How to Deal with Excessive Noise in a Lockstitch Sewing Machine?

Sep 07, 2023

PART 1

The uneven meshing of the umbrella gears can cause noise when the Lockstitch Sewing Machine's gears rotate at high speed.

Solution:

Loosen the fastening screws of the umbrella gears with uneven meshing. Tap the correct meshing height on the gears by loosening the screws on the sleeves that come into contact with the umbrella gear shaft. Then, tighten the fastening screws on both the umbrella gear and the sleeves separately.

PART 2

Noise is caused by axial looseness in the upper, vertical, and lower shafts.

Solution:

Loosen the two fastening screws of the sewing machine gears, then readjust the axial clearances of the vertical, upper, and lower shafts.

PART 3

Noise issues due to excessive or insufficient meshing clearances in the umbrella gears.

Solution:

Correct the meshing clearances of the umbrella gears by tapping the sleeves. Typically, the meshing clearance between a pair of gears should be between 0.20mm to 0.40mm.

PART 4

Poor quality gears or excessive dirt.

Solution:

Apply a small amount of abrasive paste on the meshing surfaces of two gear pairs, then manually rotate the upper wheel in both directions for approximately 10 to 15 minutes. Clean the dirt with kerosene, lightly apply lubricating oil, and then adjust the clearances as required.