Singer 111w153 - knocking sound

[Ole South]

No, at near full lift, which is about 7/16"  this old guy gets picky (if you're looking for "Perfect") at 3/8" lift he's way more forgiving. New hook, rebuilt upper tension assy, new timing belt, gear lash w/in specs... perhaps someone swapped a part (I found at least one) from a lower w15x machine that I haven't found... who knows *shrug* .  "Changing setup" is going from laminated leather strap-work to a single or double layer of canvas.

[Uwe]

The knocking sounds may come from a loose connection or play in the feed eccentric mechanism. If the feed eccentric is not adjusted to be snug, parts may shift against each other as they turn, creating a clicking or knocking sound. I’d recommend inspecting the feed eccentric on the underside of the machine to see if there’s any play in mechanism. The feed eccentric has adjustment screw that allow you to make the movement snug and smooth.

Here’s a video that shows how you can adjust the eccentric assembly to make it snug:

 

Here’s a video that shows that assembly by itself and how it can create clicking or knocking noises, essentially the same info as above: