THE INDIA RUBBER WORLD 



[Skiteme 



Material. — See General Specifications. 



(a) Fabric shall weigh not less than 12 ounces per square 

 yard. 



(fr) The rubber compound shall contain not less than 40 per 

 cent of fine Para ; not more than 3 1/2 per cent sulphur ; remainder 

 to be suitable dry inorganic mineral fillers. 

 Inspection. — See General Specilicatioiis. 

 Tests. — See General Specifications, 

 (a) Fabric: 



Tensile, minimum- — 



Warp 1 25 pounds. 



Filling 125 pounds. 



Yards per inch each, warp and filling 22, plus or minus 4. 



(i>) Friction, minimum 14 pounds. 



(c) Tensile rubber layers, minimum 1,800 pounds. 



(rf) Ultimate elongation, minimum 2 to 11 inches. 



(<■) IVrmanent set— ^ o ■ h 



CLOTH INSERTION RUBBER PACKINa 



War Department Specification, No. 838-2-1— June 5, 1919. 



(Al-THORITY OF SuPPI.V CIRCULAR No. 8, P. S. & T. DlV., JaNU.\RY 24, 1919.) 



General.— (a) This specification covers requirements for 

 grade I packing used in flanges of ventilation systems or in 

 flanges in contact vi'ith cold water which are separated only at 

 long intervals ; grade II packing used in flanges in contact with 

 cold water which are separated frequently. 



(b) See War Department Specification No. 333-1-1, headed 

 General Specification for Mechanical Rubber Goods", which is 

 made a part hereof, except in such cases as the provisions below 

 directly conflict. In such cases the word and meaning of this 

 specification will govern. 



Construction. — See General Specifications. 



(a) To consist of alternate layers of rubber and cotton sheet- 

 ing or a plain weave fabric in such a manner that both faces of 

 packing shall be of rubber. 



(6) Made about 36 inches wide, and in rolls weighing approxi- 

 mately 125 pounds, unless otherwise specified. 



(c) Cotton insertion shall be properly frictioned with a com- 

 position to meet required tests. 



(rf) For every 1/16-inch thickness there shall be at least one 

 ply of cotton sheeting or a plain weave fabric. 



(e) 1/32-inch packing shall have only one ply of insertion and 

 shall be furnished in grade II only. Grade I shall be furnished 

 in thickness 1/16-inch and above. 



Branding. — See General Specifications. 



(o) Use the words "Water, Grade I" or "Water, Grade II," 

 as specified in proposal. 



]\1ateri.\ls. — See General Specifications. 



(a) Fabric to weigh not less than 4.75 ounces nor more than 

 5. IS ounces per square yard, count to be 35 to SO threads per 

 inch for both warp and filling directions. 



(b) All rubber layers to be of the same composition. 

 Inspection. — See General Specifications. 



Tests. — See General Specifications. 



(a) Grade I : 



Friction adhesion between rubber layers and fabric insertions, 



minimum pounds 7 



Tensile of rubber layers, minimum 1,000 



Ultimate elongation, minimum inches 2-11 



Permanent set: 



•Stretch for 10 minutes, minimum 2.10 



Set after 10 minutes' rest, maximum per cent 20 



(b) Grade II. — One-sixteenth-inch complete packing shall 

 weigh not less than five or more than six pounds per square 

 yard, and other thicknesses in same proportion. Packing weigh- 

 ing over six pounds per square yard may be rejected, or accepted 

 with payments based on area corresponding to 6 pounds per 

 square yard. 



Shall be pliable enough to stand bending double in any direc- 

 tion without cracking. 



A 4-inch square of packing shall be placed in the water of an 

 autoclave. Another section shall be placed on flange of auto- 

 clave with steel plate clamped on so as to cover the entire pieces 

 of packing. The autoclave shall be heated to give an internal 

 steam pressure of SO pounds per square inch for four hours. 

 Both sections shall be allowed to rest one hour after removing 

 from autoclave, after which they shall show no blisters or other 

 apparent injury. Packing under 1/8-inch thick shall not crack 

 when bent double; packing 1/8-inch and over in thickness shall 

 not crack when bent around 1/4-inch round mandrel. 



RUBBER VALVES. 



War Department Specification, No. 335.1-2— June 5, 1919. 

 (Authority of Supply Circular No. 8. P .S & T. Div.. Janu.^ry 24, 1919.) 

 General. — (o) This specification covers the requirements for 

 valves used in pumps, condensers, etc. 



=?ee The India Rubbkr World. January 1, 1920, page 214. 



(b) See War Department Specification No. 333-1-1, headed 

 General Specification for Mechanical Rubber Goods', which is 

 made a part hereof, except in such cases as the provisions below 

 directly conflict. In such cases the word and meaning of this 

 specification will govern. 



Construction. — See General Specifications. 



(a) The valve surfaces shall be smooth and free from pitting, 

 air checks, other imperfections, and properly finished. They 

 shall be hard, medium, and soft, as required. 



Branding. — See (ieneral Specifications. 



(o) Valves shall be molded with the words "U. S. A.," 

 "Hard." "Medium." or "Soft," manufacturer's name, and date 

 on edge of valve. 



Material. — See General Specifications. 



(o) Valves shall be made from a compound containing fine 

 Para rubber, sulphur, and suitable dry inorganic fillers, as speci- 

 fied in table below : 



Minimum Specific gravity. 



percentage Total , ^-- ^ 



fine Para, sulphur. Minimum. Maximum. 



Hard 30 10 1.7 1.9 



-Medium 35 5 1.4 1.8 



Soft 35 2.5 1.6 1.8 



Inspection. — See General Specifications. 



(a) Inspector shall select one valve from every lot for tests. 



Tests. — See General Specifications. 



(a) Half a valve taken at random from the lot shall stand 

 a dry-heat test 270 degrees F. for one hour; the other half from 

 same valve shall stand a dry saturated steam test of 400 degrees 

 F. for three hours. The valves shall not disintegrate nor blister 

 in either of the above tests. 



SOLIDS PLUS PNEUMATICS. 



Commenting on a caption of frequent occurrence in motor 

 papers, F. R. Fageol, of the Fageol Motors Co., Oakland, Cali- 

 fornia, asserts in "Automotive Industries" that it should read 

 "Solids Plus Pneumatics" rather than "Solids vs. Pneumatics." 

 Pointing out that both types of tires have their own peculiar 

 functions, and that both are undoubtedly here to stay, he very 

 aptly asserts that pneumatic tires will not run solids out of busi- 

 ness, but will simply run trucks into more business. At present 

 and apparently for some time to come pneumatics can no more 

 displace solids than can trains displace boats. 



From the truck manufacturer's point of view, pneumatics 

 merely extend the range of truck transportation beyond the field 

 developed on solids. Most tire manufacturers produce both 

 types. Thus there are occasions for comparison, but very little 

 conflict. 



For slow-moving heavy loads in congested traffic, it is hard 

 to conceive anything more satisfactory than the solid rubber truck 

 tire, but it will not withstand long continuous use at high speed 

 as do pneumatics. In the past there was no need of speed in 

 trucking, and neither trucks nor roads were built for it. With 

 lagging transportation facilities now the most serious problem 

 before the world, however, the efficiency of all known trans- 

 portation agencies must be increased, and neither truck load nor 

 road will withstand the shocks and vibration of high speed 

 unless cushioned by pneumatics. 



Roads are being built to meet present-day needs, and pneu- 

 matic cord tires have enabled truck manufacturers to develop 

 transmissions and other improvements to increase speed and 

 economical hauling radius. The modern seven-speed truck trans- 

 mission, for example, gives an over-drive for speed of thirty 

 miles an hour on the open road, together with an extremely low 

 reduction for steej) grades on unusually heavy going. Pneumatic 

 tires also aff'ord traction under certain unfavorable conditions 

 that render truck operation on solids very difficult. Sand, loose 

 dirt, and mud seem to hold no terrors for the pneumatic. 



Many claims of savings in operation costs, such as fuel con- 

 sumption and general repairs when pneumatics replace solids, are 

 being made, but these are entirely beside the point. Pneumatics 

 do increase the usefulness of the motor truck and that is the real 

 issue. They do not supplant solids, but bring into truck range 

 an entirely new class of business heretofore necessarily handled 

 by some less satisfactory means. 



