Holes 1, 2, 3, 4 drilled in sequence, with angular positions

Holes 1, 2, 3, 4 drilled in sequence, with angular positions and tolerances are shown in figure. Evaluate closing angle X with its tolerance band.

X_max = 360 - [79.9 + 10.88 + 109.7] = 60.6
X_min = 360 - [80.1 + 110.2 + 110.3] = 59.4
Clearance = X_max – X_min = 1.2

X_mean =	X_max + X_min	=	60.6 + 59.4
	2		2

X_mean = 60
X = 60 ± 60
when dia is minimum = 59.9mm

(OC)₂ =	59.9/2	= 34.58 mm
	sin 60°

Error in depth = 2[(OC) – (OC)₂] = 0.22 mm.