February 1, 1916.1 



THE INDIA RUBBER WORLD 



229 



Proposed S. A. E. Rubber Standards. 



AT the meeting of the Society of Automobile Engineers, held 

 January 5 and 6 in the Engineering Societies' Building, 

 New York '<;ity, the Standards Committee made many 

 recommendations. Those on insulated wire and cable, rubber 

 hose and clamps, industrial truck tires and solid tire diameters, 

 which are of special interest to rubber manufacturers, are print- 

 ed below. 



It should be noted that these recommendations were favorably 

 received and will be voted on for adoption by a letter ballot of 

 the society which will be polled early in March. 



INSULATED WIRE AUD CABLE. 



The following standards for insulated wire and cable to be 

 used on gasolene cars, were formulated : 

 CLASS A— Rl-BBER CO.MPOr;XD INSULATED SECONDARY CABLE. 



The insulation of this cable shall consist of a vulcanized 

 compound of virgin rubber containing not less than 30 per 

 cent by weight of good dry Upriver Para or Hevea rubber 

 which will stand the following tests: 



A test-specimen of rubber compound taken from a cable hav- 

 ing a length of not less than 6 inches shall have marks placed 

 upon it two inches apart. The sample shall then be stretched at 

 the rate of 12 inches per minute until these marks are 6 inches 

 apart: the test-specimen shall then be released within 5 seconds 

 and a measurement taken one minute thereafter, when the 

 distance between these marks shall then not exceed 2^8 inches. 

 The test-specimen shall then be stretched until marks are 9 

 inches apart before rupture. This test shall be made at a 

 temperature of not less than 10 degrees C. or 50 degrees F. 



The ultimate tensile strength of the rubber compound shall not 

 be less than 1,000 pounds per square inch calculated upon the 

 original cross-section of test-specimens before stretching. This 

 test shall be made at a temperature of not less than 10 degrees C. 

 (50 degrees F.). 



Each specimen of rubber insulated cable shall successfully 

 w-ithstand a voltage test of 12.000 A. C. for 5 minutes after 12 

 hours submersion in water and while still immersed. 



After the voltage test, the cable while still immersed shall have 

 an insulation resistance of 2,500 megohms per mile at 15.50 de- 

 grees C. C60 degrees F. ) after one minute electrification. These 

 two tests shall be made in accordance with the standard rules of 

 the A. I. E. E. 



Any one-foot sample of this rubber insulated cable must show 

 a dielectric strength sufficient to resist through 5 minutes the ap- 

 plication of 20.000 volts A. C. This test shall be made as speci- 

 fied in the National Electric Code. 



The following aging test should be made to determine the life 

 of the cable : Take a length of cable, preferably 5 feet, remove 

 insulation from both ends, solder one end of cable to the end of 

 a steel rod of same diameter as outside diameter of cable, wrap 

 the cable tightly around this rod and solder the other end of 

 cable to the rod so that it will retain its tightly wrapped condition. 

 Leave exposed in this condition to the elements. If cable is not 

 properly compounded and properly vulcanized, deterioration 

 effects, such as hardening, l)ecoming brittle and cracking will be- 

 gin to be apparent in from one to three trionths. 



Secondary cable is to be made in two sizes as shown by Table I. 

 The overall diameters are 7 m.m, and 9 m.m. respectively for 

 plain rubber insulation. If a varnished cotton braid is desired 

 the same dimensions are to lie used with the addition of glazed 

 cotton braid approximately 1/64 inch thick, making the overall 

 diameters 5/16 inch and Yi inch respectively. The braid is 

 to be treated with at least two coats of insulating varnish dried 

 separately. 



No 



CLASS R— RUBBER COMPOUND INSULATED PRIMARY CABLE. 

 The insulation of this cable shall consist of a rubber compound 

 and two thicknesses of fabric. The compound is to be evenly ap- 

 plied in thickness as specified in Table II, and must conform to 

 the physical and electrical requirements of the National Electric 

 Code (latest edition). 



The rubber compound to be covered first either with an over- 

 lapping strip of varnished cambric .008 to .010 inch thick, or a 

 cotton braid at least 1/64 inch thick, so saturated as to make 

 it oil and moisture-proof. 



The first fabric is to be covered with an outer braid of strong 

 protective character and at least 1/64 inch thick, preferably ' 

 glazed and treated with at least two coats of insulating varnish 

 dried separately. 



The completed cable shall be capable of withstanding for one 

 minute one thousand volts A. C. applied between the copper 

 conductor and a metal foil wrapped around the outside of in- 

 sulation. The frequency of the test circuit shall be in accordance 

 with the standard rules of the A. I. E. E. 



TABLE II— RUBBER COMPOUND INSULATED PRIMARY CABLE, 



Diam. Circu- Diam. over Thickness 



Cable No. of of No. of lar Carrying over Braid Rubber 



Size Wires Wires Strands Mils Cap. Amp. Wire (Max.) (Min.) 



No. 14 41 .01003 1 4,100 ... .080 .22 1/32" 



No. 12 49 .0113 1 6,208 ... .102 .25 1/32" 



No. 10 49 .0142 1 9,854 ... .128 .27 1/32" 



No. 2 133 .0226 19 67,764 92 .340 .53 3/64" 



No. 1 133 .0254 19 85,466 102 .380 .60 1/16" 



No. 133 .0285 19 107,743 127 .427 65 1/16" 



No. 00 133 .032 19 135,926 150 .480 .71 1/16" 



Stranding — Number 14 to be bunched; numbers 12 and 10 to be bunched 

 or rope lay; numbers 2, 1, 0, 00 to be rope lay. 



RUBBER-HOSE AND CLAMPS. 



Sizes for hose and hose-clamps are submitted (see table) for 

 standardization. They cover hose in all sizes commonly used for 

 water connections and tire-pumps. There is considerable varia- 

 tion in thickness of hose of the same ply, but generally 1/32 

 inch of hose thickness is allowed for the inside rubber lining, 

 1/32 inch for the outside, and 1/16 inch for each ply of fabric. 

 The table was prepared accordingly with the addition of the tol- 

 limits. 



SIZES OF HOSECLAMPS AND HOSE-FITTINGS. 

 Outside diameter of hose and extended inside 



Inside diameter of clamps. Length of 



l)iameler Single-ply Two-ply 



3/16 7/16 'A 



Vi Vi 9,'16 



5/16 9/16 j-^ 



Ji % 11/16 



/. M 13 16 



■M 1 1 I/I6 



1 1^ 1 5,'16 

 VA 1-4 1 9/16 



I'A m 1 13/16 1% 1 15/16 



IVi 2 2 1/16 2'A 2 3/16 1 'i 



2 2'A 2 5/16 2H 2 7/16 I'A 

 2'4 214 2 9/16 2^ 2 11/16 I'A 

 2'A 2H 2 13/16 2H 2 15/16 I'A 



3 3'A 3 5 16 3H 3 7/16 i'A 

 Limits on inside diameter of hose ± 1/64. Limits on thickness of hose 

 not measured at lap) zt 1/64. All dimensions in inches. 



9/16 



H 

 11/16 



)4 



ik 



m 



2'A 

 2H 

 2H 



11/16 



13/16 



3/16 



INDUSTRIAL TRUCK TIRES. 



It is recommended that the standard nominal diameters of in- 

 dustrial truck wheels shall be 10, 16. 20, 22 and 27 inches. On 

 the data sheet with the wheel diameters shall be printed a foot- 

 note indicating the present tire sections recommended by the 

 Association of Railway Electrical Engineers. 

 SOLID TIRE DIAMETERS. 



It is recommended that the 32-incli di.Tinctcr be dropped from 

 the standard list of truck wheel dianiotirs. This is done because 

 it is found that commercial cars with wliecis as small as 32 inches 

 are almost always fitted with pneumatic tires, and 32-inch tires 

 form a very small percentage of the total output of solid tires. 



The 34-inch tire is recommended for inclusion in the list of 

 sizes. There has been considerable demand for the inclusion of 

 this size in the S. A. E. standards, and the recent circulation of 

 a document signed by tire and wheel makers has served to draw 

 out comment and results in this recommendation. 



The data sheet is to be rearranged to indicate that only tires 

 of 34, 36 and 40 inches are S. A. E. Standard, although data on 

 the other sizes is to be printed as a guide for tires of other than 

 standard sizes. 



