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Dick Lyon's nonpatent table of Otis King's patent calculators

I intend to keep the table (below) of known Otis Kings up-to-date and publicly accessible as people send me info on more Otis King's patent calculators (also known as Carbic or Geniac cylindrical or spiral slide rules, among other things).

See also my new summary table.

Many thanks to R. Hems, D. Calkins, M. Postman, J. Rogers, J. R. Ewans, A. Roberts, B. Donniger, P. Hopp, F. Stahl, A. de Man, H. Smith, J. Irving, J. Selevan, E. Chamberlain, A. Parr, R. Landsman, P. Davies, M. Rowley, E. Tedeschi, K. Rose, J. Bready, J. Lee, C. Catt, J. Williams, T. Dooley, D. Eisenschenk, C. Lampiris, A. Oliveira, L. Wilhelm, T. Sanders, B. Burns, A. Mosby, D. Maack, D. Price, C. Stoll, K. Kuehn, R. Harmic, C. Dooley, P. Clarke, D. Evans, H. Aldinger, E. Ross, F. Wells, R. Padron, P. Tripet, W. Feely, Nelson, Clive Kidd, and several anonymous others for new data.

Referenced addresses (1, 2, 3, 4) and types (A, B, C) and most other data are from Peter Hopp's articles in the Journal of the Oughtred Society (vol. 4 no. 2 and vol. 5 no. 2).


07 Sept 97: I've received word from Peter Hopp that he has also been processing lots of new serial numbers. He says: "With all the additional O-K serial numbers we seem to have at long last figured out the mysteries of the serial numbers and dating of the calculators; each new example helps us to calibrate our theory. It is hoped that the ideas will be published as a short article in the next edition of the Oughtred Society Journal by Colin Barnes who has put in a lot of thought on this vexed subject." He graciously gave me all his new data and suggested I act as "devil's advocate" in another article to offer my dating scheme as an alternative. So don't take my time line as gospel, but as one interpretation based on limited data.

18 Sept 97: I've added a bunch of new units from Peter Hopp's latest tables. There now appears to be considerable evidence for a mixture of type-B and type-C units in the R, S, and T series, and perhaps even a type-B V-series unit. Could Carbic have produced at two locations when they started selling through American companies?

28 Oct. 97: A dozen new OK's listed thanks to SRTP customers and others.

15 Nov 97: Info from Al Roberts on ten more units, of which most are currently for sale.

9 Jan. 98: Lots of new units have been added in the last month. Colin Barnes has published his dating theory in the most recent Journal of the Oughtred Society. His idea is that the letter was changed yearly, and that they cycled through the alphabet twice and then some. Some of the dates that I thought were pretty firm, like the 1935 and 1949 in the table, are very much at odds with his theory, but there are also lots of anomalies that don't fit my time line very well. We're working to get more evidence for one way or the other.

6 Apr. 98: Just finished final page edits on my article; with the Journal of the Oughtred Society editor Bob Otnes' help it's going to come out right nice. It was hard, though, because you all kept sending so much new good info as I was trying to be done with it. I'll try to get some of the late results online here soon, along with a version of the article.


These are the known addresses of Carbic Ltd.:
0: 44 & 66 Bray's Lane, Coventry (1921)
A: "Ashdene," Emscote Road, Stoke, Coventry (1922)
1: 51 Holborn Viaduct, London, EC1
2: 137 Conway Road, London, N14 (the home of a company officer?)
3: 171 Seymour Place, London, W1
4: 54 Dundonald Rd, London, SW19
(at least addresses 0, 1, 3, and 4 are found on instruction sheets or rules)


Information on classification into types A, B, and C is found on my OK types page.

The Table

Table of serial numbers, with letter prefix separated, and with model appended 
after a colon.  Dates at start apply to one or more units in that line.  Long
lines do not wrap in the preformatted table--the line lengths can be viewed as
a histogram of the known frequency of occurrence of the different serial number
series.  So open your window this wide if you can -->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->-->|

  Type D addresses 0 and 1
1921 -  131:?(address 0) 688(or889):N 867:N? 899:N(Tuck&Blakemore) 6412:?

  Type A address 1:
     - 5111:K 5513:K 5782:K 6704:K 6969:L 7450:L 7608:K 7636:L 7646:K 7765:N 8087:K 8365:N 8846:K 9201:? 9662:K 9677:L
1923 A 5107:K 5213:K 5402:K S481(5481?):K 6047:K 6141:L 6491:K 6497:K 6523:K 6524:K 6681:K 7328:K 7491:K 8534:L 8668:K 8948:K 9441:L

  Type B addresses 1 & 3 (transition time is unclear due to missing data)
     A 6306:L(says patentees) 7176:K(chrome/plastic?)
     B 4456:L 
     C  253:L 1135:L 1198:K(4?) 1232:L 1239:K 1865:K
1935 D  200:L  280:L  490:K 1094:K(C?Ni) 1145:K 1280:? 1998:K
     E 0106:L 0575:L
     F 0477:K(A?) 0488:K
     G 0015:?  298:L  312:K(3?)  629:L 1053:?(A?) 1080:K(C?)
     H  500:K 0656:K(3) 0818:K(3?) 0971:K 1369:L 1455:K (serial number under cap)
     I (none expected)
     J 0202:L 1571:K 1575:K (still varnished paper scales)
     K 0050:L  (first PCP/PF scales?)
     L (none expected)
     M 1351:L 1644:K
1949 N 0214:K 0975:L 2150:K 2164:K 3144:K 3411:K 3482:K 5707:K 6261:K 6276:L 6465:L 7021:K
     O (none expected)
     P 0114:K 0436:L 0859:K 1255:L 2601:K 2711:K 2860:L 3301:K 3657:K 3745:K
     Q (none expected)
     R 2025:K(4?) 3346:L 3733:K 4306:L
       (above are reported as type B, possibly unlike R's below)
       (R, S, and T series may have many misclassified, since B/C class was not defined in time)
     S 0818:K 2895:L 3890:L 4794:L 6005:B 6232:L 6788:K(1!)
     T 0145:K 0399:K 1030:K
  Type B/C address 4 (made in England on cap like type B, but with type C cursor & cap shape):
     R 360:L 1903:K 3474:K 3902:K
       (R1903 has address 3 overprinted with address 4)
     S 3896:L 3904:L 4028:K 4073:L 4755:K 5217:L 5260:L 
  Type C address 4 (or American addresses on some S & T series):
1957 S 0368:L 0626:L 3007:K 4754:L 5524:L 6078:K 6376:K 7780:L 8374:L 9126:L 9813:K 9826:K 9897:L
60/62T 0775:K 1445:K 1595:L 2328:L 2523:K 3239:L 4208:K 5198:K 6133:K 6514:L 6672:L 7168:? 7747:K 7893:K 8156:L
     U 0483:K 0501:K 0507:L 0765:K 1371:L 1946:L 2201:L 2410:K 2893:L 2963:K 3427:L 5914:L 6253:K 6266:K 6379:? 7058:L 7474:K 8060:K 8232:L
1960 V 0270:K 0716:K 1154:K 1305:K 2474:K 4542:L 5533:L 6111:K(3/4) 8087:L 8393:? 8592:K 8732:K 9242:L 9415:L 9524:K 9749:K
     W 0665:K 0948:L 1682:K 2222:? 3466:K 4138:L 4503:K 4939:K 5222:K 5256:K 5262:K 5291:K 7263:L 9412:K
1965 X 0631:K 0866:K 1089:K 1874:K 2170:K 3193:K 3747:L 4090:L 5222:K 5274:L 5291:L 5599:K 6099:K 7372:K 8629:K 8984:L 9656:L 9673:L
     Y 0901:L 1115:L 2172:K 2971:K 4219:L 4449:K 4605:K 4681:K 4749:K 5318:L 6126:K 6427:K 8125:K 8370:K 9966:K
1969 Z 0087:K 0548:K 1524:K 1796:L 1920:L 2277:K 3168:L 3906:K 4143:K 4644:L 5995:K 6311:L 6380:L 7379:K 7401:K 8088:L 8164:L 8203:L 8879:L

   re-used letters A & B (these have 16-page instruction leaflets, instead of 8):
1970 A 0270:K 0663:K 0811:K 0936:K 1464:K 1685:K 1740:K 2309:L 3062:L 3302:K 6141:K 6681:K 6907:L 7087:L 7165:K 7350:K 7362:L 8224:? 8277:? 8333:L 8427:L 9633:?
       (some of the above A series instructions imply decimal Sterling, some don't)
1971 B 0663:L 0886:L 1146:L 1979:L 2296:K 2314:K 2546:L 2879:K 3696:K 3923:K 3946:L 6090:K 6580:K 7337:K
       (presumably all of these B series type C units were made after decimal Sterling)

unclassifiable units:
3337:K 8630:K A7751:L B0886 B3946:L (no info on type A/B/C or other date clue)
type E model L walking cane (no serial number info)
-8984:K type C? 
-899 Tuck & Blakemore

note: 5513, 6704, A5107, A7751: Peter Hopp's table showed model and 
scale-number disprepancy.  I took the scale numbers to be correct and
always took 414,423 to be model K and 429,430 to be model L.

We seek information on additional variations, more confirming examples of the patterns found, etc. See the request for info at the bottom of the Top Otis King's page