How to "ZERO-OUT" Singer Models 401A and 500A Sewing Machines

Follow this tutorial for setting the width of the zigzag system. Formally called "setting the bight amplitude stop plates" or Zero-Out. If your zigzag width is too narrow or too wide this testing and resetting will fix that. Easy to do with just a screwdriver. Do it yourself instructions you can follow. MUSIC: Hero's Ascent by Chris Haugen How to set the zigzag width singer 401A, Singer 500A