Holes in Fabric/Needle Tears
1) Replace Needle Loosen the nut two turns. Remove the old Needle and replace it with a new Needle. Set the new Needle all the way back against the Stop Pin, and retighten the nut.
2) Incorrect Needle
A) Try a smaller Needle. Needles are available in sizes from #000 to #8. The larger the number the bigger the Needle.
B) Try a Ball Point Needle. Merrows designation for Ball Point is F.
Ragged Edge (Fabric looks chopped, not cut)
1) Check Cutter Sharpness Place a single strand of thread between the two blades. Turn the Handwheel by hand, and see if the thread is cut cleanly. If the thread is not cut cleanly, adjust, sharpen, or replace the cutters.
Poor Coverage on Edge
1) Increase the Stitch Count Increase the number of stitches per inch by replacing the Feed Eccentrics (stitch cams). Use Eccentrics with a higher number. The number on the Stitch Cam represents the approximate number of stitches per inch.
2) Use Additional Thread
A) Use a heavier thread as the coverage thread.
B) On certain styles it is common to use more than one Cover Thread. 2DNR-1 and 3U are examples of this approach.
1) Check the Threading Refer to the Threading Diagram provided with the machine, and ensure that the threading is proper.
2) Increase Tension of Thread Turning the Tension Adjustment Nut clockwise to increase the tension. The standard setting is considered to be lock nuts on all tensions approximately even with the ends of the Tension Studs.
Edge Curling with Stitch Too much fabric in stitch
1) Decrease Tension of Thread Determine which thread is breaking, and decrease the tension on that thread. Turning the Tension Adjustment Nut counterclockwise decreases the tensions. The standard setting is considered to be lock nuts on all tensions approximately even with the ends of the Tension Studs.
2) Adjust Cutters Move the Cutters to the left to reduce the amount of fabric in the stitch.
Scratch on Fabric Feed Dog Tracking on Fabric
1) Check for Burrs/Sharp Edges
A) Check the Feed Dogs, and remove any burrs encountered.
B) Check for sharp edges on the Feed Dog slot(s) of the Needle Plate. Buff the sharp edges until smooth.
2) Too Much Presser Foot Pressure Loosen the Lock Screw, and turn the Adjustment Screw counterclockwise a few turns. Retighten the Lock Screw.
3) Feed Dogs Set too High The Feed Dogs should be set so that the bottom point of the Feed Dog tooth is even with the top of the Needle Plate when the Feed Dogs are at their highest point of travel.
4) Wrong Feed Dogs
A) Fine Tooth Feeds should be used with light fabric.
B) Urethane Feeds should be used with delicate fabric.