Metric scale questions

[Mark Van]

I am making metric versions of my plans, and I was wondering what would be a convenient scale to use, I have never built anything using the metric system before, and I don't know what is considered standard.
The plans are currently 3/8" to the foot and 3/4" to the foot, the closest I can get to that in meters is 3/10 scale and 6/10 scale. Would that be a convenient scale to build from, or should I use another scale?
I could make the plans any scale that I want, but I need it to fit the paper size.

[John E Hardiman]

Yes, you can get metric scales.

http://www.forestry-suppliers.com/product_pages/view_catalog_page.asp?id=5937

But if the plans are already scaled in english measurement....why bother to convert? :confused: Just asking for trouble IMHO.

Unless you are look to find a metric scale for direct reading. Then..

3/8" = 1' converts to 3/8 = 96/8 ==> 1:32

3/4 = 1' converts to 3/4 = 48/4 ==> 1:16

Neither of these is a standard metric reduction. See ANSI Y14.100 (ex. Mil-Std -100) I believe.

[htom]

3/8":12" = 1:32, 3/4":12: = 1:16

I think you meant 3/100 and 6/100?

I have no idea what "standard" is in metric modeling, probably 4/100, 5/100 or 10/100. Somehow 31.15/1000 doesn't seem "natural".

[Uncle Duke]

From the above - you could use 30mm -> 1 meter for approximating the 3/8" (1/33.33333)
Double for the 3/4", of course.

[bennieboat]

hi Marc,

I measure and think and draw metric
I learn to see and read plans that mention feet and inches

I try not to translate (disaster will strike)

what are your plans about? and how complex is it?
are exact dimensions essential? or just comparisons and proportions

convenient scales ... that is:
plans with real life dimensions, no scaling

and then the translated scales will generate strange measurements
like 91.4 cm (~3 feet)
you could cheat and say: 4 inch is 10 cm

and I don't have a clue what you mean by 3/10 scale (or 6/10 scale)
is that: everything should be 3.3 times bigger in real life?
if so, then that is not not not convenient
or is that: 3 inch is 10 cm? that is not not not convenient

but I think that anything with 3 or 6 or 12 or 24 in it
is ever going to be metric thinking ;-)

a translater:
http://www.eslus.com/Gizmos/inchcm.html

you could try a scale where 3.3 feet in reality is 2 inch on paper
for buildings and large ships
to imitate a scale where 1 meter is represented with 5 cm

I think you should put (translated) measurements in your plans in centimeters
do not use meters (this won't cause translation faults and nobody is confused)
for me, 225 cm is a no brainer ( 2 metres and 25 cm )
even strange measurements, like 487.7 cm will not cause to much confusion ( =16 feet )

Ben

[John E Hardiman]

3/8":12" = 1:32, 3/4":12: = 1:16

I think you meant 3/100 and 6/100?

I have no idea what "standard" is in metric modeling, probably 4/100, 5/100 or 10/100. Somehow 31.15/1000 doesn't seem "natural".


No, I meant a drawing done in 3/8":1' could be scaled with a 1:32 scale, i.e. 1 measured unit = 32 full sized units. Such metric scales are made, but are rare.

Normal metric scaling follows standard drafting practice then increases by a factor of 10.

1/2
1/3
1/4
1/10
1/20
1/30
1/40
1/100
1/1000

[Don Kurylko]

Just to expand a bit on John's post, commonly used Metric scales are:

1:50 - approximately equal to 1/4" = 1’-0”
1:25 - very close to 1/2” = 1’-0”
1:15 - very close to 3/4" = 1’-0”
1:10 - 20% larger than 1” = 1’-0”
1:2 - half size

[Stiletto]

Bennieboat, all building trade work in NZ is done in metric. We dont use centimeters, they are for dressmakers.

Your example of 91.4cm would be expressed as 914 (mm) on the job and perhaps .914 on plans.

Mark, 1:30 looks pretty close to what you use now , it would be much the same size on the sheet, will you do a direct conversion of your original measurements to millimeters?

[Ken Hutchins]

Why convert to metric? Another possibility to make life easier is to convert the fractions to decimals.

[Mark Van]

Since I used a CAD program, it is not very difficult to change the measurment from feet to meters, all I have to do is re-size the drawing. My other design I just kept the drawings the same size and used 1/48 and 1/24 scale, which I think is awkward. It looks like 1:30 and 1:15 are the closest to the drawings that I have.

[boylesboats]

Damn, stop it.....:confused: .. ... My tape measure I just brought, drives me nuts, Metric on one side, S.A.E on the other....
Measuring metric is fine... As far as scaling as in drawing on the drafting table, forget it.....:confused:

[Mark Van]

I just looked up drafting supplies to see what metric scales were available (why didn't I think of that first?) It appears that 1:15 is not available in standard scales, but 1:30 is. Perhaps I could use 1:20 for most of the drawings. I will have to experiment to find out what will neatly fit on the page.

[Graeme Forrest]

The metric boat plans I have seen and used are usually;
1/1
1/2
1/5
1/10
1/20
depending on the size and detail required.
All of the above are used in the Golant Gaffer drawings. 1/10 for the main construction plans, sailplan is 1/20,spars 1/20 and 1/5 for sections,1/1,1/2, and 1/5 for constructional detail sheets.
All dimensions are millimetres, for example, mast is shown as 6700 overall with the hounds at 5500.
Graeme

[PeterSibley]

1:20 would be good .

[LeoinSA]

I just looked up drafting supplies to see what metric scales were available (why didn't I think of that first?) It appears that 1:15 is not available in standard scales, but 1:30 is. Perhaps I could use 1:20 for most of the drawings. I will have to experiment to find out what will neatly fit on the page.

Mark,

Speaking just for myself, I find it easier to draw using CAD at full scale - either metric or English - and put a built in scale on the drawing itself.

Doing that makes the drawing independent of the paper size it is printed on.

An example would be a 9000mm long x 3000mm beam design. If there were a scale on each drawing that specified 1000mm and this built-in scale had 5mm lines for the first 100mm and then 25, 50 and 100mm lines thereafter, the drawing could be printed on an letter size 8.5x11 paper or a D size at 24"x36" and the measured scale would be the same as originally plotted on the CAD program.

Caveat - assuming that the printer prints 100% of the field and does not shrink it to allow for unprintable margins. But even if the printer 'cheats' by a couple of percent, the drawing would still be scalable without resorting to external arbitrary scale tools.

Hope this helps.

Leo

[Mark Van]

I do the drawings at full-scale with the CAD program, I just think that it is convenient to be able to use a standard architect scale when using the plans. I am limited to 8 1/2" to 14" drawing size because I don't have a large scale printer. I printed a scale on the Mark V 39 metric plans, because they were not printed to a convenient scale.

[John Gardner]

Yes, you can get metric scales.

http://www.forestry-suppliers.com/product_pages/view_catalog_page.asp?id=5937

But if the plans are already scaled in english measurement....why bother to convert? :confused: Just asking for trouble IMHO.

Unless you are look to find a metric scale for direct reading. Then..

3/8" = 1' converts to 3/8 = 96/8 ==> 1:32

3/4 = 1' converts to 3/4 = 48/4 ==> 1:16

Neither of these is a standard metric reduction. See ANSI Y14.100 (ex. Mil-Std -100) I believe.
Looking for a 2" to 1' scale.

[Hans Friedel]

Always use millimiters

Practical scales are 1:1, 1:2, 1:5, 1:10, and maybee 1:20

The scale depends on the frames A4, A3, A2, A1 and A0. The A2 and A1 are nice ones for boats

Hans