On my NN5 there is a two-position metal slide control that is designed to let you 'feel' 15 degree angles. This no longer offers the 'feeling' so I have to look very carefully at the dial. This is not easy to read even with my glasses! It looks like it works due to indents on a washer but perhaps they have worn out? Is there a way I can get the feeling back so that I know when I am exactly at 0 and 90 degrees?