The Solution for Skipped Stitch
Durning the machine sewing, sometime it will have the skipped stitch, please check the solution as below:

Attention: please shut down the power to prevent accident

1、The correct way for threading 
Example model: H5-5T 

Complete Graph

Step Diagram

2、 Checking the needle point whether bend or burr
With the long high speed working, the needle point will become blunt, even bent. The distance between the needle point and hook becomes large, hook point can't hooking the thread, then the machine will have skipped stitch. 

3、The right position between the hook and the needle. 
Turn the hand wheel, make sure the needle position is in 2.2-2.5mm  (from the bottom to up),  adjust the needle position within 1-1.1mm(above needle hole). Then adjust the distacne with 0.05-0.1mm between the needle and hook.

4、Adjust the presser foot
Loose the presser foot nut, adjust the presure to fit the presser foot, clockwise is heavy, anticlockwise is light, the right postion is 29-32mm