Advice for Math-Challenged?

[Haellyn]

I'd like to design my own laptop bag and have a vague idea of what it should end up looking like, but I'm incredibly bad at math, even if it's double- or triple-checked, so things end up too small or crooked. Happily all I've wasted so far are paper bags and scrap leather. Anyone have any tips that might help?

[robs456]

9 hours ago, Haellyn said:

I'd like to design my own laptop bag and have a vague idea of what it should end up looking like, but I'm incredibly bad at math, even if it's double- or triple-checked, so things end up too small or crooked. Happily all I've wasted so far are paper bags and scrap leather. Anyone have any tips that might help?

As you want to design it yourself, buying a pattern is not the solution. Even if that would be the simple way out...
So you need to draw what you want then prototype like mad.
I recommend using cardboard the same thickness as your leather and either cutting off or taping on pieces until you have what you need. Then use that as a template on your leather.

 

[kirbytorres]

I use felt cloth with roughly the same thickness of the leather to create the prototype and then use that as your pattern for the leather

[Stetson912]

I have used 6mm craft foam to do mock ups. Design a pattern and cut it from foam to see how it all fits. You can use contact cement as usual to glue it up. 

You can also take a long strap of leather the thickness you will use and wrap it around the object you are making the case for. I would wrap the strap around the lap top and overlap it on itself 1/4 to 1/2" to allow for stitching. You can eyeball that and then just write down the length you get from measuring the strap 

[Haellyn]

Thanks for the suggestions, everyone. Much appreciated! I'll try a couple things and see how it turns out.

[zipsfan]

Just switch to metric, in this case MM (millimeter), and use it exclusively. Everything is base 10 and can be converted regardless of item size.