Brother International CB3-B917 Service Manual - Page 41

5.ADJUSTMENT 5. ADJUSTMENT CAUTION Assembly and adjustment of the sewing machine should only be carried out by a qualified technician. Turn off the power switch at the following times, otherwise the machine may operate if the pedal is depressed by mistake, which could result in injury. * The motor will keep turning even after the power is switched off as a result of the motor's inertia. Wait until the motor stops fully before starting work. • When carrying out inspection, adjustment and maintenance • When replacing consumable parts such as the loopers and knife. If the power switch needs to be left on when carrying out some adjustment, be extremely careful to observe all safety precautions. Be sure to wear protective goggles and gloves when handling the lubricating oil and grease, so that they do not get into your eyes or onto your skin, otherwise inflammation can result. Furthermore, do not drink the oil or eat the grease under any circumstances, as they can cause vomiting and diarrhoea. Keep the oil out of the reach of children. Use only the proper replacement parts as specified by Brother. If any safety devices have been removed, be absolutely sure to re-install them to their original positions and check that they operate correctly before using the machine. Any problems in machine operation which result from unauthorized modifications to the machine will not be covered by the warranty. 5-1.Needle bar height 5-2.Loop spreader Loop spreader Loop spreader Needle bar lowest position Needle bar TQx1 TQx7 307s Needle 320s 319s Looper spreader groove cam 0.3 - 0.5 mm With the needle bar at the lowest position, align the reference line of the needle bar with the lower edge of the needle bar metal. Move the needle to its lowest position by rotating the pulley. When the loop spreader has been advanced to its closest point to you by turning the looper spreader groove cam, adjust the clearance between the needle to 0.3 - 0.5 mm by moving the loop spreader groove cam backward and forward. 5-3.Point where needle and looper meet 5-4.Clearance between needle bar and looper Needle bar 324s TQx1 TQx7 501s Looper spreader groove looper Looper settincgam shaft Raise the needle bar from the lowest position until it is aligned with the needle bar metal. Adjust the tip of the looper so that it is at the center of the needle by using the Looper setting shaft. * Set the delta cam lightly against the looper spreader groove cam. 5-5.Needle guard 0.03 - 0.08 mm 326s Screw looper When the tip of the looper is aligned with the center of the needle, the clearance between the looper and the needle should be 0.03 - 0.08 mm. 5-6.Fixed knife Needle guard Fixed knife 329s 0.1 - 0.2 mm Approx. 2 mm 331s The clearance between the needle and the needle guard The distance between the blade edge of the fixed knife and should be 0.1 - 0.2 mm. the center of the needle should be approximately 2 mm. 35 CB3-B916A/B917A