How to adjust the tightness of sewing machine bottom thread and top thread?

Check whether the bottom thread is correct first, and then check whether the thread clamping spring and shuttle spring are properly adjusted. Whether the machine lubrication is normal. Whether the needle bar height is normal. Whether the position of hanging shuttle matches the height of needle bar. Whether the surfaces of hook and shuttle sleeve are smooth. If these problems have been eliminated, please check the distributor again. If there is no problem, it is the performance problem of the machine itself. If some woven fabrics are too thin or too thick, it is difficult to adjust the bottom line.

Extended data:

General sewing machine consists of four parts: head, frame, transmission and accessories.

The nose is the main part of sewing machine. It consists of four mechanisms: piercing, hooking, picking and feeding, and auxiliary mechanisms such as winding, pressing and tooth dropping. All mechanisms work in a reasonable and coordinated way, working in cycles, and sewing materials.

The frame is divided into two forms: bed board and chassis. The bed plate of the bed plate frame plays the role of supporting the machine head and is used as a workbench during sewing operation. There are many styles of bed boards, including one or more bucket folding, cabinet type, desktop type and so on. The chassis of the chassis frame plays the role of supporting and storing the machine head, which makes the sewing machine easy to carry and keep.

The transmission part of sewing machine consists of frame, hand crank or motor. The frame is the pillar of the machine, supporting the base and pedals. When in use, the operator steps on the pedal to drive the pulley to rotate through the crank, and then drives the machine head to rotate through the belt. Most hand cranks or motors are directly mounted on the nose.

Accessories of sewing machine include needles, spools, screwdrivers, oil pots, etc.