JoeJr

I have not seen one of these aftermarket reverse/stitch length mechanisms in person, but whatever attaches it to the stitch length regulating arm inside the pillar has to be tight so it doesn't move easily. I am assuming you back off the screw on the regulator to decrease the stitch length, which shortens the portion of the screw touching the plate, allowing it to move easily to a longer stitch length setting, and it will always move to the lowest number/longest stitch length setting; I'm mostly thinking out loud. Whatever attaches your lever inside the pillar has to be tightened.

AlvaStitcher

Thank you. I will try that or else figure on taking it off completely. If I remove it, do I need to do anything else to make to work properly again? The screw looks like the original screw used to adjust the stitch length, doesn’t it?

Dressmaker

I would love to have a Revco reverse attachment . I've been looking for one. In the mean time, here are a couple of helpful Youtube videos regarding the Revco attachment and the removal and replacement of the stitch regulator.
https://youtu.be/jABd4tppWGU
https://youtu.be/mhKzyZfs8Gc

OurWorkbench

It seems like I remember someone putting one on and then taking it off. I thought someone actually gave some good info, but I can not find what I remember. I did find SINGER 66 now sewing mostly straight! and Update: Singer 66 not sewing straight, Help! I think there may be another by this user but hasn't been on QB for 4 years. Then I found a youtube video on how to put one on a model 27 which I would think would be very similar to a 66. I don't think it is something I would want to do. I do have a machine with a Revco reverse, but I haven't had it out for a long time. The only thing I did sew with it was a piece with an underbraider to see if it worked. So I don't remember having any trouble with the stitch length moving.

Janey - Neat people never make the exciting discoveries I do.