For $\backslash$phi $20$mm D$(7)/($h$)6$ hole shaft combination:

a$.$ Calculate the limits of sizes and identify the fit.

b$.$ Explain Taylor's principle of gaging. Plug gages $($Go and No$-$go$)$ are required to control

the production of $\backslash$phi $20$mm D$7$ hole as per IS specification. The tolerances required in

the gage and additional wear tolerances are shown in Table $1.$ Will you provide wear

tolerance on both go and no$-$go gages or on the one which wears more? Which gage is

expected to wear more and why? Find suitable dimensions of plug and ring go and no$-$

go gages for both hole and shaft.

Given: Fundamental deviation of D hole, EI$=+16$D$^(0\mathrm{.}44),$IT$7=16$i; and h shaft, es $=0,$IT$6=10$i$.$

Diameter range is $18-30$mm$.$ Fundamental tolerance unit i$=0\mathrm{.}45\backslash$root$(3)($D$)+0\mathrm{.}001$D

Table $1$: Chart of gage and wear tolerance for given work $($hol$($e$)/($s$)$haft$)$ tolerance