1.Remove the bobbin and bobbin case.
2.Remove the needle plate and the feed dogs (usually involves removing a couple of screws). Put the parts in a safe place such as a small container or cup.
3. Using the hand-wheel take the needle down to it's lowest point. Now raise the needle/needle bar 2millimeters. You can use the thick part of a needle shank as a gauge for this.
4. Look and check that the tip of the bobbin hook is centred with the shaft of the needle. If it isn't look for two or three screws attaching the collar of the drive hook to the drive shaft. Gently move the hook so it's tip is centred with the needle shaft, taking care not to move the drive shaft. (Hold the handwheel firmly with your right hand while trying to loosen and move the hook).
5. Now check the clearance between the hook tip and the back of the needle using a piece of note paper as a guage. If the paper can be inserted between the hook tip and the back of the needle and there is a slight drag when you move the paper back and forth then the clearance is fine. If the paper slips very easily between the hook tip and the needle then you have too much clearance. If the paper won't slide or the needle slightly deflects when you insert the paper then there is not enough clearance. Adjust the hook tip clearance as above, again taking care not to turn the drive shaft.
Note:If you do move the drive shaft go back to step 3 and continue as before.
6. When the above adjustments have been made GENTLY but firmly tighten up the small screws attaching the hook collar to the drive shaft. The hook tip should be between 1 to 2mm above the eye of the needle at this point. If it isn't you'll have to loosen a screw on the needle bar and gently adjust the needle bar height so that the eye of the needle is below the tip of the hook by 1 to 2mm.
7. When all the above adjustments have been made replace the feed dogs, needle plate, bobbin case and bobbin. Thread up your machine and 'test sew' on a scrap of material using the hand wheel to move the needle up and down. If it all checks out OK, with no unusual noises or the needle hitting something soldid then sew using the machine's foot pedal as normal.
Note: It's not very difficult to do and becomes second nature after two or three attempts. Just take it slowly and take care not to overtighten the screws. Sometimes, depending on the brand and model of the machine, it's not necessary to remove the feed dogs to get a clear view and access to the screws on the driveshaft.
Regards,
Allan Wells
Allan Wells, May 2010
