Bookcrafters who have seen a Jenner Book ~ or looked at the illustrations [127242] ~ may well feel they could make a similar book. I assure them ~ they can! If you are thinking about it ~ here are some notes to help you on your way.
Select your papers with care. There is no point in spending time on a book if the paper is not suitable for the intended purpose. Show-through is a common complaint. Wrong surface is another. If buying a book you have to have what is on sale ~ if making it you can choose! Conversely ~ I once spent so much time on a rather super notebook that I could not bear to spoil it by writing in it! Bookcrafts often presents the challenge of choosing the best course ~ or at time the middle route.
Arrange for the paper to be short grain if you can. When given a choice the better option is invariably to crease with the grain ~ it leads to better opening or layflat. Cheap papers are usually only available in smaller formats and are invariably long grain ~ so your selection is limited. You can only make an A6 book from A4 sheets if the folding is to follow the grain. Art suppliers stock suitable papers, and in larger sizes. There is no hard and fast rule about the grain of larger sheets. One supplier I knew sold A2 and A4 as long grain ~ and they prominently advised that A3 was short grain. For some cartraidge papers it is difficult to tell which way the grain runs ~ so that is unimportant. There is no problem with handmade papers ~ they do not have grain.
Remember the hinges of the Jenner Book are only threads. Although they can be replaced it takes time. The size and extent of your book may put quite a strain on the threads ~ maybe keep the book at A5 or less perhaps?
The Jenner Book sewing technique is similar to Coptic Sewing in that the threads remain visible and do all the work of the hinges ~ but in other respects it is quite different. Coptic sewing uses one continuous thread ~ not counting the joins that are usually necessary. Jenner sewing uses a separate thread for each section and a second thread for joining covers and sections and forming the book.
Each section is sewn using the single section sewing technique ~ out ~ in ~ out ~ in ~ out ~ reverse ~ in ~ out ~ in ~ skip one ~ out ~ and so on ~ and reverse ~ and so on ~ and ~ in ~ tie-off. There are quite a few holes and so stitches. Probably twice as many as traditional bindings would use. I chose to do this to provide more strength and wearability to the all-important hinge threads by sharing the workload.
The covers are also sewn using the ins and outs as above ~ except that after every 'out' the thread is criss-crossed across thethreads of each hole of each section until the 'in' bit takes place on the opposite cover. With equally spaced holes this continues to one end at which stage the criss-crossing breaks down and one thread ends up being rather loosely locked in. To tighten the appearance of this I have made a tiny 'extra' hole at each end to keep the single thread neatly housed in a small gap.
The proximity of the two end holes is a wek pont. With good quality cover boards it does not matter. WIth thinner boards there may need to be some invisible stregthening ~ a guard of Japanese paper ~ or a narow strip (6 or 8mm) of old hankerchief would do well. Paste it right down the whole internal fold of the cover.
As with all bookbinding sewing it is important to keep the tensions even throughout. They do not need to be too tight ~ the threads will move around more easily if more relaxed than woud be the norm.