Hi if you are looking for an article that explains how can you time the hook of your juki buttonhole machine then you are at the right place. Here I have explained the complete method of timing the hook, so let's get started: The best timing of the needle with the sewing hook is when the needle stitches right in the center of the needle hole of the needle plate. When the needle has begun to rise from its lowest point and the point of the hook point is timed with the center of the needle, the space between the upper part of the needle eye and die hook point is 1.6~l.8 mm  ( B). 
juki 761 lbh hook timings , juki 781 lbh hook timings , juki buttonhole hook timings
Juki 761 lbh japan juki 781 lbh japan hook timings

For jerseys and knit goods, 1.6mm (l/16"i space is better. For correct timing adjustment, use the timing gauge of fig (A).  Rotate the driving pulley in the regular direction, and when the needle has begun to rise up from the lowest point, insert the 2 part of timing gauge between the needle bar and the needle plate and with the needle bar contacting the gauge, time the point of the hook with the center of the needle. The clearance between the needle and the hook point is about 0.05mm but when the needle is swung from right to left, or vice-versa, be sure that they don't touch each other. 


juki 761 lbh japan hook timings , juki 781 lbh japan hook timings , buttonhole hook timings
Juki 761 lbh japan | Juki 781 lbh japan hook timings