Brother International T-8752C Instruction Manual - English - Page 76

13. STANDARD ADJUSTMENT 13-4. Clearance between rotary hook and needle plate The clearance (A) between the rotary hook (1) and the needle plate (2) is adjusted as follows at the time of shipment from the factory. Model Without thread trimming T-8421C With thread trimming T-8422C T-8722C T-8452C T-8752C Distance (A) 0.9 - 1.2 mm 1.4 - 1.7 mm 3054M 3055M • Check clearance (A) each time parts such as the rotary hook (1) and the needle plate (2) that affect clearance (A) are replaced. • To adjust clearance (A), replace the thrust ring (4) that is in between the rotary hook (1) and the rotary hook base (3). • Three types of thrust ring (4) are available. Measure the thickness of the thrust ring (4) that is currently being used, and replace it with a thrust ring (4) of the appropriate width. Part code SA4444-001 SA4038-001 S09260-001 Thickness 0.8 mm 1.0 mm 1.2 mm • When replacing the rotary hook (1), loosen the three set screws (5). Be careful not to lose the thrust ring (4) at this time. Touching gently NOTE: There is a piece of felt (7) for lubrication at the base of the rotary hook shaft (6). Gently press down on the rotary hook (1) when tightening the set screws (5) so that the rotary hook (1) does not lift up. If the clearance is too large • The inner rotary hook may come out from the needle plate (2). If the clearance is too small • Poor thread tightening may occur. • Lower thread trimming errors may occur (models with thread trimmer). • The right upper thread may be cut too short (models with thread trimmer). * These problems may occur particularly if the stitch length is large or when carrying out thread trimming during chaining-off. 3056M 67 T-8421C, 8422C, 8452C, 8722C, 8752C