BS 1916-1:2009 pdf free download – Limits and fits for engineering Part 1: Guide to limits and tolerances.
The method of determining the fundamental deviations 1) for the various fits as used in the inch conversion is given in Table B.1.
The fundamental deviations of the holes “A” to “G” are identical with those of the shafts “a” to “g” but of opposite sign.
In the case of limits “a” to “h” and “A” to “H”, the formulae give the upper limits of tolerance of shafts and the lower limits of tolerance of holes. In the case of limits “k” to “z” and “K” to “Z”, the formulae give the lower limits of tolerance of shafts and the upper limits of tolerance of holes.
NOTE 1 All tolerances are expressed in units of 0.001 in.
NOTE 2 Diameter D is expressed in inches and is, in all cases, the geometric mean of the diameter steps involved.
c.1 Hole limits of tolerance (Table 2)
a) Hole F9 is envisaged for precision work only up to a diameter of 1.19 in.
b) In the range 0.04 in to 0.24 in, Iimitsfor K6, K7 and K8 do not exist; the limits for J6, J7 and J8 should be used instead.
c) In the range 0.04 in to 0.95 in, limits for T6 and T7 do not exist; the limits for U6 and U7 should be used instead.
d) In the range 0.04 in to 0.56 in, limits for V6 and V7 do not exist; the limits for X6 and X7 should be used instead.
e) In the range 0.04 in to 0.71 in, limits for Y7 do not exist; the limits for Z7 should be used instead.
f) The holes “V”1 “X”, “Y” and “Z” should not be considered as definite recommendations but for trial only. The holes “V’1 and
“Y” should be avoided as much as possible.
C.2 Shaft limits of tolerance (Table 3)
a) In the range 0.04 in to 0.24 in, limits for k5, k6, k7 and m7 do not exist; the limits for j5, j6, j7 and n7 should be used instead.
b) In the range 0.04 in to 0.95 in, limits for t5, t6 and t7 do not exist; the limits for u5, u6 and u7 should be used instead.
c) In the range 0.04 in to 0.56 in, limits for v5, v6 and v7 do not exist; the limits for x5, x6 and x7 should be used instead.
d) In the range 0.04 in to 0.71 in, limits for y6 and y7 do not exist; the limits for z6 and z7 should be used instead.
e) The shafts “v”, “x”, “y” and “z” should not be considered as definite recommendations but for trial only. The shafts “v”
and “y” should be avoided as much as possible.