Practical engineering drawing and third angle projection, for students in scientific, technical and manual training schools and for ..draughtsmen .. . f 30; -i„ b6lt -d-r- 454. Triangular-threaded screws.— United States Standard.—The proportions devised by Mr. WilliamSellers of Philadelphia have been so generallyadopted as to be known as the United StatesStandard. They are given in the table on the3iA next page. i Fig. 312 shows a section of the Sellers I screw. It is blunt on the thread, and also ati the root. The part 0 j) B which is removedjg from the point may be regarded as filled inat Ns
Practical engineering drawing and third angle projection, for students in scientific, technical and manual training schools and for ..draughtsmen .. . f 30; -i„ b6lt -d-r- 454. Triangular-threaded screws.— United States Standard.—The proportions devised by Mr. WilliamSellers of Philadelphia have been so generallyadopted as to be known as the United StatesStandard. They are given in the table on the3iA next page. i Fig. 312 shows a section of the Sellers I screw. It is blunt on the thread, and also ati the root. The part 0 j) B which is removedjg from the point may be regarded as filled inat Nst. AB being the pitch (P), the widthsop, st, are each one-eighth of P. With N equal to the number of threadsper inch, and D the outside diameter of thescrew or bolt, the value of d — the diameter atthe root—may be obtained from the formulad = D-( ^N).Other proportions are as follows: The pitch is equal +0625 — The depth of thread equals P. For boltsand nuts, whether hexagonal or square, the width across flats, orshortest distance between parallel faces, equals Z), plus one-eighthof an inch for rough or
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Keywords: ., bookcentury1800, bookdecade1890, booksubjec, booksubjectlettering
