I modified a moustache/sideburn trimmer that I bought at Wally-World, I carefully reground the top edge/angle of the upper blade and the bottom edge/angle of the bottom blade. This brought the blades to a point rather than the rounded/smooth edge that won't cut skin when used for personal grooming. With the sharp edge you can "erase" all stitching, be sure to do it from the back and don't go thru the backing, the top stitches will brush right away.
This is the reason that these trimmers for embroidery are more expensive, they are made for grooming then they are modified, tested and repackaged for their new function. Doing this add more work to the final product.
