Blind hemming is never an easy technique and demands practice and patience. It is possible to sue your overlocker to blind hem and the blind stitch foot is equipped with a guide to help keep your stitching straight. 

Janome 
103, 1110DX, 134D, 203, 204D, 234, 234D, 303, 304D, 334, 334D, 3434D, 434D, 434DR, 504D, 534D, 6234XL, 634D, 644D, 7034D Magnolia, 734D, 744D, 7933, 8002D, 9002D, 9102D, 9200D, HF3434D, HF504D, HF9102D, HF7933