Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[KEMO]

Hiya,
        I have a set of trawler plans drawn at 1/50. By what percentage would they have to be enlarged to make them 1/32.

Keith.

[craggle]

I think you take the scale you have and divide it by the scale you need then multiply by 100.


So 50/32 = 1.5625 x 100 = 156.25%


This website seems to confirm that.
http://www.ipmsstockholm.org/magazine/2003/05/stuff_eng_tech_scaling_drawings.htm


Craig.

[dougal99]

Craig is. of course, correct. One way to remember what to do is realise that if the scale is 1/x then you need to multiply by 'x' to get full size. Then to get the scale 1/n you have to divide full size by 'n'. Thus in one step you multiply by n/x.


HTH

[KEMO]

Hiya,
        thank you for that, I knew there had to be a simple formula somewhere.

Keith.

[steamboatmodel]

Just make sure that the copy machine is copying at the ratio it is claiming it is. Some are out by as much as 10%. I usualy add a scale to the drawing if there is not one already, or make two marks ot a spaceing that will come out to a measureable spaceing.
Regards,
Gerald.

[derekwarner]

This is a very good idea Gerald..........better still...add both a horizontal and vertical reference

So using the ratio offered by Craig....draw a 100 mm long vertical and a 100 mm long vertical line on the plans

Naturally ....post enlargement, both lines should measure 156.xx mm  long

I have experienced commercial copy enlargers [@ BHP steel] where the enlargement component % varied between both ......axis  ....Derek

[Sandy]

Sometimes you also seem to get what I call 'roller skid'.

If a smaller drawing being enlarged has to go through twice to give separate elevation and plan sheets due to the size of the enlargement, you can find that lengths of the ships on each set is different.

Very puzzling. And vexing.

[grendel]

there can be up to 1% difference in the length shown on a drawing just between a wet and dry day, add to that a similar amount for printing 'stretch' and that easily accounts for 20mm on a 1m plan length, if you are scaling at a copy shop or anywhere else take a known measurement from the original plan (as this too may not be accurate) draw your line and expect to have a couple of goes to get the exact scale right (a good print shop might allow these free but you may need to pay)
Grendel