Machine Drawing

Limits, Tolerances and Fits 239

dharm
d:\N-Design\Des15-2.pm5

15.6 Compute the limit dimensions for a clearance fit on the hole basis system, for a basic size of

40 mm diameter, with a minimum clearance of 0.05 mm; with the tolerance on the hole being

0.021 and the tolerance on the shaft being 0.15 mm.

15.7 Find the limit dimensions for an interference fit on the shaft basis system for the above problem

and compare the dimensions of the shaft and hole.

15.8 Determine the type of fit and calculate the clearance and or interference for the schematic toler-

ance zones shown in Fig. 15.21.

–36

–50

(c)

–23

0

+18

0 0

+10

–12

–8

–23 –25

(a) (b)

Hole

Shaft

Fig. 15.21

15.9 Suggest suitable fits and their letter and tolerance grades for the components shown in Fig. 15.22.

D

F

E

C

GG

AA

BB

A – Shaft rotating in bush

B – Bush fixed in housing

C – Bush is secured on to the gear

D – Base plate of the gear unit is secured on to the

casting by cylindrical pin

E – Gear with the bush rotating on to the pin

F – Pin is secured on to the base plate

G – Bush with plate

Fig. 15.22