Rotary Hook (Rh), Cutting Blade And Hook Drive Belt In Artista 640 - Fritz Gegauf Bernina artista 630 Service Manual

4.21 Rotary hook (RH), cutting blade and
hook drive belt in artista 640
Disassembly:
1. Remove back cover.
2. Remove stitch plate.
3. Loosen screw (2) and bobbin case retainer (1).
4. Remove belt tension screw (3).
5. Remove tensioner, disassemble, then clean and oil
idler pulley shaft.
6. Remove flat headed screw (7).
7. Pull hook out to the front.
8. Slide drive belt out and remove.
9. Remove two cutting blade screws.
10. Replace cutting blade.
11. Check hook for smooth operation, clean and lubricate,
12. Remove any burr from hook tip, hook body and retainer
Assembly:
1. Position new cutting blade and tighten the two screws.
2. Slide drive belt in.
3. Slide hook into drive belt from the front, and tighten flat headed screw (7).
4. Refit belt tensioner and tighten drive belt (is tightened automatically by spring motion). Tighten
screw (3) and check ease of run.
5. Refit and set bobbin case retainer (p. 49).
6. Check hook setting. Adjust if necessary (p. 52 -).
7. Refit covers.
8. Carry out a functional check.
9. Sew-off.
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