How to work out size of Gusset?

[Ski]

Hi All,

I hope you can help me.  Is there a formula, or a process in which to calculate how big a gusset should be?  When I attempt a bag Im always left with extra/less length which ruins the process.  

Please see an example picture from the internet, followed by an even more complicated example from De Bruir.   If the bag is one long leather all the way around with a zipper, how does one calculate or work out the size of the other bit (gusset?).  Is there a trick?

[chrisash]

Make a thick card template and fit together with sellotape or pins and adjust to fit and when happy take apart and use a template for cutting the leather, dont forget to make allowances for seams  etc

[kiwican]

Diameter  x 3.14

Edited December 22, 2018 by kiwican

[Aven]

1 hour ago, kiwican said:

Diameter  x 3.14

That works for round ends.  The top one is D shaped and the bottom one is more of a rectangle with rounded corners.

Chrisash has the right approach, if you aren't playing with a CAD software, then mocking it up with cardstock, chipboard, something is your next best route.

[Handstitched]

I do something similar to chrisash . I use brown paper, news paper etc. using pins , paper clips/clamps  UHU glue  or what ever  to make a gusset /pattern  . Once I'm happy with the size shape etc. then I  cut out the leather pieces. It my take a lot fiddling around  as you're forever making adjustments to the  paper template. But  the upside to it , you may only have to do it once  and can use it to make many projects . If I know I'm going to make a run of the same thing, then a MDF, or hard template may be considered. 

HS 

Edited December 23, 2018 by Handstitched

[Ski]

Thank you all, I will give it a go.