Standard Electrical Porcelain
(from Jack Tod's book: The History of the Electrical Porcelain Industry in the United States)
Standard Porcelain Styles (Drawings)
The very rapid growth of the electrical power industry in the 1890's inevitably led to a rapid state of confusion regarding acceptable methods of electrical construction and the forms of electrical apparatus turned out by a very large number of manufacturers. This randomness of material specifications and installation methods not only became a factor in the increased incidences of electrical shocks and fires, but it was creating a staggering variety of manufactured electrical equipment, especially the insulators and wire used for over-surface wiring inside buildings.
Naturally the ones most concerned with these problems were the fire insurance companies, and they were the first to act. The National Board of Fire Underwriters founded the Underwriters' Laboratories, Inc. in 1894 to formulate safety standards for the industry. Up to modern times there have been numerous agencies and national associations involved with these matters, and it is beyond the scope of this book to detail the history of the various standards and codes which have evolved.
The National Electrical Code was first published in 1897 as a result of a national conference of engineering and underwriters' organizations, and it has been periodically revised and expanded throughout the years. The Code was initially a set of rules relating to electrical installations and which were intended to prevent fire hazards, and one major section of the Code set forth standards for the materials, fittings and details of their use in electrical construction. Of interest to us here are the standards for porcelain insulators used for over-surface wiring.
The initial effect on insulators for house wiring was to standardize the forms of two-wire cleats and tubes then in use for this purpose. The standards subsequently included minimum specifications for nail knobs as they came into wide use a few years later. Of primary importance from the standpoint of fire and electrical shock were spacing of the conductors from the mounting surface and from the nail or screw used to secure the insulator. Eventually the standards even spelled out other dimensions of the insulators not involved with those factors.
Standards were also set for two other large classes of insulators which were used for surface wiring in structures other than residences. These were one-wire cleats and all forms of solid knobs. It might seem that only a small variety of insulators would be involved once standards were created, but this was not the case. Cleats had to be made for very large numbers of different conductor sizes and for varying electrical and mechanical loading factors. Knobs had to be made for an equally large number of different applications. Even at that, the Code did put a stop to the unrestrained growth of a myriad of insulator styles manufacturers were turning out.
It was fortunate that the standards were adopted as early as they were in the industry. This was before the super boom period in electrical wiring got underway. The manufacturers involved early in the game had to make only slight changes in their products, since most of the cleats and knobs made in any quantity were essentially included with only very minor changes in the standard porcelain charts. Companies entering the porcelain insulator business after the adoption of the Code made products which complied with the standards.
Not surprisingly, all the porcelain insulators used for surface wiring soon came to be known as "Standard Porcelain", and many manufacturers restricted their activities to these items. Most of the very small companies coming upon the scene in boom times made only the high-volume house wiring insulators, and the larger companies made more extensive lines of standard porcelain. Catalogs of several of the larger manufacturers had listings for virtually every size and style of standard cleats, knobs and tubes. In the case of cleats and knobs, this involved a tremendous number of dry press dies in their tooling department. In the case of tubes, it created a very large inventory of finished products. Even with porcelain insulators fairly standardized, it must have been a chore for jobbers and distributors to handle the large variety.
As differentiated from "Standard Porcelain", all porcelain insulator products not included in the standards became known as "Specialty Porcelain". Except for the very small nail knob companies in the super boom, nearly all electrical porcelain manufacturers made specialty porcelain to varying degrees, even if their main product was standard porcelain. This specialty porcelain was occasionally a proprietary product, but generally it was made on contract for other electrical manufacturers.
Manufacturers of standard porcelain tended to follow the Code in the more important features such as overall insulator size, hole diameter, groove size, etc. Standard knobs and cleats by various manufacturers did vary with regard to unimportant details such as crown curvature, beveled corners, base counterbore shape, etc. There was also some discrepancy on outline dimensions and numbering methods used by various companies. For instance, some companies list the #3-1/2 knob as a #3 W.G. (wide groove).
The Standard Porcelain chart for solid knobs is shown on the following pages. There was one major revision of the knobs in the Code wherein some items were deleted, others added, dimensions of some changed, Sizes shown are generally for the New Code (N.C.), but both sizes are shown for the #5-1/2 (which is the proverbial nail knob in split form, 5-1/2-split). The chart is nominally for solid knobs, but split knobs normally used as forestry insulators are also shown; these are the Victor #22, #37-Split and #38-Split.
As you can see, there was a "standard" knob for virtually every use. It would be interesting to know just what pull some manufacturers had to get obviously proprietary knob designs included in the Code -- notably the #17, #18, #35 and the electric fence items #57 and higher. Some of the numbers were commonly used in many types of wiring installations, but others were probably made for rather limited applications.
Click on the photo above to see a larger photo. The collection as shown contains 228 insulators and are listed below. Detailed photos of each insulator is shown in the 8 pages of photos.
The table below shows the various standard porcelain in my collection. The first number is the Standard Porcelain number. The number after the dash is a sequence number. To review a drawing for the Standard Porcelain style, go here: Standard Porcelain Drawings. To see a photo of a specific insulator, click on the Number or go here: Standard Porcelain Photos.
emb: embossed
r-e: recess-embossed
u-g: under-glaze ink
/ : marking on opposite side
// : marking on bottom
| No. | MARKING | Marking Type | Color | Company | Notes | |
|---|---|---|---|---|---|---|
| 0-01 |  |
N-N | white | |||
| 0-02 | 
 |
R T & S CO | emb | white | R. Thomas & Sons Co. | |
| ½-01 |  |
N-N | white | |||
| 1-01 | 
 |
BRUNT | emb | white | Brunt Porcelain Co. | |
| 1-02 | 
 |
MACOMB | emb | white | Illinois Electric Porcelain Co. | |
| 1-03 | 
 |
PP-1 | incuse | white | Porcelain Products Co. | |
| 1-04 | 
 |
O. P. CO. | emb | white | ||
| 1-05 |  |
R T & S CO | emb | white | R. Thomas & Sons Co. | |
| 1-06 | 
 |
PERU | emb | white | Peru Electric Porcelain Co. | |
| 1-07 | 
 |
Triangle M / 1 | emb | white | Illinois Electric Porcelain Co. | |
| 1-08 |  |
T | r-e | white | R. Thomas & Sons Co. | |
| 1-09 | 
 |
A. P. CO. | emb | white | Anderson Porcelain Co. | |
| 1-10 | 
 |
F | emb | white | Findlay Electric Porcelain Co. | |
| 1-11 | 
 |
R. P. Co. | emb | white | Ravenswood Porcelain Co. | |
| 1-12 | 
 |
FEDCO | emb | white | Federal Porcelain Co. | |
| 1-13 | 
 |
KNOX / 1 | r-e | white | Knox Porcelain Corp. | |
| 1-14 | 
 |
G | emb | white | ?? | |
| 1-15 | 
 |
T.P. (on bottom) | r-e | white | Trenton Porcelain Co. | |
| 1-16 | 
 |
E | emb | white | East Liverpool Electrical Porcelain Co. | |
| 1-17 |  |
S P (bottom) | emb | white | Superior Porcelain Co. | |
| 2-01 | 
 |
P. P. INC. / 2 | emb | white | Porcelain Products Inc. | flat top and flat bottom |
| 2-02 |
 |
PERU | emb | white | Peru Electric Porcelain Co. | short |
| 2-03 |
 |
R T & S CO | emb | white | R. Thomas & Sons Co. | tall |
| 2-04 |
 |
P. P. INC. / 2 | emb | white | Porcelain Products Inc. | round top and recessed bottom |
| 2-05 |
 |
N-N | white | |||
| 2-06 |
 |
Triangle M // 2 | emb // r-e | white | Illinois Electric Porcelain Co. | |
| 2-07 |
 |
E | emb | white | East Liverpool Electrical Porcelain Co. | |
| 2-08 |
 |
PERU | emb | white | Peru Electric Porcelain Co. | |
| 2-09 |
 |
US | incuse | white | U.S. Electric Porcelain Co. | |
| 3-01 |  |
F // F | emb | white | Findlay Electric Porcelain Co. | |
| 3-02 |  |
N-N | white | |||
| 3-03 | 
 |
THOMAS | emb | white | R. Thomas & Sons Co. | |
| 3½-01 | 
 |
P P / -2 | emb | white | Porcelain Products Inc. | |
| 3½-02 | 
 |
U S (intertwined logo) | emb | white | U.S. Electric Porcelain Co. | |
| 3½-03 | 
 |
F // F E P Co (around bottom) | emb | white | Findlay Electric Porcelain Co. | |
| 3½-04 | 
 |
F // F E P Co (around bottom) | emb | brown | Findlay Electric Porcelain Co. | |
| 3½-05 | 
 |
G P Co. / 3½ | emb | white | ||
| 3½-06 | 
 |
Triangle M | emb | white | Illinois Electric Porcelain Co. | |
| 3½-07 | 
 |
No. 3½ / DIEN01 (all markings on bottom) | emb | white | ?? | |
| 3½-08 | 
 |
P. P. Inc. U.S.A. / 3½ | emb | white | Porcelain Products Inc. | |
| 3½-09 | 
 |
A. P. CO // 3½ | emb | white | Anderson Porcelain Co. | |
| 3½-10 | 
 |
E | emb | white | East Liverpool Electrical Porcelain Co. | |
| 4-01 |  |
N-N | white | |||
| 4-02 |  |
T | r-e | white | R. Thomas & Sons Co. | |
| 4-03 |  |
N-N (short) | white | |||
| 4-04 |  |
N-N (shorter) | white | |||
| 4-05 | 
 |
R. T. & SON'S (bottom) | emb | white | R. Thomas & Sons Co. | |
| 4-06 |  |
N-N (different shape) | white | |||
| 4-07 | 
 |
Diamond (bottom) | inc | white | Diamond Porcelain Co. | |
| 4-08 | 
 |
SPCO (bottom) | emb | white | Superior Porcelain Co. | |
| 4-09 | 
 |
US (intertwined) | emb | white | U. S. Electric Porcelain Co. | |
| 4-10 |  |
N-N | white | deep cone bottom | ||
| 4-11 |  |
UPW and eagle head | u-g ink | white | Union Porcelain Works | flat bottom |
| 4-12 |  |
N-N | white | |||
| 4-13 |  |
N-N | gray | |||
| 4-14 |  |
N-N | white | |||
| 4-15 | 
 |
HF (bottom) | emb | white | Hartford Faience Co. | |
| 4-16 |  |
F. P. CO. | emb | white | Franklin Porcelain Co. | |
| 4-17 |  |
UPW and eagle head | u-g ink | white | Union Porcelain Works | recessed bottom |
| 4-18 |
 |
A.P. CO. | emb | white | Anderson Porcelain Co. | |
| 4½-01 | 
 |
E | emb | white | East Liverpool Electrical Porcelain Co. | small |
| 4½-02 |  |
N-N | white | |||
| 4½-03 | 
 |
E. P. (bottom) | emb | white | Electrical Porcelain Co. | |
| 4½-04 |  |
T | r-e | white | R. Thomas & Sons Co. | |
| 4½-05 |  |
N-N | white | cone top | ||
| 4½-06 |  |
G | emb | white | ?? | |
| 4½-07 | 
 |
GLOBE | emb | white | Globe Porcelain Co. | |
| 4½-08 | 
 |
FEDCO | emb | white | Federal Porcelain Co. | |
| 4½-09 | 
 |
SUPERIOR / No. 5½ | emb | white | Superior Porcelain Co. | |
| 4½-10 | 
 |
T // 1 | r-e/emb | white | R. Thomas & Sons Co. | |
| 4½-11 | 
 |
A I & M CO (bottom) | emb | pottery | Akron Insulator & Marble Co. | |
| 4½-12 |  |
E | emb | white | East Liverpool Electrical Porcelain Co. | |
| 4½-13 | 
 |
M | emb | white | Illinois Electric Porcelain Co. | |
| 4½-14 |  |
N-N | white | |||
| 4½-15 |  |
T | r-e | white | R. Thomas & Sons Co. | larger |
| 4½-16 | 
 |
T | r-e | white | R. Thomas & Sons Co. | smaller |
| 4½-17 |  |
F (bottom) | emb | white | Findlay Electric Porcelain Co. | |
| 4½-18 |  |
G | emb | white | ?? | smaller |
| 5-01 | 
 |
SUPERIOR / 5 | emb | white | Superior Porcelain Co. | |
| 5-02 | 
 |
P. P. INC. / 5 / U.S.A. / 5 (in a circle) | emb | white | Porcelain Products Inc. | |
| 5-03 | 
 |
A M C (bottom) | emb | white | American Marble & Toy Mfg. Co. | |
| 5-04 |  |
N-N | white | flat on bottom | ||
| 5-05 |  |
N-N | white | cone top, recessed bottom | ||
| 5-06 |  |
N-N | white | deep cone bottom | ||
| 5-07 |  |
BRUNT | emb | white | Brunt Porcelain Co. | |
| 5-08 |  |
N-N | white | larger | ||
| 5-09 | 
 |
P P INC | emb | cobalt blue | Porcelain Products Inc. | |
| 5-10 |  |
F (bottom) | emb | white | Findlay Electric Porcelain Co. | |
| 5-11 | 
 |
WIS-P-C. / USA | emb | white | Wisconsin Porcelain Co. | |
| 5-12 | 
 |
WP / 5 / USA | emb | white | Wisconsin Porcelain Co. | |
| 5½-01 | 
 |
U / 5½ | r-e | white | Universal Clay Products Co. | |
| 5½-02 |  |
?? | white | |||
| 5½-03 | 
 |
P / 5 (bottom) | emb | white | ||
| 5½-04 | 
 |
CANTON (bottom) | emb | white | ?? | |
| 5½-05 | 
 |
P / 5 (bottom) | emb | white | ||
| 5½-06 |  |
SUPERIOR / 5½ | emb | white | Superior Porcelain Co. | |
| 5½-07 |  |
P & S (on side) | emb | white | Pass & Seymour, Inc. | |
| 5½-08 | 
 |
BRUNT | emb | white | Brunt Porcelain Co. | |
| 5½-09 | 
 |
P. P. INC. / 62 / U.S.A. / 5½ (circle) | emb | white | Porcelain Products Inc. | |
| 5½-10 | 
 |
KNOX / 5½ | r-e | white | Knox Porcelain Co. | |
| 5½-11 | 
 |
T | r-e | white | R. Thomas & Sons Co. | |
| 5½-12 | 
 |
T | r-e | white | R. Thomas & Sons Co. | larger |
| 5½-13 | 
 |
Triangle M / 5½ | r-e | white | Illinois Electric Porcelain Co. | |
| 5½-14 | 
 |
US (intertwined) | emb | white | U.S. Electric Porcelain Co. | |
| 5½-15 | 
 |
P. P. INC. / 5½ | emb | white | Porcelain Products Inc. | |
| 5½-16 |  |
F (bottom) | emb | white | Findlay Electric Porcelain Co. | |
| 5½-17 | 
 |
Diamond (bottom) | incuse | white | Diamond Porcelain Co. | |
| 5½-18 | 
 |
E | emb | white | East Liverpool Electrical Porcelain Co. | |
| 5½-19 | 
 |
THOMAS | emb | white | R. Thomas & Sons Co. | |
| 5½-20 | 
 |
HP / B (bottom) | emb | white | Akron High-Potential Porcelain Co. | |
| 5½-21 | 
 |
KNOX / 5½ | r-e | white | Knox Porcelain Co. | different marking than 5½-10 |
| 5½-22 | 
 |
THOMAS | emb | white | R. Thomas & Sons Co. | |
| 6-01 | 
 |
F | emb | white | Findlay Electric Porcelain Co. | |
| 6-02 | 
 |
BRUNT | emb | white | Brunt Porcelain Co. | |
| 6-03 | 
 |
S. P. Co. / 6 | emb | white | Superior Porcelain Co. | |
| 7-01 |  |
F | emb | white | Findlay Electric Porcelain Co. | |
| 7-02 | 
 |
?? | white | |||
| 7-03 | 
 |
SUPERIOR / No. 7 | emb | white | Superior Porcelain Co. | |
| 7-04 |  |
N-N | white | |||
| 7-05 |  |
N-N (Thomas) | white | R. Thomas & Sons Co. | ||
| 8-01 |  |
N-N (Findlay) | white | Findlay Electric Porcelain Co. | ||
| 9-01 |  |
N-N | white | cone bottom | ||
| 9-02 |  |
N-N | white | flat bottom | ||
| 10-01 | 
 |
BRUNT | emb | white | Brunt Porcelain Co. | |
| 11-01 | 
 |
BRUNT | emb | white | Brunt Porcelain Co. | cone bottom |
| 12-01 | 
 |
F | emb | white | Findlay Electric Porcelain Co. | F parallel to side |
| 12-02 | 
 |
F | emb | white | Findlay Electric Porcelain Co. | F perpendicular to side |
| 12-03 |  |
F | emb | white | Findlay Electric Porcelain Co. | F parallel to side |
| 12-04 | 
 |
G. P. Co. | emb | white | General Porcelain Co. | |
| 13-01 |  |
F | emb | white | Findlay Electric Porcelain Co. | |
| 14-01 |  |
N-N | white | |||
| 14-02 | 
 |
S. P. CO. (bottom) | emb | white | Superior Porcelain Co. | |
| 15-01 | 
 |
PERU | emb | white | Peru Electric Porcelain Co. | |
| 15-02 | 
 |
F | emb | white | Findlay Electric Porcelain Co. | |
| 16-01 |  |
N-N | white | |||
| 16-02 |  |
U (bottom) | r-e | white | Universal Clay Products Co. | |
| 16-03 | 
 |
WP6 / U.S.A. | r-e | white | Wisconsin Porcelain Co. | |
| 16-04 | 
 |
N E T & T | r-e | white | New England Telephone & Telegraph Co. | |
| 16-05 |  |
U.S.A. / U.S.A. | emb | white | ||
| 16-06 | 
 |
HP / P / S / 55 (bottom radially) | r-e | white | ||
| 16-07 | 
 |
KNOX / 7138-S | r-e | white | ||
| 16-08 |  |
T (bottom) | r-e | white | R. Thomas & Sons Co. | |
| 16-09 | 
 |
U.S.A. (bottom) | r-e | white | ||
| 16-10 | 
 |
N. E. T. & T. CO. | r-e | white | New England Telephone & Telegraph Co. | |
| 16-11 |  |
T | r-e | white | R. Thomas & Sons Co. | |
| 18-01 |  |
N-N | white | |||
| 20-01 |  |
N-N | emb | white | very rounded | |
| 20-02 | 
 |
P. P. INC. / NO. 20 | emb | white | Porcelain Products Inc. | |
| 20-03 |  |
F | emb | white | Findlay Electric Porcelain Co. | |
| 20-04 | 
 |
MACOMB | emb | white | Illinois Electric Porcelain Co. | |
| 20-05 | 
 |
Triangle M | emb | white | Illinois Electric Porcelain Co. | |
| 20-06 | 
 |
R. T. & S. CO. | emb | white | R. Thomas & Sons Co. | |
| 20-07 |  |
Triangle M | emb | cobalt blue | Illinois Electric Porcelain Co. | |
| 21-01 |  |
N-N (Thomas) | white | R. Thomas & Sons Co. | ||
| 22-01 | 
 |
N-N | white | |||
| 23-01 |  |
N-N | white | recessed bottom | ||
| 23-02 |
 |
N-N | white | flat bottom, skinny | ||
| 23-03 |
 |
N-N | white | flat bottom | ||
| 23-04 |
 |
F (bottom) | emb | white | Findlay Electric Porcelain Co. | tall |
| 23-05 |
 |
N-N | white | very rounded | ||
| 23-06 |
 |
F (bottom) | emb | white | Findlay Electric Porcelain Co. | short |
| 23-07 |
 |
N-N (Colonial) | white | flat bottom | ||
| 23-08 |
 |
N-N | gray | |||
| 23-09 |
 |
N-N | white | very rounded, like 23-05, no mold lines | ||
| 24-01 |
 |
S# 145458 (bottom) | r-e | brown | ?? | |
| 24-02 |
 |
F | emb | white | Findlay Electric Porcelain Co. | |
| 24-03 |
 |
N-N (S. P. Co.) | ||||
| 24-04 |
 |
A M C (bottom) | emb | pottery | Akron Marble Co. | |
| 24-05 |
 |
PERU | emb | white | Peru Electric Porcelain Co. | |
| 24-06 |
 |
R T & S CO // R T & S CO | emb | white | R. Thomas & Sons Co. | |
| 24-07 |
 |
Triangel M | emb | white | Illinois Electric Porcelain Co. | |
| 24-08 |
 |
THOMAS | emb | mustard brown | R. Thomas & Sons Co. | |
| 24-09 |
 |
MACOMB | emb | white | Illinois Electric Porcelain Co. | |
| 24-10 |
 |
N-N | chocolate brown | 3 firing teats on bottom | ||
| 24-11 |
 |
P.P. U.S.A. / NO. 24. | emb | white | Porcelain Products Inc. | |
| 25-01 |
 |
F | emb | white | Findlay Electric Porcelain Co. | |
| 25-02 |
 |
E P | emb | white | Electrical Porcelain Co. | |
| 26-01 |
 |
PERU | emb | white | Peru Electric Porcelain Co. | smaller, small hole |
| 26-02 |
 |
PERU | emb | white | Peru Electric Porcelain Co. | larger, large hole |
| 26-03 |
 |
R T & S CO // R T & S CO | emb | white | R. Thomas & Sons Co. | smaller wire groove |
| 26-04 |
 |
R T & S CO // R T & S CO | emb | white | R. Thomas & Sons Co. | larger wire groove |
| 29-01 |
 |
MACOMB | emb | white | Illinois Electric Porcelain Co. | 2-part glazeweld |
| 29-02 |
 |
F | emb | white | Findlay Electric Porcelain Co. | |
| 29-03 |
 |
BRUNT // BRUNT | emb | white | Brunt Porcelain Co. | 2-part glazeweld |
| 29-04 |
 |
U.S.A. P. P. INC. / NO. 29 | emb | white | Porcelain Products Inc. | 2-part glazeweld |
| 29-05 |
 |
A | emb | white | ?? | |
| 29-06 |
 |
N-N | white | |||
| 30-01 |
 |
THOMAS | emb | white | R. Thomas & Sons Co. | |
| 31-01 |
 |
N-N (Globe) | white | Globe Porcelain Co. | ||
| 31-02 |
 |
NATIONAL NO. 31. | r-e | white | National Metal Molding Co. | |
| 32-01 |
 |
N-N | white | |||
| 32-02 |
 |
PERU | emb | white | Peru Electric Mfg. Co. | |
| 35-01 |
 |
N-N | tan | |||
| 35-02 |
 |
N-N | white | |||
| 35-03 |
 |
N-N | brown | |||
| 36-01 |
 |
F | emb | white | Findlay Electric Porcelain Co. | smaller |
| 36-02 |
 |
N-N | white | |||
| 36-03 |
 |
G | emb | white | ?? | lareger |
| 36-04 |
 |
KNOX / 36 | r-e | white | Knox Porcelain Co. | |
| 37-01 |
 |
F | emb | choc brown | Findlay Electric Porcelain Co. | |
| 37-02 |
 |
P. P. U.S.A. 37 (circle) | emb | white | Porcelain Products Inc. | |
| 37-03 |
 |
R T & S CO // R T & S CO | emb | white | R. Thomas & Sons Co. | |
| 37-04 |
 |
F | emb | white | Findlay Electric Porcelain Co. | narrow wire groove |
| 37-05 |
 |
F | emb | white | Findlay Electric Porcelain Co. | wide wire groove |
| 37-06 |
 |
WP36 / USA | r-e | white | Wisconsin Porcelain Co. | |
| 37-07 |
 |
USA (bottom) | r-e | white | ?? | |
| 37-08 |
 |
N-N | ||||
| 37S-01 |
 |
R T & S CO | emb | white | R. Thomas & Sons Co. | |
| 39-01 |
 |
F | emb | white | Findlay Electric Porcelain Co. | 2-part glazeweld |
| 39-02 |
 |
F | emb | gray | Findlay Electric Porcelain Co. | 2-part glazeweld, larger |
| 39-03 |
 |
39 | emb | white | ||
| 45-01 |
 |
FINDLAY / 1925 | emb | white | Findlay Electric Porcelain Co. | small |
| 45-02 |
 |
F | emb | white | Findlay Electric Porcelain Co. | |
| 45-03 |
 |
US | emb | white | U.S. Electric Porcelain Co. | |
| 45-04 |
 |
FINDLAY / 1926 // F | emb | white | Findlay Electric Porcelain Co. | |
| 45-05 |
 |
PP 1180 | emb | white | Porcelain Products Inc. | |
| 46-01 |
 |
F | emb | white | Findlay Electric Porcelain Co. | |
| 48-01 |
 |
T | emb | white | R. Thomas & Sons Co. | |
| 50-01 |
 |
F | emb | white | Findlay Electric Porcelain Co. | |
| 51-01 |
 |
N-N (G. P. Co.) | white | General Porcelain Co. | ||
| 51-02 |
 |
THOMAS // THOMAS | emb | white | R. Thomas & Sons Co. | |
| 51-03 |
 |
MADE IN U.S.A / T51 // (repeated on bottom) | r-e | white | R. Thomas & Sons Co. | |
| 51-04 |
 |
OB | u-g ink | white | Ohio Brass | |
| 57-01 |
 |
PAT. NO. 108489. | emb | white | Porcelain Products Inc. | design patent 108,489 |
| 59-01 |
 |
P. P. INC. / 58 / U.S.A. / 58 (circle) | emb | white | Porcelain Products Inc. | |
| 59-02 |
 |
PRIME | emb | brown | ?? | |
| 59-03 |
 |
PRIME | emb | cobalt blue | ?? | |
| 61-01 |
 |
WP-23 / USA | emb | white | Wisconsin Porcelain Co. | |
| 61-02 |
 |
S. P. Co. / No. 666 | emb | white | Superior Porcelain Co. | |
| 61-03 |
 |
P. P. INC. / 61 / U.S.A. / 61 | emb | white | Porcelain Products Inc. | |
| 61-04 |
 |
Sears / USA | emb | white | Wisconsin Porcelain Co. | |
| 61-05 |
 |
WP 22 / USA | emb | white | Wisconsin Porcelain Co. | |
| 61-06 |
 |
WP 23 / USA | emb | white | Wisconsin Porcelain Co. | |
| 62-01 |
 |
P P INC / 62 / U.S.A. / 5½ (circle) | emb | white | Porcelain Products Inc. | |
| 62-02 |
 |
CROSS COUNTRY | emb | white | ?? | |
| 62-03 |
 |
N-N | white |
Standard Porcelain Styles (Drawings)
