Radial Saw Problem

I created and linked a forum post to this page in 2003 when trying to solve the problem described.  The problem has recurred so I had to dig up these two pages.

After reading this page you can go here for the solution and a further explanation of my specific confusion
 

Below are pictures/details of my Sears Radial Arm Saw -- about 1970 vintage.  A while back the index/detents that are supposed to position and lock the arm at 90 degrees stopped working right.  When working properly, after the "arm latch knob" is loosened the "arm latch lever" should move something into an index/detent to position the arm positively at the 90 (crosscut) position.  The instructions say "Push the arm latch solidly with palm of hand . . . this will seat the arm index pin properly."  This is accompanied by a picture showing a hand pushing on the arm latch lever.  The arm latch lever on my saw will no longer move independent of the knob -- pushing/pulling on it will not move it. (NOTE:  There is no part on the parts diagram called an "arm index pin."  I'm guessing they mean "arm lock pin," but I'm just  guessing )

I think when I screw the knob in the latching mechanism enters the index/detent position, but I'm not sure.   It's hard to tell because the knob becomes hard to turn yet it never seems to seat solidly -- when tightened it seems to mush instead of making a solid clamp.  Even if it is going into the index/detent position it's not repeatable. 

This problem has become more obvious to me because I am trying to do an overall saw realignment.  To align the table to the saw blade you first lock the arm in the 90 indexed position then adjust the table until it is square with the saw blade.  I cannot perform this step because the 90 index position is not repeatable.  Every time I move the arm from the 90 position and return is ends up at a somewhat different angle/position. 

I assume the fact that the arm latch lever does not operate properly and the arm does not return to the same position are both caused by the same problem or at least related.

Has anyone who's ever owned this or a similar saw had this problem?  If so, what was the fix? 

How exactly is this indexing supposed to work. 

Have you ever removed the arm from the column?  I ask because it's beginning to look like I may have to do this but don't want to screw something else up.

 

 

You can go here for the solution to this problem and
an explanation of why I was confused.