15" Sears variable speed lathe top pulley

[pankr003]

I saw several posts from several years ago about what I assume was an older version of the 15" Sears lathe. The one I have is about a year old. It worked pretty well until the last month or so when what I was turning began to stop when I set the hand wheel dial below about 500 rpms. Now if I press with what used to be normal force and use sharp tools the work slows down at 1000 rpms. I pulled the covers off to see what I could learn and noticed that although half of the bottom pulley moved left and right, the moveabvle (?) top pulley with the spring never moved (I measured it at about 500 and 2000 rpms and the measurement of the widths was the same. I had assumed the variable speed belt was worn and had gotten smaller and ordered a new one. When it came the new one did not look much different than the one on the lathe so I have not tried to install it yet. When I tried measuring the two belts I came up with the same measurements. Have any of you seen anything similar and what did you do to fix the problem? Thanks.

[Charley]

I have a variable speed Delta drill press with this type of speed adjustment and shortly after I bought it the steel insert in the middle of this aluminum pulley pulled out of the aluminum. This caused a different type of failure, but I got to inspect the way it was made real well. You've got to figure out why the top pulley doesn't move, maybe it needs some lubrication, etc. Those pulleys usually have a kind of spline in the sides facing the belt. As the sides move together these splines mesh which allows the working surface (where the belt touches) to move higher toward the outer edges. Maybe there's something stuck in one of the splines, perventing the mating spline from meshing, or maybe the steel insert has rotated in the pulley. It also has a spline that rides in a spline on the shaft and if the pulley spline and the shaft spline move in relation to one another the pulley splines may be hitting each other and not meshing like they are supposed to. The spring pressure has to be removed and then a careful inspection of the pulley must be made. Only then will you be able to figure out what is causing the binding problem.

[pankr003]

I got the lathe apart and cleaned the pulley and it moves freely now. Thanks for the help.