Nail Knobs, Split Knobs

and Other House Wiring

Knob Insulators

 

R=∞ Home

Nail Knobs page:   

Catalog pages

Patents for Knobs

Cleats

 

Nail knobs were commonly used for house wiring, which had an insulated covering.  Wall tubes were also used to go through studs and rafters.  Here are few photos that show how they were used.  Not all the split knobs shown on this web page are "nail knobs" as many styles were intended to be mounted with wood screws.

 

 

Below is a listing of nail knobs in my collection.  Please note the following legend when reading the table.  Click on the Category Number to see a photo of the insulator or go to the pages with photos of all insulators listed below:

 

R = round (standard diameter) nail knob

RR = round reversible knob

O = oval

S = square or rectangular

SR = square or rectangular reversible knob

/ = marking on opposite side

// = marking on bottom

Patents for Knobs - Click on this link to see a list of all the knob patents.

 

No. No. MARKING Marking Type Patent Company Notes
    Nail Knobs        
R-132 ( ?? )       1-3/16" diameter; thick bottom with 3 firing rest teats
R-27 (illegible patent date) emb 907,251 Colonial Sign & Insulator Co. specimen found at Colonial
R-102 2 (top) // 4 (under bottom) emb     1-1/8" diameter
R-112 (don't have) ALLIGATOR     (Porcelain Products Inc.) radial ribs under cap
R-56

 

A P C L r-e     1" diameter (possibly made by Thomas, see R-45)
R-32 A. P. CO. G. E. CO. 9419 (circle) emb   Anderson Porcelain Co. cap only; 1-1/2" diameter
R-55

B & D JR / PAT 9-3-07 // B emb 864,947   1" diameter
R-66

B & D PAT // K emb/r-e     1" diameter; 1 wire; offset nail
R-73

B & D emb     1" diameter
R-101 B.&.D. / PAT. / IMP / 07. emb   Buffinton & Dow Imperial Porcelain Works; 1-1/8"
R-02 BMOCAM (Macomb) emb   Illinois Electric Porcelain Co. matching V-grooves on cap and base
R-18 BRUNT (backward N) emb 917,207 Brunt Porcelain Co. 1" diameter, nail hole offset; matching V-grooves
R-82 BRUNT / CINCH emb   G. F. Brunt Porcelain Co. radially ribbed cap; captivated nail
R-121

 

BRUNT / CINCH // BRUNT emb   G. F. Brunt Porcelain Co. 1" diamter; radially ribbed cap; captivated nail
R-15

BRUNT / CINCH // BRUNT emb   G. F. Brunt Porcelain Co. radially ribbed cap; captivated nail
R-116 BRUNT / PAT-FEB-3-1920 emb 1,329,656 G. F. Brunt Porcelain Co. radially ribbed cap
R-131 BRUNT / PAT-FEB-3-1920 emb 1,329,656 G. F. Brunt Porcelain Co. radially ribbed cap
R-76 C  (B on bottom edge)  r-e   1" diameter
R-89 C / 800 / C (dot inside each C) emb     1-1/8" diameter, unglazed
R-113 CAREY / OHIO emb   Carey Ohio Porcelain Co. Concentric rings under cap
R-85 CCE / D // CCE / D inc/r-e     1-1/8" x 1-1/2" (Canadian)
R-115 CORWICO / USA emb      
R-96 C:S:I:CO / AKRON (in recessed band; cap projection) r-e   Colonial Sign & Insulator Co. 1-3/16" diameter
R-79 DIXIE SCREW-IT PAT.JAN.7,1919. emb 1,290,540 J. H. Parker & Son 1-3/16" diameter; 6-prong star under cap
R-80 DIXIE NAILIT PAT. JAN.7,1919-FEB.3,1920. emb 1,290,440 and 1,329,656 J. H. Parker & Son 1-3/16" diameter; 6-prong star under cap
R-44 D P Co / EVER  READY (in circle) r-e   Davidson Porcelain Co. concentric rings under cap
R-62 EFFICIENCY emb   The Efficiency Electrical Co. center extends down inside the bottom
R-68 F (under bottom) emb     1-1/8" diameter; boxed projection on cap fits in bottom
R-127 F // F (under bottom) emb   Findlay Electric Porcelain Co. 1-1/8" diameter; boxed projection on cap fits in bottom
R-12

FEDCO emb   Federal Porcelain Co. corrugated cap; captivated nail
R-126 FEDCO emb   Federal Porcelain Co. 1-3/16" diameter, flat top, corrugated cap; captivated nail
R-92 FEDCO emb   Federal Porcelain Co. corrugated cap; captivated nail
R-103 FEDCO PAT. 1.16.12. emb   Federal Porcelain Co. 1-1/8" corrugated cap; captivated nail
R-114 FEDCO PAT. 1.16.12. emb   Federal Porcelain Co. 1-1/8" corrugated cap; captivated nail
R-42 FINDLAY (backward N) / ALLIGATOR emb   Findlay Electric Porcelain Co. corrugated cap
R-43 G emb 917,207   1" diameter, nail hole offset; matching V-grooves on cap and base
R-41 GEE PEE emb   General Porcelain Co. radially ribbed cap
R-31 GRIP IT / PAT. r-e 1,429,369 J. H. Parker & Son cap only
R-84 GRIPIT / G. P. CO. PATD r-e 1,429,369 General Porcelain Co. 1-1/8" diameter; made for J. H. Parker & Son
R-17 IDEAL // PATENTED / 5 28 07 emb/r-e 855,208 Star Porcelain Co.  
R-94 KNOX (in recessed band) r-e   Knox Porcelain Corp. 1-1/8" diameter
R-54

KNOX / 5 1/2 r-e   Knox Porcelain Corp. 1-1/8" diameter
R-118 (don't have) KNOX / 5 1/2 r-e   Knox Porcelain Corp. 1-1/8" diameter
R-86 KNOX / KNOB r-e   Knox Porcelain Corp. 1-1/8" diameter
R-99 'KNOX / KNOB r-e   Knox Porcelain Corp. 1-1/8" diameter
R-100 KNOX / NAILIT r-e   Knox Porcelain Corp. 1-1/8" diameter
R-95 KNOX PAT. APPLD FOR (in recessed band) r-e   Knox Porcelain Corp. 1-1/8" diameter
R-01 MACOMB emb   Illinois Electric Porcelain Co.  
R-16 MACOMB emb   Illinois Electric Porcelain Co. ribbed channels in cap and base
R-11 MONOWATT emb   ?? concentric ring under cap; captivated nail
R-123 N (cap) // N (under bottom) emb     1" diameter
R-128 N (in trough of base) [no cap] emb     1-1/4" diameter; shown in Trenton Porcelain catalog as "Detroit split insulator"
R-14

NAILIT / PAT APPD FOR r-e 1,329,656 J. H. Parker & Son radially ribbed cap; captivated nail
R-98 NAILIT / PAT APPLD FOR emb 1,329,656 J. H. Parker & Son radially ribbed cap; captivated nail
R-117 NAILIT / PAT.APPLD.FOR (backward N) emb 1,329,656 J. H. Parker & Son radially ribbed cap; captivated nail
R-108 (don't have) NAILIT / PAT-APPLD.FOR. r-e 1,329,656 J. H. Parker & Son radially ribbed cap; captivated nail
R-35 NAILIT / PAT FEB. 3, 1920 (backward N) emb 1,329,656 J. H. Parker & Son radially ribbed cap
R-71 NAILIT. / PAT.  2  3, 1920 emb 1,329,656 J. H. Parker & Son 1-3/16" diameter; radially ribbed cap
R-119 NAILIT. / PAT. 2 3. 1920. r-e 1,329,656 J. H. Parker & Son 1-3/16" diameter; concentric ribbed cap
R-122 (don't have) NAILIT. / PAT. 2. 3. 1920. emb 1,329,656 J. H. Parker & Son 1-3/16" diameter; concentric ribbed cap
R-50

NAT / READY emb   National Electric Porcelain Co. 1-1/8" diameter; radial ribs under cap
R-39 NAT. / READY / PAT / 2-3-20. emb 1,329,656 National Electric Porcelain Co. unglazed; radially ribbed cap; captivated nail
R-106 NET&TCO (bottom is stamped with anchor logo) r-e   New England Tel & Tel Co 1" in diameter
R-06 N-N       cone top, cone recessed bottom; corrugated cap with raised ring around outside; captivated nail
R-133 N-N       cone-shaped cap with concentric ribbs underneath
R-08 N-N       rounded top, cone recessed bottom
R-09 N-N       rounded top, deep recessed bottom
R-26 N-N   965,723 Paragon Electric Co. ball fits on top of the base
R-28 N-N   907,251 Colonial Sign & Insulator Co.  
R-57

N-N       1-3/16" diameter
R-75

N-N       1" diameter
R-124 (don't have) N-N        
R-81 N-N (Brookman patent)   1,640,815   1-3/16"; off-set nail, white glazed
R-110 (don't have) N-N (top of cap recessed with spokes)        
R-105 O.I.&C.CO. r-e   Octagon Insulator & Ceramic Co. 1-1/8" diameter
R-05 P.P. INC. / ALLIGATOR emb   Porcelain Products Inc. captivated nail with "12" embossed on nail head; corrugated under cap with raised ring around outside
R-37 P.P. INC. / ALLIGATOR / 5 emb   Porcelain Products Inc. captivated nail
R-97 P.P. INC. / ALLIGATOR / 5 emb   Porcelain Products Inc. captivated nail
R-87 P. P. INC. / 9420 emb   Porcelain Products Inc. 2" diameter
R-30 PATD - FEB - 3 - 1920 (circle) // PATD / F (under bottom) emb 1,329,656 Illinois Electric Porcelain Co. cap corrugated underneath; bottom unglazed; captivated nail
R-104 (don't have) PATD FEB -3-1920- (circle) emb 1,329,656 Illinois Electric Porcelain Co.  
R-49

PAT'D / 10-22-12. emb 1,042,372   1-1/8" diameter
R-58

PAT'D / FEB 26 1907 r-e 845,544 The Electric Good Mfg Co. 1-1/8" diameter
R-33 PAT'D / JULY / 19 - 92 (on side) emb 479,134   Conover patent
R-88 N-N // PATENT PENDING (under bottom) emb 965,723 Paragon Electric Co. ball fits on top of the base
R-52

PATENT / PENDING / M emb     1-3/16" diameter
R-29 PATENTED MAY 13 1902 (circle on top) r-e 699,761    
R-134 PATENT APPLIED FOR (circle on top) r-e 699,761   patent is May 13, 1902
R-48 PHILCO r-e   Philco Radio Corp. Black glaze
R-34 POLK / PAT'D MCH 10 emb 724,329   Top is 2-1/4" in diameter with three flanges on top for tying wire around the knob; saw-toothed bottom edge prevents turning; patent date is March 31, 1903
R-90 PSW / 110 / UL r-e   Specialty Porcelain Works 1-1/8" diameter, typo of R-07 (SPW); concentric rings under cap; captivated nail
R-63 R P CO emb     1-3/16" diameter
R-51

 

S (on bottom) emb     1" diameter
R-77 S - S (S S under bottom) r-e/emb     1-1/2" diameter
R-120 SMTCO r-e   Southern Massachusetts Telephone Co. 1" diameter
R-67 S P emb     1-1/8" diameter
R-19

SPW (inside a diamond) emb   Specialty Porcelain Works 3/4" diameter, unglazed
R-07 SPW / UL / 110 r-e   Specialty Porcelain Works concentric rings under cap; captivated nail
R-03 SUPERIOR / 5 emb   Superior Porcelain Co. corrugated cap and ring outside; captivated nail
R-45 T emb   R. Thomas & Sons Co. 1" diameter, nail hole offset; matching slot
R-78 T in a circle recessed in a square r-e   Trumbull Electric Mfg. Co. 1-3/16" diameter
R-83 THOMAS emb   R. Thomas & Sons Co. 1-3/16" diameter
R-130 THOMAS r-e   R. Thomas & Sons Co. 1-3/16" diameter; concentric rings under cap
R-38

T - P - CO. / JIFFY / No 1 // PATD 12-8-03 emb 745,999 Trenton Porcelain Co. Patent shows a ball top part, but this is a standard-looking nail knob. Raised ring under cap; captivated nail
R-74

T - P - CO. / JIFFY / No 2 // PATD 12-8-03 emb 745,999 Trenton Porcelain Co. Patent shows a ball top part, but this is a standard-looking nail knob. Raised ring under cap; captivated nail
R-70 T - P - CO. - MIDGET - 80 - (in circle) emb   Trenton Porcelain Co. 1" diameter; cap only
R-69 T. P. CO. / 80 emb   Trenton Porcelain Co. 1-3/16" diameter; cap only
R-107 Triangle M emb   Illinois Electric Porcelain Co. 1-1/8" diameter
R-36 Triangle M / BULL DOG r-e   Illinois Electric Porcelain Co. unglazed; radially ribbed cap; captivated nail
R-93 Triangle M / X / BULL DOG r-e   Illinois Electric Porcelain Co. glazed; radially ribbed cap; captivated nail
R-125 Triangle M / BULL / E / DOG r-e   Illinois Electric Porcelain Co. 'unglazed where r-e BULL DOG; radially ribbed cap
R-53

Triangle M / PAT FEB 3 1920 // BULL - DOG r-e / emb   Illinois Electric Porcelain Co. 1-3/16" diameter
R-40

Triangle M / PAT FEB 3 1920 // BULL DOG 98 r-e / emb 1,329,656 Illinois Electric Porcelain Co. radially ribbed cap
R-13 Triangle M PATD FEB 3 1920 // BULL DOG r-e 1,329,656 Illinois Electric Porcelain Co. captivated nail; radial ridges under cap
R-59

U / 5 1/2 r-e     1-1/8" diameter
R-10

WEDGE / C. P. CO. PATD; (top of bottom part: PAT. APR. 27, 1909) r-e 919,386

1,218,181

Cook Pottery Co. bottom has 1 groove and 3 recessed slots underneath; radial ridges under cap; patents 919,386 and 1,218,181
R-129 WEDGE / C. P. CO. PATD r-e 919,386

1,218,181

Cook Pottery Co. bottom has 2 grooves and 3 recessed slots underneath; radial ridges under cap; patents 919,386 and 1,218,181
R-109 (don't have) WEDGE // PATENTED (bottom) r-e/emb 919,386 Cook Pottery Co. Probably made before R-10 and R-129; patent 919,386
R-72

WES co / 5 1/2 / U emb     1-1/8" diameter
R-65

W P CO emb   Wisconsin Porcelain Co. 1-3/16" diameter
R-111 (don't have) WP 5 1/2 / UL r-e   Wisconsin Porcelain Co. concentric ribbed cap
R-91 WS / U S emb     1-1/8" diameter, unglazed
R-04 W. T. CO. PAT'D JULY 23 1919 emb 1,311,483 Wheeling Tile Co. radially ribbed cap
R-64 W. T. CO. PAT'D APR 26 1921 emb 1,376,307 Wheeling Tile Co. 1-3/16" diameter; radially ribbed cap
    Round Split Knobs, Oval Split Knobs, Round Reversible Split Knobs        
R-61

R-61.jpg (12899 bytes)

50 emb   Davidson Porcelain Co. 1-1/2" diameter
R-60

R-60.jpg (14851 bytes)

BRUNT emb   Brunt Porcelain Co. 2" diameter
R-46 R-46.jpg (19301 bytes) R-46_GE.jpg (17290 bytes)

R-46_btom.jpg (18986 bytes)

G. E. KNOB // E P emb / r-e   General Electric Co. 1-1/2" diameter
R-20 R-20.jpg (16853 bytes) R-20_F.jpg (17021 bytes)

R-20_btm.jpg (19068 bytes)

F // F emb 464,770 Findlay Electric Porcelain Co. 1-3/8" diameter, caming groove
R-21 R-21.jpg (17249 bytes) R-21_GE.jpg (17793 bytes)

R-21_btm.jpg (18857 bytes)

G. E. KNOB / PAT APLD FOR // 9352 emb   General Electric Co. 1-1/2" diameter
R-22 R-22.jpg (20011 bytes) R-22_GE.jpg (22294 bytes)

R-22_btm.jpg (25178 bytes) R-22_open.jpg (30654 bytes)

G. E. KNOB // CAT. 6580 r-e   General Electric Co. 2" diameter
R-25 R-25.jpg (21335 bytes) R-25_GE.jpg (18940 bytes)

R-25_btm.jpg (23322 bytes)

G. E. KNOB // CAT. 6580 emb   General Electric Co. 2" diameter
R-47 R-47.jpg (18658 bytes) R-47_GE.jpg (17654 bytes)

R-47_btm.jpg (20180 bytes)

D. P. CO // 9419 emb / r-e   Davidson Porcelain Co. 1-1/2" diameter
R-23 R-23.jpg (21934 bytes) R-23_PPInc.jpg (20810 bytes) P. P. Inc. emb     2" diameter; matching vertical groove on the side
R-24 R-24.jpg (20382 bytes) R-24_PPInc.jpg (21644 bytes)

R-24_btm.jpg (27636 bytes)

P. P. Inc. / 9420 // P. P. Inc. / 9420 emb     2" diameter; matching vertical groove on the side
O-01

N-N     Colonial Sign & Insulator Co. similar to patent 806,588
O-03

STAR // (embossed star) PAT DEC 5 05 r-e / emb 806,588 Star Porcelain Co.  
O-04 O-4.jpg (15569 bytes) O-4a.jpg (22966 bytes)

 

(embossed star) // (r-e star) PAT APLD FOR emb / R-E 806,588 Star Porcelain Co.  
O-02

T / PAT / 4803 / NO. 5 emb 697,001 R. Thomas & Sons Co. reversible, oval; error date, should be 4-8-02
RR-01

.G. PAT APPD FOR (circle) emb     1-1/8" diameter; reversible
RR-09 RR-09_B-D.jpg (28844 bytes) RR-09_B-D_top.jpg (34904 bytes) B&D PAT. / AUG. 13, 95 emb 544,501 Buffinton & Dow patent (licensed) 1-1/2" diameter; reversible; cleat patent
RR-02 BUCKEYE REGD (circle) PATD 12-31-12 / F (outer circle) emb 1,048,850 Findlay Electric Porcelain Co. reversible, crossover knob
RR-06 F / PATD / 12-31 / 12 (in circle) emb 1,048,850 Findlay Electric Porcelain Co. 1-1/8" diameter; reversible
RR-07 RR-07.jpg (16380 bytes) RR-07_F.jpg (16915 bytes) F / PATD / 12-31 / 12 (in circle) emb 1,048,850 Findlay Electric Porcelain Co. 1-1/4" diameter; reversible, crossover knob; error date 12-13 instead of 12-31
RR-10 RR-10.jpg (29800 bytes) RR-10a.jpg (33739 bytes) O. P. / CO. / NO. 1 // PAT. / APR. 8 03 emb 697,001 Ohio Porcelain Co. 1-3/8" diameter; reversible
RR-05 PAT. / APP.D. / FOR / G. (in circle, G inside circle) emb     1-1/8" diameter; reversible
RR-11 RR-11.jpg (18471 bytes) RR-11a.jpg (22555 bytes) PATD / 24 / 085 / 1611 (circle) emb 992,570   1-1/8" diameter; reversible
RR-04 T / PATD 7-20 / 1915 emb 1,147,498 Trenton Porcelain Co. 1-1/8" diameter; reversible
RR-03 T P I / NO 1 / T / PAT / APR / 803 emb 697,001 R. Thomas & Sons Co. 1-3/8" diameter, reversible, error date, should be 4-8-02
RR-08 RR-08.jpg (18943 bytes) RR-08_Thomas.jpg (21798 bytes) T P I / NO 2 / THOMAS / PAT / APR / 8 03 emb 697,001 R. Thomas & Sons Co. 1-3/4" diameter; reversible
    Square Reversible Split Knobs, Misc. Knobs, and Square Knobs        
SR-01 U S / PATD / 2408 / 51611 emb 878,302 US Electric Porcelain Co. reversible
SR-02 Triangle M / PAT'D / FEB 9 / 1915 emb 1,127,776 Illinois Electric Porcelain Co. reversible
SR-03 U S / PAT'D (on short end) emb 878,302 US Electric Porcelain Co. reversible
SR-04 U S / PAT'D (on long end) emb 878,302 US Electric Porcelain Co. reversible
SR-05   O P / CO emb 878,302 Ohio Porcelain Co. reversible
S-03

MACOMB. / PAT. / MAR-1-04 // S-H. co. / No. 1. r-e 753,399 Illinois Electric Porcelain Co. Snyder-Hunt Co.
S-04

S H co. / no 1. // MACOMB. / PAT. / MAR-1-04 r-e 753,399 Illinois Electric Porcelain Co. Snyder-Hunt Co.
S-01

S-H Co. / No. 1 // A. P. C. L. / Pat. / Mar. 1, '04 emb 753,399   Snyder-Hunt Co.
S-02

S-H Co. / No. 1 // MACOMB / PAT / MAR-1-04 r-e 753,399 Illinois Electric Porcelain Co. Snyder-Hunt Co.
S-05 S-05.jpg (25105 bytes) S-05_Klingel2.jpg (30151 bytes) Triangle M / PARALLEL / KNOB / PAT. APPL. FOR // E. L. KLINGEL / ST. PAUL emb / r-e 2,307,277 Illinois Electric Porcelain Co.  

 

Nail Knobs page:    

R=∞ Home