Originally Posted by BoJangles

Here is what I have found.

66-1 Egyptian 1902 -06 Scroll 1906 - 23 back clamping treadle
66-3 HC Back clamping
66-4, 1923- side clamping treadle
66-5 side clamping HC
66-6 1921-31 side clamping electric
66-8 side clamping
66-13 side clamping 1920 +
66-14 side clamping with reverse
66-14 thru 66-24 reverse and side clamping

66 was made between 1902 and 1956

This is what I found out when I was doing all the research on side clamping versus back clamping 66's.

Nancy
This is where I got this information.

http://www.ismacs.net/singer_sewing_...sses-1-99.html