THE INDIA RUBBER WORLD 



189 



(e) Strength of the union between sidewall and plies shall average 14 

 pounds or more per inch, using the standard dead weight friction test as 

 above provided. 



(1) Strength of the union between cushion and plies shall average 16 

 pounds or more per inch, using the standard dead weight friction test as 

 above provided. 



5 Road Test. Manufacturers bidding on government requirements must 

 meet the following conditions: 



(a) Casings will not be given consideration unless the maker submitting 

 the bid furnishes an affidavit stating that he has maintained and will 

 continue to maintain at least two cars used exclusively for test work, and 

 that these cars average at least SOO car miles per car per week. 



(b) The speeds, loads (which may be of merchandise), tire sizes, infla- 

 tions and road conditions must be such that the casings are properly tested. 

 The Government may appoint an inspector to see that the above conditions 

 are complied with. 



(c) A bidder must supply an affidavit before delivering any casings to 

 the Government, stating that the casings to be delivered are the same cross- 

 section and practically duplicate, in construction and material, casings which 

 he has previously tested in accordance with paragraphs (a) and (b), and 

 a sufficient number of casings satisfactory to the Government, not less 

 than four, have averaged on the rear wheels at least 5,000 miles. 



6. Lining. The inside of each casing shall be properly lined in accord- 

 ance with the standard practice of tire manufacturer. 



7 Flaps. A flap shall be furnished with each casing, as in standard 

 commercial practice. 



8. Compounds, (a) Tread. — The tread shall be made from and have 

 the characteristics of a compound containing at least 70 per cent by volume 

 of the best quality new wild or plantation rubber. The minimum tensile 

 strength shall be 2,400 pounds to the square inch, with a minimum elonga- 

 tion of 500 per cent (2 to 12 inches) as determined by the average of four 

 test pieces when stretched at the rale of 20 inches per minute. The test 

 pieces shall be cut longituditially and shall be ^-inch wide over a gage 

 length of two inches, the ends being gradually enlarged to a width of ap- 

 proximately one inch. The permanent set determined by the average of 

 four tests with test pieces a^ above, shall not exceed 25 per cent after an 

 elongation of -100 per cent (2 to 10 inches) for ten minutes, followed by 

 a rest of ten minutes. AH tests shall be made at a temperature between 65 

 and 90 degrees F. 



(b) Friction aiid Cushion.— These shall be made from and have the 

 characteristicts of a compound containing at least 85 per cent by volume 

 of the best quality new wild or plantation rubber. 



(c) Sidewall. — The sidewall shall be made from and have the character- 

 istics of a compound containing a minimum of 65 per cent by volume of 

 the best quality new wild or plantation rubber. The compound shall have 

 a minimum tensile strength of 1,500 pounds per square inch and a minimum 

 elongation of 450 per cent (2 to 11 inches). The permanent set shall not 

 exceed a maximum of 25 per cent, tested as specified in B(a). 



(d) All above test pieces must be cut from casings., 



(e) The above compounds shall be free of ingredients known to the 

 rubber trade as oil substitutes and/or reclaimed rubber. 



9 Inspection. The Government reserves the right to make any inspec- 

 tion, test or analysis necessary to insure the product meeting all require- 



""To'^ °WRAPPiNcf " n" Marking. . All casings shall be spirally wrapped ac- 

 cording to standard practice and properly labeled on the outside showing 

 the sizi and type, and name of manufacturer. A label with the mon h and 

 vear of manufacture stamped on it shall be pasted m a conspicuous place. 



11. Packing. Packing shall be as per specifications accompanying the 

 request for bid. 



SOLID MOTOR TIRES. 

 Specification No. 1074A. 



November 1. 1918. 



1. Type. The t 

 with the standard ^.ia....v.. — ^^ „.^-.. „. ..-~ - . . i 



suitable for pressing on to S. A. E. standard felloe bands for co,nme,v;,a. 

 sized wheels or bands built to S. A. E. tolerance for artil ery vheels. 



2 RuBiiER. The rubber compound shall contain not less than, 65 per 

 ceni by volume of best quality new wild or plantation rubber If reclamed 

 rubber nr mineral rubber is used, it must be in addition to the 65 per 



of 



ubber rcquii 



formula. The use of "refined" 

 pounds will not be permitted. 



3. Sulphur. The total sulph 

 the weight of thi 



and the 

 rubber c 



ufact' 

 rubber : 

 vulcanized 



bstil 



ubber 



decla 

 jsed i 

 ,n the 



the 



of 



shall not be m.ore than 8 per cei 

 „ except as follows; if the manufacturer 

 desires to use sulphur-bearing fillers, thereby causing the total sulphur to 

 be over 8 per cent of the weight of new rubber, he may do so, but shall 

 submit for analysis a sample of the finished unvulcanized stock. Such 

 stock shall not sho\y a sulphur content in the acetone extract of over 8 



'"4. "saponifiable Matter. The rubber compound shall be free from 

 saponifiable oils, or anything made from them. , „ u j 



5 Chfmic/l Tests. Where chemical tests are used, they shall be made 

 in accordance with the Bureau of Standards methods. 



6. Tensile Strength. The average tensile strength of rubber com- 

 pound shall not be less than 1.800 pounds per square inch if the specific 

 gravity is 1.40 or over. If the specific gravity is ,-- ' 

 mum tensile strength shall be 2,000 pounds per squ 

 sftall be cut from each tire under test; the sampi 

 manner as to give the proper shape of testing str 

 stretch and set. The center of test sample sha - ., . . 



"nch long. The samples shall be kept in the testing 



' 'rom 65 to 90 degrees F. 

 The average shall be taken on not less than five samples. Pieces obviously 

 defective will 



7. Stsetc: 



40 the 



Five samples 



'sting oT th? 



ch thick by 



shall be kept in the t 



of from 65 to. 90 degrt 



sidered in calculating the average result. 

 The one-inch straight length of test piece above referred 



._. length of 4'. 

 the rate of 20 inche; 

 eased length of the ( 

 not more than 40 per 



before breaking. The 



per 



ute. 



Agi 



for 



,ve flat samples of rubber to be tested; place in 

 t a temperature of 228 degrees F. After removing 

 stand for 24 hours and determine elongation. The 

 the breaking point shall be 



from the 



reduction ... ^ -,„.. - „ .- 



10. .^DTIESlON. The adhesion test shall be made : 

 tire horizontally on platen of tire applying press, the 



above the lower platen of the press on a steel band having tne same 

 the base of the tire to be tested. Place on the upper side of 



ongatio 



:r 35 per cent, 

 iws: (a) place 

 being supported 



1}^ inches larger than 

 :rs of the band to be 

 rounded with Ji-inch radius. The various sizes of tires are to be submitted 

 respectively to pressures in accordance with the following table. For the tire 

 to pass successfully, the hard rubber must not break loose from the base. 



(a) 



ires 



bid furnishes an affidavit 

 to maintain at least one t 

 truck averages at least 5( 



(b) The speeds, lire 

 road conditions must be 

 Government may appoint 

 complied with. 



turers bidding on government requirements 



n consideration unless maker submitting the 

 ng that he has maintained and will continue 

 used exclusively for test work, and that this 

 uck miles per week. 



;, loads (which may be merchandise), and 

 h that the tires are oroperly tested. The 

 nspector to see that the above conditions are 



■idder must supply an affidavit before delivering any tires to the 

 t. stating that the tires to be delivered are practically duplicates 

 :tion and material of tires which he has previously tested in 

 with paragraphs (a) and (b), and a sufficient number of tires 

 least four tires, have averaged, on the 



Tests i.n t 

 by the Government as 1 



14. Marking. All 

 rubber, the tire size, i 

 compound or specificatii 



7,000 



larger. 





number, the 



of the manu 



arked. by 



facti 



le side of the tread 

 and also the rubber 

 nber, month and year 





ording 



15. 



ampii 



nber and a symbo. _^ „ 



turer. The above data shall be stamped under the overhai 

 steel channel. In case of artillery tires they shall be m; 

 1 bhie-print submitted. 



ION OF Tires. — Full-sized drawings shall be submitted 

 ng the exact section of the tires which it is propose 



vith 



proposals 



furnish. Sample section of the actual tire in each size shall' _. 



submitted. 



16. Weights and Akeas. The total weight of tire, weight of rubber 

 weight of steel base band, together with the total sectional area of tread 

 also the area of tread rubber above the tops of steel 

 in proposals, and this data will be given 



channels must be definitely sta 

 due consideration in connection 



17. Grooving of Tires.— Tire 10 inches 

 provided with approved grooving on face of 



18. Guarantee. The manufacturer of tin 

 free from defects in material and workman 



19. Base Band.— The tire base shall he n 

 rolled to approximate finished 



■idth 



itted. 



follows 

 phosphorous less tl 



Base bands are to be electr 



and free from appreciable war 



Dimensions of Base Bani 



of tires of standard S. A. E. 



standard practic 



nd larger shall be 



res must guarantee them to be 

 nship. 



made of open hearth steel and 



Chemical analysis shall be as 



ed; manganese, 0.35 to 0.55; 



rally welded. They shall be truly circular 



s. The inside circumference of base bands 

 commercial sizes shall be in accordance with 

 ufacturers, but manufacturer must guarantee 

 shall not come off when applied to standard S. A. E. wheels. Tires 

 made for artillery wheels shall have the inside circumference of base bands 

 made in accordance with dimensions and tolerance given on Ordnance De- 

 partment drawings. 



To determine the effectiveness of the welding process used pieces of base 

 band metal not less than 8 inches in length will be welded together and 

 turned down to a standard specimen and three such samples containing 

 welds pulled in a testing machine. The total pull required to separate 

 each of the three welds shall be more than 45,000 pounds per square inch 



being properly welded 



In order to determine whether the base bands 



in production, the inspector may, from time to .,., _ „.. 



the finished tii es to be tested in tlie manner described above. The strength 

 of the welds in production shall be not less than 45,000 pounds per square 

 inch of the section as tested above. 



20. Prfparatiox for Shipment, (a) Painting.— Paint metal bases 

 with rust-resisting paint. 



(b) Wrapping. — Xo wrapping required. 



(c) Marking. — Shipping instructions to be shown on printed label pasted 



