from the web:
A Singer sewing machine with the serial number N236179 was part of a batch of 50,000 machines commissioned on July 23, 1900.
Manufacturing details
Factory: Elizabethport, New Jersey.
Based on the serial number, your machine was a Model 66 made in 1925 at the Elizabeth, New Jersey, factory.
Details on the Singer 66
The Singer Class 66 is one of the company's most recognizable and popular antique machines. It was manufactured for decades, with the "Red Eye" decal variation being especially famous.
Key features of the Class 66 include:
A "back-clamping" presser foot that is secured by a screw at the rear of the presser bar, rather than the side.
The use of a drop-in, oscillating rotary hook for the bobbin, which many users find to be smoother and quieter than later models.
A faceplate with the Singer name written in script.
Variable stitch length, which is adjusted via a lever on the machine's pillar.