I got lost at Google Books again. Google Books has some wonderful offerings of antique books. There's a book called The Workwoman's Guide which has some great diagrams for making clothing in 1840 toward the end of the book. You can download a PDF of the book. The diagram above is from that book.
There's a wealth of information on the web about making bonnets. The problem is you have to wade through lots of spammy and harmful sites to find them. I spent some time finding some resources for you.
Buns and Baskets has a site focused on "How to Dress Like a Pioneer." She has some yummy tutorials and patterns:
If you are into Regency styles, there are some interesting video tutorials at the Oregon Regency Society's site for making bonnets.
Here is a video tutorial for making a Regency bonnet that has no words whatsoever. Enjoy!
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