628 



THE INDIA RUBBER WORLD 



[August 1, 1919. 



The IciiKtli of ihe aail rather than the gage of the wire is the the nialcrial of ihe board is made thinner. This may be obviated 



principal factor in its holding power, and as nails split the wood 

 it is desirable to use as small a gage as can be driven in nailing 

 machines. Nails should be driven flush with the wood, and 

 never be overdriven, as this often causes the heads to break the 

 fiber of the wood under the heads, leaving no holding power 

 in the wood. The evil effects of overdriving nails increases as 



measure by greater care in driving the nails 

 Six-penny nails and smaller should be spaced not more than 

 two inches apart when driven in the side grain of the end and 

 not more than 1J4 inches when driven in the end grain. The 

 spacing of nails in end construction should be increased from 

 the above, 'A inch for each penny over si.x. 



American Society for Testing Materials. 



Reports of Committee D-11 ou Rubber Products and Committee D-13 on Rubber Textiles. 



AT THE ANNU.M. JiEETiNG of the .\merican Society for Test- 

 ing Materials held in Atlantic City, New Jersey, June 

 24-27, reports were made by Committee D-11 on rubber 

 belting, hose for pneumatic tools, and insulating tape, and by 

 Committee D-13 on the rate of gain in tensile strength due to 

 moistened absorption in rubber textiles. The proposed revisions 

 of the tentative specifications follow : 



PROPOSED REVISION OF TENTATIVE SPECIFICATIONS FOR 



RUBBER BELTING FOR POWER TRANSMISSION 



(D 53-18 T.).' 



The committee recommends that the following revisions be 



made in these specifications, and the specifications as revised 



continued as tentative: 



1. Section 8.— Change the length of sample of belting submitted for 

 inspection from 36 to 30 inches. 



2. Add new Section 10 as follows: 



10. The filler or weft strength of the cotton duck in the belting shall 

 be determined as follows: A transverse strip I'/i inches wide shall be cut 

 from the belting and opened up into its various plies. Each of these 

 plies shall be ravelled down to a width of 1 inch and tested in a fabric- 

 testing machine, the minimum width of jaws of which is 1^ inches, the 

 distance between jaws, 3 inches, and the speed of separation of jaws, 

 20 inches per minute. The tensile strength shall be at least 175 pounds. 



3. Change present Section 10 to Section 11, and change the length of 

 specimens submitted for inspection from 36 to 30 inches. 



4. Change present Section II to Section 12 and reword Paragraph (o) 

 as follows: 



(a) The friction test or adhesion between the plies shall be conducted 

 in the following manner: Test specimens, each 1 inch in width, two 

 ;,i;.. ;„ thickness and at least 4 inches in length, shall be prepared in 

 .. .■ These should 



adhesio 



sufficient numbi 



be taken transversely for belting 4 



tudinallv for lesser widths. The 1 



tance o'f about 1 ."S inches and bj 



test specinien shall be mounted 



of jaws and the lower pulling pa 



pounds. The rate of separation 



than 1 inch per minute. 



Omit present paragraphs (b) and 



follows: 



(b) A suitable fricti< 

 to make the above test, 

 ping of 1 inch per mini 

 5. Change present Section 12 to Sectio 



(e) as follows: 



(e) The elongation at the breaking load 

 2-inch gage length of the test specim- 

 not less than 9 inci ■ ' ' 



between all plit 

 les and over in width, and 

 alies shall be separated for 

 ans of these separated end: 

 ly between the upper fi.xed 



testing machine where availab 

 which case the pull required 

 shall be not less than 18 poui 



13. 



eword Paragraph 



id shall be 



I for the 



d for the beading to not 



LEADER HOSE FOR USE WITH PNEUMATIC TOOLS, 



h that the original 

 sr shall stretch to 

 : than 10 inches. 



1. (a) These specifications cove 

 ut more than 125 pounds pressure, 

 (b) The hose is of two classes: 

 (-■\) Braided leader hose has a 



D— 19T. Is 

 leader hose for air 



1919. 



ose has a reinforcement 

 in yarn Detween me inner tube and the oute 

 3) Wrapped leader hose has a reinforcemer 

 between the inner rubber tube and the outer 



of three pli. 

 rubber cover 



tools working at 

 f braided 



ooth, uniform in quality, and 



3. The inner rubber tube shall be 

 thickness and free from injurious defects 



4 (a) The reinforcement of braided leader hose shall 

 plies ot cotton braided layers evenly and firmly _ 

 Each layer shall be well impregn 

 ' OiT'Th" relhforc^ement of wrapped leader hose shall consis 

 canva' cut on a 45-degree bias and applied evenly and firmly ov 

 tube. Each ply shall be well frictioned i 



rubber compound 



both side 



:) The 



free 



lightly defects, 



mer tube, 

 litable for 



ubber com- 

 dirt, knots. 



(b) The reinforcement shall be sufficiently strong to enable the 

 iiiL'SsfuUy withstand the hydrostatic pressure test, yet at the same 

 jft and pliable. 



5. The rubber cover shall be uniform in quality and thickness, 

 rom injurious defects. 



6. When specified, the hose shall be given an extra covering < 

 f half-round galvanized steel wire 7/32 by 3/64-inch, wrapped witl 

 jace between adjacent wires. 



hose to 

 time be 



nd free 



n. PHYSICAL PROPERTIES AND TESTS. 



applicable, references are made below to the Standard .Methods 

 Cottoti Rubber- Lined Hose (Scnal Designation; D 15b) 



. When 

 Testing 



Society for Test: 



8. Tile temperature of testing room and samples shall be as defined 

 in Section 19 of Standard Methods D 15. 



9. Piior to the hydrostatic test specified in Section 12 (b), a sec- 

 tion of hose 16 inches long shall be cut at any place from each test length 

 and subjected to the following tests: 



10. The adhesive quality of the rubber impregnation binding the plies 

 together shall be determined in the case of braided leader hose by sus- 

 pending a 20-pound weight from the separated end of a ply having a 1- 

 inch section, cut longitudinally from the 16-inch sample described in Sec- 



20-pound 

 ut from tl 



vrapped leader 

 :ight from the 

 16-inch samph 



hose it shall be determined by suspend- 

 5eparated end of the duck of a 1-inch 

 described in Section 9, the force being 



shall 



be greater 



In both cases the rate of separation of the 

 than 1 inch per minute. 



11. (a) The tests of tube and cover shall be conducted in accordance 

 with Sections 18, 19, 20, 22, 23, 24 and 25 of the Standard Methods D 15. 



(b) Test specimen shall be cut longitudinally of the hose. 



(c) When stretched from 2 inches (the original gage length) to 9 inches, 

 the stress in the specimen from the tube shall be at least 1,000 pounds 

 per square inch, and in that from the cover at least 800 pounds per 

 square inch. 



(d) The set, or permanent elongation following a stretch from 2 inches 

 to ',/ inches, shall not exceed 25 per cent. 



(e) The tensile strength shall be not less than 1,500 pounds per square 

 inch for the tube, and 1,300 pounds per square inch for the cover. 



(fl The elongation at the breaking load shall be such that the original 

 2-inch gage length of the test specimens for both the tube and cover shall 

 stretch to not less than 11 inches. • 



l^. (a) The method of conducting the hydrostatic pressure tests shall 

 be in accordance with Section 26 of Standard Methods D 15. 



(b) Each length of hr.se shall be subjected to a proof pr 



250 pounds per 

 armored hose tl 

 (c) From t t 

 shall be furtli, 

 inch for 10 mu 





lutes to expose imperfections. On 

 made after the removal of the armoring, 

 isths or less of hose inspected, one length 

 i pressure test of 800 pounds per square 

 shall withstand -without bursting, (^n large 

 y be reduced to not less than three at the 

 :iting the purchaser. 



13. Unless o 

 foot lengths, whi 

 length shall be u 



14. (a) The i 



shall 



\NDABD DI>. 



specified. 



7/16 



(b) The gage 



bedded in the r 



pped and without 

 imum tube and cover thickr 

 er of Minimum Tube 



Thickness, Inch. 

 3/32 

 ot tube and cover shall be n 

 ubber. 



i hose shall be furnish 

 e than 4 pounds. The en 



tings. 



Each length of hose shall have inlai< 

 ds. a brand showing the name of the 

 f manufacture, the trade-name of the 

 . A.S.T.M'. Specifications," 



and the 



16. 



The 



of the 



(b) The manufacturer 

 chaser, without charge, 

 hose is being furnished 

 and inspections shall be 



V. INSPECTION 



nufacturer shall 

 pletion of the ho 



shall afl'ord tb 



or representing the pur- 

 facilities to satisfy him that the 

 ith these specifications. The tests 

 ace of manufacture prior to ship- 



(c) Th 



irchaser may make the tests to govern t 

 1 of the hose in his own laboratory or elscwher 

 shall be made at the expense of the purch.nser. 



.Samples of rejected hose shall be preserved for 



' ' test report. 



the 



nufacturer may 



sfactii 

 :iety for Testing Ma 



weeks from the 

 e results of the 

 lin that time. 



