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bennyboy86

Metric to imperial

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bennyboy86

hi all,

 

So my boss has asked me to set up a job to be done in the USA, we australian and use metric so needing to convert stuff to imperial, i have figured out that using the dimstyles and changing it to the settings in picture, has gotten it correct.

 

my question is, the measurements need to be quite exact down to the mm, so one dimension is 297mm........coming in at 11.69 inches.....but how far do i go? is 11.7 fine or should i go 11.69 or further? in mm can get right down but not sure how to go with inches?

 

hopefully this makes sense.....

 

thanks in advance...

 

Capture.JPG

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bennyboy86

noticed that architectural unit format gives me inches with fractions as the precision..... so is x/16 accurate enough? or x/32???

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Dana W

A suggestion, use primary and alternate units in your dims, than you don't have to convert your drawings.

 

Another suggestion, make sure you have to use fractional dimensions. Decimal imperial units are also available. 1.25" as opposed to 1 1/4"

 

I also suggest you convert a couple of fractions to mm in order to get a feel for how accurate you need to be. 1/32" is pretty big in some industries, like electronics, but does not even exist in the timber framing area. For instance 1/32" = 0.79375mm which is greater than 75% of a millimeter.

 

1/256" is the largest fraction that is less than 0.10mm at 0.0992187mm

 

You can use an online converter to check a few out, like this one.

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bennyboy86

yeah after looking and thinking about it, was going to go with 1/16, as anything smaller is just not worth it, like you said 1/32 is only .8mm....

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Dana W
yeah after looking and thinking about it, was going to go with 1/16, as anything smaller is just not worth it, like you said 1/32 is only .8mm....

 

Again, it depends on what you are building. Like I alluded to, a timber framer will laugh at dimensions smaller than 1/8". They just don't matter when using circular saws and pneumatic nailers. Then, a cabinet maker will agonize over 1/32" to make the work fit cleanly.

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Dadgad

Will you be sharing .dwg files with them stateside, or PDFs?

What metric level of precision do you use on your Aussie projects?

On the work I do for the Aussie market we use mms, no decimal places for high rises, 75 stories and the like.

Will these be fabrication drawings, and if so, where is the fabricator?

 

As stated by Dana, it would help to understand the nature of the project.

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BIGAL

I would be more worried about 11.69" If you supply a 300mm part it will fit sloppy in a 12" Hole. Do you have to supply to the preffered size ie 12" which is 304.8 mm. Same with all the structural steel sizes a 4" beam is 101.6mm but here in AUS it would designated as 100mm beam and when measured it would be 100mm.

 

I think you need to ask your Boss the questions above are you supplying a hybrid part matching true inch sizes.

 

Cars are sold all round the world in both metric and imperial for bolts etc the only one thing you can buy any where in the world is a tyre which still has inches as wheel diameter, my car fully imported all metric has 17" wheels.

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bennyboy86

its steel fabrication, we usually accurate to the whole mm, most likely be sending DWG's once Issued for construction to make it easier, i have been given free range to draw as boss doesn't know much about cad work, so am using my original standards and details which are mm and my overall plans and slightly tweaking them to be either whole inches or to the half inch....we are using shipping containers which are measured by feet and inches to begin with so not hard to make my stuff fit inside, only having to change them by 5-10mm so not to bad just have a converter open on my second screen as im going and its working out pretty good.

 

the only thing that comes built is the shipping container everything inside is fabricated to suit each job, eg overall lengths etc. so making the items fit to inches is alot easier then i originally thought.

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bennyboy86

as you mentioned about the beam size bigal, could someone point me in the direction of a USA supplier of rectangle hollow sections? usually i use a 100X50X3 RHS but that is Australia standards.....

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Dadgad
as you mentioned about the beam size bigal, could someone point me in the direction of a USA supplier of rectangle hollow sections? usually i use a 100X50X3 RHS but that is Australia standards.....

 

These screenshots are from the ProSteel database, I have highlighted an RHS very close to what you described, I hope that helps you.

aisc rhs.jpg

aisc rhs imperial.jpg

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bennyboy86

thanks for that, late yesterday open internet explorer (shocking i know).....and set google to search usa not aus and finally found suppliers, going with the 4x2x3/16 (inches) HSS..damn i miss prosteel loved using that

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gazza_au

type STL_USA once loaded or STL_AU for Aussie....

 

Gazza

Steel Lisp.zip

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dbroada

I was always involved in mechanical engineering so two decimal places metric and three decimal places imperial - so totally inappropriate for you BUT

 

I have been involved with a particular project built both in the UK & the USA. The one thing I learned - ignore the people who want it easy for both systems. The managers can argue as much as they like, you will always have a compromise somewhere. Decide who is doing the building and work that way. If you end up with 19.864mm, hard luck.

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ReMark

Is the size available "off the shelf" or is it a special order? Many firms do not stock what they consider to be seldom used sizes and end up charging the customer a premium for supplying such a size.

 

What is this being used for anyway?

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Dadgad
thanks for that, late yesterday open internet explorer (shocking i know).....and set google to search usa not aus and finally found suppliers, going with the 4x2x3/16 (inches) HSS..damn i miss prosteel loved using that

 

You probably know that section is about 50% thicker than the one you say you favor in Australia, and that even the 4x2x1/8 is slightly larger than your usual RHS profile. :|

Edited by Dadgad

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BIGAL

Let us know which one you choose metric, feet or painfull metricfoot for your structure.

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Tiger

Wait, there's a "metricfoot" as well? What on earth is that? And why??

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RobDraw

From Wikipedia:

 

Metric foot

A metric foot is a nickname occasionally used in the United Kingdom for a length of 300 millimetres (30 cm). The 30 cm metric ruler was of a similar length to the traditional 12-inch (one foot) ruler, so hence the term 'metric foot'. A metric foot can be divided into twelve "metric inches" of 25 millimetres (2.5 cm) each.

 

Which leads me to the same question, "Why?"

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nukecad

Why?

 

Because like the US, here in the UK the general populous resisted metrication for a long time, and some still do.

 

To the layman or laywoman there is no visible difference between a 1 foot rule and a 300mm rule, and for what they were using them for there was no difference between 1 inch and 25mm either.

e.g. for dressmaking, wallpapering, cooking pot sizes etc. and most other houshold based activities any inaccuracy just gets adjusted at the end.

(Are you bothered whether your cake tray is 8" or 200mm diameter?)

 

We also talk about metric pints (for milk and canned beer - draught beer still comes in imperial, UK pints).

We still give driving distances in miles, as do most road signs. But our speedometers are in km/h.

And I'm sure you've heard of the metric mile (1500 metres).

We still give peoples heights in feet and inches, and their weight in stones (although this is gradualy changing to cm and kg respectively).

 

Hey, we've only been a metric country for 45 years - these things take time :P

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RobDraw

Combining the two systems is not definitely going to speed things up, though.

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