When I bought my Brother 836 from my partner's mother, it came with a colour changer, ribber and knit-leader. Once I'd got back up to speed with using the machine, and mastered the ribber, I turned to the knitleader (also known as knitradar or knit contour with other brands - it's the same thing). The knitleader is an ingenious device, being basically a roller that feeds a mylar sheet, on which is marked the outline of your garment. This is one of those occasions when machine knitting really comes into its own. You create a tension swatch of 40sts x 60r that you are happy with, in terms of feel and density. You measure it, and use these measurements to set the row feed in cms and mms, and to select a stitch scale, which are cardboard rulers that come with the knitleader. Then you draw half of your garment and half the sleeve along the centreline of the mylar sheet. You can draw the back and the front on top of each other. Some knitleaders require a half or quarter scale pattern - consult your manual.
Now, wind the mylar sheet into the knitleader, set up the first row, and cast on the number of needles it indicates. This device is perfect if you've got a vintage pattern but have no hope of ever getting the correct yarn. Conversely, if you have a yarn you want to use, and a pattern you like, but it's written for a different yarn thickness, the knitleader will banish that problem, and certainly banish the need for calculators and spreadsheets!
Another use of the knitleader is to draw out an intarsia design on it. Then instead of having to keep referring to your graph, and possibly making a mistake, you just select the colours the knit leader is showing you on that line. Easy!
I don't understand why they're not far more popular. I'm going to have a go at designing some garments later on this year, and the knitleader is probably how I shall work out the pattern so that I can write it out longhand.
I have the KL116, which fits both standard and chunky Brother machines, and the KR7, which was bought specifically to go with the Silver Reed - not been out of its box yet.
Hand-knitting progress - back of baby cardi completed, now onto left front. Go me!
<does silly dance>