Accounting for fold in the spine of book/notebook covers - help

[RoperDKC]

I'm not sure how to even word it, but here it goes. 

 

When making a tallybook/notebook/legal pad cover etc., I get it cut out and finished up and even though I have excess leather on both sides past where the book sits, when I insert the book and close it to use as the cover was intended to be it won't fold right and it's like I didn't cut it wide enough. 

 

So, what should I do to account for the fold? How much extra should I give myself? Is there a general "rule of thumb" you more experienced guys use? 

 

More generally- Layout and design wise- what's the process you use for doing any kind of book cover?

 

Any help or insight is much appreciated!

-Roper

[JLSleather]

"Generally speaking"... http://www.jlsleather.com/diy/pattern-making/leather-pattern-notebook-layout/

 

[RockyAussie]

Get a piece of leather the same thickness/substance about 1" wide and bring it over about 1/4" or more if the cover board is very thick, at the front and over the spine and mark it about 1/4" past on the back side. This gives you a leather ruller which just remember not to pull to tightly when going around. Alow similiar on the top and bottom and stitch in about 2.5 to 3mm in. Thats the best way I've found.