Twentieth century handbook for steam engineers and electricians, with questions and answers; a practical nontechnical treatise .. (1916)
Swingle, Calvin F. (Calvin Franklin), b. 1846 · Chicago, F.J. Drake & company · leaf 405
e from edge to edge, as at A. Then 392 Steam Engineering A—B-^2=the outside lap. For instance, A=8.5 in., B=6.5 in. Then 8.5—6.5=2, and 2 divided by 2=1 in.,which is the lap. The inside lap should also be measuredat this point for convenience, and the measurements pre-served for future reference.… … Fig. 134 difference by 2. For instance, the distance F is 4 in., and 4—3 E is 3 in.; then =.5 in., making the inside lap ^ in. 2To place the valve central, measure the width of theoutside lap each way from the outside edges of the steamports and mark the points on the valve seat with a sharplead…
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