This is a tool that every quilter must own if she wants to have good tension on her quilts. Ã‚Â The TOWA gauge should be used to adjust your bobbin case to 170-240 for all Gammill models except Premier 18" throat machines which require 200-300. Just load your bobbin case with bobbin, pull the thread thru the gauge, and note the number. Ã‚Â Turn the tiny tension screw on your bobbin case and re-test again. Ã‚Â Keep adjusting until you get "200" and the needle is smooth and not bouncing. Ã‚Â Now, load that bobbin case into the machine and adjust your UPPER tension tighter and tighter while sewing on scrap quilt until bobbin threads start to appear on TOP. Ã‚Â As soon as the bobbin thread starts pulling up, loosen the top a whisker until the bobbin thread isn't pulling up anymore. Ã‚Â SHAZAM! You now have perfect tension. Ã‚Â No more train tracks, eye lashes, or pokies (assumes no mechanical issues with the machine). Order your TOWA gauge today! Ã‚Â And don't forget to quickly check EVERY SINGLE BOBBIN before loading it into the machine. Ã‚Â An ounce of prevention is worth a pound of frogging.