Someone asked about how to read 'historical' drafts. After mulling it over for a while, I felt a more extensive approach to answering this question might be useful. So I'm going to go through my personal library and talk about some of my books, how the authors approach presenting technical information and at some point will also discuss the different mechanics of the most common looms available today.
I'm beginning with M. P. Davison's book because so many people have it in their libraries.
It was first published in 1950, was updated many times and Davison's family still retains the rights and continue to publish it (or so I understand). As such it spans a rather large chunk of 'modern' hand weaving time.
While there are other similar collections of drafts, this one seems to have stood the test of time.
But. How many of you have read the beginning pages? When dealing with a book informing technology, it is always a good idea to read the beginning bits.
For example, how many people get the book, flip it open to a design they like, put a warp on their loom and then can't understand why their cloth doesn't look like the photo in the book?
Only to discover that the book is written for sinking shed looms and theirs isn't.
I have seen more than one person then come to the conclusion that they might as well give the book away because they don't have a counter balanced loom.
Thing is, drafts can be read appropriately for the type of equipment one has.
In terms of using a draft written for counter balanced looms on a rising/jack type loom? Just keep weaving and when you cut the cloth from the loom, turn it over. Voila. (I frequently weave cloth 'upside down' in order to lift the fewest number of shafts.)
OR, amend the tie up to tie the blanks instead of the Xs and bob's your uncle.
Davison also explains how to read the treadling and the notation she has used, right there on pages xi and xii, so all the guess work and teeth gnashing could be avoided if people would just read the introductory pages of *any* technology book.
A draft is a graphic representation of what the threads are supposed to be doing, first in the threading, then the tie up and then the treadling. The area where the photos are would more usually be the drawdown, but having a photo of the cloth is helpful. Davison has approached the book by using the same two yarns, one colour in the warp, the other in the weft, so that the path of the yarns through the weave structure can more easily be seen. This is not a 'design a pretty cloth' book so much as it is 'let's see how weave structure can work to create a design or texture'. She then leaves it up to the weaver to add colour to personalize their cloth.
How the four parts of the draft are arranged is not set in stone although in the 21st century in North America it has become the convention to have the threading at the top, the tie up box to the right hand side with the treadling below it.
In other countries, they do draw ups, which makes a lot more sense because we weave the cloth 'up'.
As for the tie up box being always to the right? Davison has the box on the left on the odd numbered pages and the right on the even numbered pages. This does not change the meaning of the information.
New weavers will sometimes assume that the only 'proper' tie up is the 'standard' 2:2 twill. Watch the tie up boxes carefully, because sometimes Davison will change the tie up part way down the page.
If you don't have computer software (or even if you do), sometimes it is a good idea to hand draw the draw downs, just to make sure you know how they work. I am old enough that I started weaving long before computers were available for personal use and I have drawn many a draft by hand. Still do when I'm working out a block motif in many cases.
So, generally the threading tells the order the threads are to be entered into the heddles (which shaft they are on), the tie up box tells how the treadles are to be arranged/tied to the shafts, and the treadling sequence the order the treadles are to be used.
How each author conveys that information may vary in terms of the symbols used and the type of notation they present. Reading the beginning pages will usually reveal how the reader is to do that.