views on to a bigger sheet size as also allot easier. When I started on the drawing board that would have been a redraw from scratch.
When I started most of the draughters were ex machinists and tool makers who did a little extra night schooling to get higher Engineering qualifications. We understood drawings and work shop processes before we started making drawings.
LPSpinner
Scale Rules are kind of cool. I still have two of the triangular ones at home. One is with architectural scales (my mistake for not checking before buying) and one with the Engineering scales 1:2, 1:5, 1:10, etc. Unfortunately, these days as we no longer have trainee draughters but use younger engineering graduates that have only ever used CAD. They seem to think the non-standard scales like 2:3, 7:1 etc are OK since it’s just a click of a button to rescale a drawing. If I’m checking their work I also argue that copying the views on to a bigger sheet size as also allot easier. When I started on the drawing board that would have been a redraw from scratch.
When I started most of the draughters were ex machinists and tool makers who did a little extra night schooling to get higher Engineering qualifications. We understood drawings and work shop processes before we started making drawings.
LPSpinner
martin clark
pinko bodger
^ Good stuff right there.
I was fortunate, in that at the time I got taught the how-to of 'technical drawing' at c.11-13 (mid-80s), the tutor was actually an ex -Vauxhall Engineering draughtsman, very late-entry into his second career, who (1) really didn't much care for being told what he should teach , when it was an utterly-trivial subset of his experience, & he though t otherwise; and (2) consequently incorporated all sorts of stuff way-off-the core-curriculum, in terms of raw geometric construction with straight-edge+ compass* & enthused upon the how and why, drawings are ...composed, and what lies behind: why being able to convey information concisely in an accurate drawing matters, what in that drawing might matter - all the rest.
And did so in a way that, oh, made dull stuff like 'geometry' - actually a very real, interesting, thing to explore for it's own sake.
A rare gift.
and good golly - I count that an utter, memorable privilege; one that translated directly, a few years later via my appreciating the joy of generating by hand a really good drawing: to harness that taught ability to conjure-up a striking/wilfull (but accurate) projection: well that ..did well -enough along the way in bits & competitions, paid off my overdraft before I completed the second degree.
I can still do the method of generating an arbitrary-number of sides polygon, from a given facet; can picture it now. Only needs a compass, and straight edge. Later at Uni, a self-set idiocy of trying a 3-point perspective with a curved projection plane(s) - joy %) But I could attempt it - because someone who really cared, loved the geometry that lies behind, years earlier - had actually given me enough grounding in, and the raw inkling, to approach the task.
I've always appreciated that.
I was fortunate, in that at the time I got taught the how-to of 'technical drawing' at c.11-13 (mid-80s), the tutor was actually an ex -Vauxhall Engineering draughtsman, very late-entry into his second career, who (1) really didn't much care for being told what he should teach , when it was an utterly-trivial subset of his experience, & he though t otherwise; and (2) consequently incorporated all sorts of stuff way-off-the core-curriculum, in terms of raw geometric construction with straight-edge+ compass* & enthused upon the how and why, drawings are ...composed, and what lies behind: why being able to convey information concisely in an accurate drawing matters, what in that drawing might matter - all the rest.
And did so in a way that, oh, made dull stuff like 'geometry' - actually a very real, interesting, thing to explore for it's own sake.
A rare gift.
and good golly - I count that an utter, memorable privilege; one that translated directly, a few years later via my appreciating the joy of generating by hand a really good drawing: to harness that taught ability to conjure-up a striking/wilfull (but accurate) projection: well that ..did well -enough along the way in bits & competitions, paid off my overdraft before I completed the second degree.
I can still do the method of generating an arbitrary-number of sides polygon, from a given facet; can picture it now. Only needs a compass, and straight edge. Later at Uni, a self-set idiocy of trying a 3-point perspective with a curved projection plane(s) - joy %) But I could attempt it - because someone who really cared, loved the geometry that lies behind, years earlier - had actually given me enough grounding in, and the raw inkling, to approach the task.
I've always appreciated that.
Nowadays drawings are all done from a 3D model that is used to project 2D views on to a drawing sheet. Projecting views is all done “under the hood” by the computer. Fully understanding the difference between first angle and third angle is not so critical when initially laying out a drawing with CAD but it can make a major difference in knowing how to read the drawing from either a first angle or third angle perspective later after its printed.
Like you Martin, having studied basic geometric principals still helps greatly in setting up a useful 3D CAD model. Understanding a few basic principles can help visualise geometry and layout the foundations for good modelling discipline. This will creating a 3D model which is truly representative of the “design intent”. While we may not use a 6H “clutch” pencil and “Rotring” drafting pen set any more for laying out and develop design drawings, ultimately these skills also translate into the “CAD” world and it shows when you see a drawing that is clearly dimensioned and easy to understand.
Also projecting section views on complex parts can change the view perspective entirely purely by the direction of the section arrows.
LPSpinner.
PS: How the Heck did this conversation get so off topic.
Like you Martin, having studied basic geometric principals still helps greatly in setting up a useful 3D CAD model. Understanding a few basic principles can help visualise geometry and layout the foundations for good modelling discipline. This will creating a 3D model which is truly representative of the “design intent”. While we may not use a 6H “clutch” pencil and “Rotring” drafting pen set any more for laying out and develop design drawings, ultimately these skills also translate into the “CAD” world and it shows when you see a drawing that is clearly dimensioned and easy to understand.
Also projecting section views on complex parts can change the view perspective entirely purely by the direction of the section arrows.
LPSpinner.
PS: How the Heck did this conversation get so off topic.
martin clark
pinko bodger
It's not off-topic- it's the way sometimes 'we' get to the good stuff
Start with discussion of a singular dimension foible ... every response since progresses the discussion of the why, and how, and some- what underlies some of those choices. : )
(ps 2H blue leads in the old heavy Staedtler clutch, then FaberCastell for my prefs - final on PET drawing film, if poss.
still got the kit...)
Start with discussion of a singular dimension foible ... every response since progresses the discussion of the why, and how, and some- what underlies some of those choices. : )
(ps 2H blue leads in the old heavy Staedtler clutch, then FaberCastell for my prefs - final on PET drawing film, if poss.
still got the kit...)
cj66
pfm Member
How big is the educational (state schools) window on being taught both metric and imperial, plus being comfortable converting from one to other in your head?
That would be mostly 70's schooling for me, with a blob of 80's on top and then college.
Most peeps I talk to are firmly fixed in one or the other camp.
Back to the calibration on the imperial side of a rule, mine all have at least one inch marked in 16ths another in 8ths and the rest in 10ths. One is graded as follows, 32nds for 3 inches, 64ths for one inch and 16ths for the rest.
That would be mostly 70's schooling for me, with a blob of 80's on top and then college.
Most peeps I talk to are firmly fixed in one or the other camp.
Back to the calibration on the imperial side of a rule, mine all have at least one inch marked in 16ths another in 8ths and the rest in 10ths. One is graded as follows, 32nds for 3 inches, 64ths for one inch and 16ths for the rest.
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with another guy I did a commercial implementation of PostScript. This language includes 2 dimensional coordinate geometry, and matrix transformations, allowing arbitrary rotates, scales, skews, movement.
The base units of PostScript are printers points, of which there are 72 to the inch.
The base units of PostScript are printers points, of which there are 72 to the inch.
Barrymagrec
pfm Member
We were slippered - you must have gone to a technical school.
awkwardbydesign
Officially Awesome
Ah yes, one of my few* O levels! I ended up teaching myself sign-writing, and still have my scale rules.
* Plus metalwork (just like Rodney Trotter!), physics, maths and English language. Then I left.
And it was the cane for us - grammar school.