MIKI PULLEY Clutch and Brake Standard Hole Drilling Standards

These standard hole drilling standards apply to the 6 mm to 85 mm hole drilling for electromagnetic-activated clutches and brakes (excluding CYT, CSZ, and BSZ) and spring-activated brakes (excluding BXW). However, if the standard clutches and brakes come with holes, they may not match these standards.

Unless otherwise specified, a hole is drilled with a tolerance of H7. However, H8 is used for the hole diameters of 10 mm or less of springactivated brakes. With the exception of tolerance grade H7, the tolerance is determined through discussion. Surface finishing is not performed for the additional drilled hole based on the prepared hole. If surface finishing is required for the additional drilled hole, please contact Miki Pulley. The following shows the shaft tolerances under various load conditions.

Load condition	Shaft tolerance	Remark
Shaft with ø10 or below	h6 h7	h5 if accuracy is required
Light and normal load and variable load	h6 js6 js7 j6 j7	h6 for motor shaft j6 for clutch and brake unit
Heavy load and impact load	k6 k7 m6

Keyway Sizes for Hole Diameters (Table Below)

In Compliance with the Old JIS Standards (Class 2) Unit [mm]

Hole diameter	b2		t2		Key size b×h
	Standard size	Tolerance(E9)	Standard size	Tolerance
10 or more and 13 or below	4	+0.05 +0.02	1.5	+0.5 0	4×4
Over 13 and 20 or below	5		2.0		5×5
Over 20 and 30 or below	7	+0.061 +0.025	3.0		7×7
Over 30 and 40 or below	10		3.5		10×8
Over 40 and 50 or below	12	+0.075 +0.032			12×8
Over 50 and 60 or below	15		5.0		15×10
Over 60 and 70 or below	18		6.0		18×12
Over 70 and 80 or below	20	+0.092 +0.040			20×13

Models Compliant with
the New JIS Standards Unit [mm]

Hole diameter	b2		t2		Key size b×h
	Standard size	Tolerance(P9)	Standard size	Tolerance
6 or more and 8 or below	2	-0.006 -0.031	0.8	+0.3 0	2×2
Over 8 and 10 or below	3		1.2		3×3
Over 10 and 12 or below	4	-0.012 -0.042	1.5	+0.5 0	4×4
Over 12 and 17 or below	5		2.0		5×5
Over 17 and 22 or below	6		2.5		6×6
Over 22 and 30 or below	8	-0.015 -0.051	3.0		8×7
Over 30 and 38 or below	10				10×8
Over 38 and 44 or below	12	-0.018 -0.061			12×8
Over 44 and 50 or below	14		3.5		14×9
Over 50 and 58 or below	16		4.0		16×10
Over 58 and 65 or below	18				18×11
Over 65 and 75 or below	20	- 0.022 -0.074	4.5		20×12
Over 75 and 85 or below	22		5.0		22×14

Keyway standard size b2	Nominal set screw diameter
4	M4
5	M4
6	M5
7	M6
8	M6
10	M8
12	M8
14	M10
15	M10
16	M10,M12
18	M12,M16
20	M16
22	M16

Hole diameter	Nominal set screw diameter
6 or more and under 10	M3