What Shank is The Featherweight?

All 221 and 222 Featherweights are Low-Shank.  It was Singer's most common configuration for their household sewing machines.  The term Shank refers to the position and height of the needle bar and presser bar.  Below is a comparison of the four common machine shanks used by Singer.

The Low-Shank:

Singer's most common shank and the one that was used exclusively for the Featherweight was the Low-Shank configuration.  The low shank attachments mount on the presser bar 1/2" up.  

The Back-Clamping Shank:

The Back-Clamping shank appears to have been used primarily on the earlier 66 model Singer machines.  The attachments are taller than a Low-Shank and they are screwed on from the back of the presser bar.  The Back-Clamping attachments measure about 7/8" to the mounting point.

Photo courtesy of David Werther

The High-Shank:

 A high shank won't be found on most household Singer machines, as it was used more for industrial machines, but the photo below shows its straight but taller shank.  The mounting point on a high-shank foot is about 1".  

The Slant-Shank: 

Apparently an achievement Singer was most proud of - the Slant-Shank debuted on the 301 machines.  Here is a clipping from a Singer advertisement for the new Slant-Shank machine.

The Slant-Shank attachments mount to the machine at about 7/8". 

Common questions about machine shank:

Are the feet interchangeable?  The feet are not interchangeable.  However, some owners of the 66 Back-Clamping machines have changed out the presser bar for the Low-Shank option. 

What are Snap-On Feet?  Snap-On feet are a great way to be able to use the same feet on both slant and low shank machines.  With a Snap-On adapter, a snap-on foot can be attached to the Featherweight and then taken off and used on a Slant machine with an adapter.  Here is a link to the Snap-On options for the Featherweight.