21940KBR

I found the link to you SB  serial number guide on hobby-machinist. Thanks for such a great resource!
I just purchased this lathe and really have no idea when it was made, although I suspect in was in the mid-fifties.
The serial number is 21940KBR – (could that be an OH versus a ZERO?). Opposite that is another number stamped on the bed B400NK.
Included with the lathe was some (original?) literature:
1)  Catalog number 5600, gold colored, 50th anniversary edition copyrighted 1955.  This was contained in a manila envelope with a South Bend postmark for 6 ½ cents. Stapled within the catalog was an IBM punch card with a hand a written note which reads:
Model B10K
4 ½ ft, 667R
 $  497.00 
Tool Block 1413N
 $   13.50 
3 Jaw 6506
 $  107.00 
Steady rest 2395K
 $   15.75 
Follow rest 2400K
 $   10.50 
4 Jaw 4006K
 $   42.00 
8” Face plate
 $     9.75 
Jacobs Chuck
Thread Gauge
 $   11.75 
At the bottom of the note, written ink “Wrote 7/2/56”
2)  How to run a lathe, 49th edition, copyright 1949
3)  Accessory Bulletin titled “Profit Makers” “South Bend Lathe Accessories” copyright 1973. In handwriting on the front cover it reads “Sept. 1973”.On the inside back cover, titled notes, a handwritten note reads, “Bought Lathe at auction July 12, 2003 $1450.00”
Both of the above manila envelopes were addressed to the same person, whom I presume was the original owner. 
This is such a beautiful machine that I had to attach a bunch of photos. Of note (at least to me) is that the hand scrape marks (frosting?) are still clearly visible and show no signs of wear. Aside from needing to be cleaned and lubricated, the machine appears to be in “as new” condition!
I’m going to post this on the hobby-machinist web site, omitting the original owners name….please feel free to use this on your website as well.
I hope you find this useful for your website. Any feedback you can provide would be greatly appreciated.