Hello,
I am slowly accumulating things for a project and have a question about scale drawings. I am going to attempt build a Japanese CV in 1/350 scale. most of my drawings are 1/400 or 1/200 scale. How do I shrink or enlarge them to 1/350 scale ?? Thanks in advance.

Hi Phil, someone ought to check my math but using a good photocopier (if any Copy-shops are still open) you could enlarge/reduce as follows;

Reduce the 1/200 drawings by 57.14% and Enlarge the 1/400 drawings by 112.5%

If you can’t change the plan sizes anywhere I guess you’ll just have to use those conversion figures for each part you make! Mind-bending & if I’m wrong it only goes to show I’m no engineer, but at least I tried!

Tim, your numbers are spot on but the wording should be reduce to and enlarge to (rather than by).

Pedantic, I know, but the results are very different!

Cheers, D

Thanks Damo! I’m quite shocked actually, so now I’m good to do a scale model of the Tacoma Narrows bridge right?! Yep you're right I began to think I should have said “to” after I posted but I was too exhausted to log back in until I’d had a nap

Fair call Tim, you can't rush these things and naps are important. I should have realised that's where you were and left it a bit longer before I commented

Thanks for the help...have a nap and a beer on me

if this helps....

https://drive.google.com/file/d/1ZWbd5zPMO1U5A4cpeLnBvvpjePw7A50P/view?usp=sharing

Hey,
Thanks a lot I had this along time ago in a magazine article and it disappeared over time and my many moves. I is now saved on my computer.

My favourite tool is Frank Krenshaws Scale Calc

Easy to use, you can go from known to known scales (1:96 to 1:35, etc) or from known length on drawing, to desired output length, Metric, Imperial or mixed! it will give you the %age enlargement needed.

The above takes the whaa??? out of it for those of us mathematecally challenged.