A threaded nut of $$M16, $$ $$ISO$$ metric type having $$2$$ $$mm$$ pitch with a pitch diameter of $$14.701$$ $$mm$$ is to be checked for its pitch diameter using two or three numbers of balls or rollers of the following sizes

The dimensional limits on a shaft of $$25h7$$ are

A part shown in the gig is machined to the sizes given below

With $$100\% $$ confidence, the resultant dimension $$W$$ will have the specification

$$3$$ blocks of $${B_1},\,\,{B_2},\,\,{B_3}$$ are to be inserted in a channel of width $$'S'$$ maintaining a minimum gap of width $$T=0.125mm,$$ as shown in fig. For $$P = 18.75 \pm 0.08,\,$$ $$\,Q = 25.00 \pm 0.12,\,$$ $$\,R = 28.125 \pm 0.1$$ and $$S=72.35+X.$$ The tolerance $$' X '$$ is _______________.