I recently bought a Singer 127 Sphinx treadle at a yard sale. It was very gummed up, so I got her all cleaned up, oiled, etc. It ran great and the stitch was very even. Yesterday I tried to make the stitch a little shorter and after messing with the stitch length screw and the upper tension I have made a mess of it! Now my stitches are long and super loose. The instruction book tells you all kinds of things about taking the tension plate off and measuring from the eye of the needle, etc. etc. I can't believe I messed with it - it probably just has one stitch and that's it. I keep trying and can't get it back to the original stitch - any ideas or should I take it to a shop?