Accuracy of Spur Gears (Excerpt from Obsolete Standard JIS B 1702:1976)

Single pitch error	The difference between the actual pitch on the pitch circle of adjacent teeth and the correct pitch.
Cumulative pitch error	The maximum cumulative pitch error over the entire gear tooth area.
Profile error	The sum of the positive (+) and negative (-) side errors within the tooth profile testing range (1) measured perpendicular to the correct involute passing through the intersection of the actual tooth profile and the pitch circle (Figure 1). Note that the tooth profile error refers to the tooth profile perpendicular to the axis. Note (1): The tooth profile testing range is, in principle, the range of tooth profile curves that mesh with the mating gear. Note that a tooth profile in the tooth profile repair range is not considered a tooth profile error.
Allowable full engagement of both tooth flanks	The difference between the maximum and minimum center distances when the gear under test makes one complete revolution with both tooth surfaces under test in contact with both parent gear surfaces at the same time.
Tooth space runout	The maximum difference in radial position when a contact piece, such as a ball or pin, is brought into contact with the tooth flanks on both sides of the tooth ridge near the pitch circle.
Total alignment error	The amount of deviation of the actual tooth trace from the theoretical tooth trace, measured in the direction tangential to the base circle at right angles to the axis. The total tooth trace error is the distance between the two theoretical tooth traces on either side of the actual tooth trace.

*All errors are with respect to the centerline of rotation as defined by the shaft, bore or shaft diameter.

Accuracy of Spur Gears: former JIS B 1702:1976 Grade 4 (equivalent to new JIS B 1702-2:1998 Grade 8)

Gear allowable error

Module	Error	Reference diameter (mm)
		5≦d ≦20	20＜d ≦50	50＜d ≦125	125＜d ≦280
0.5	Single pitch error	13	14	15	17
	Cumulative pitch error	32	41	52	69
	Total profile error	13	15	17	20
	Allowable full engagement of both tooth flanks	30	37	46	60
	Allowable tooth space runout	25	32	42	55
0.8	Single pitch error	13	14	15	17
	Cumulative pitch error	32	41	52	69
	Total profile error	13	15	17	20
	Allowable full engagement of both tooth flanks	33	40	49	63
	Allowable tooth space runout	25	32	42	55
1.0	Single pitch error	13	14	15	17
	Cumulative pitch error	32	41	52	69
	Total profile error	13	15	17	20
	Allowable full engagement of both tooth flanks	35	42	52	65
	Allowable tooth space runout	25	32	42	55
1.5	Single pitch error	13	14	15	17
	Cumulative pitch error	32	41	52	69
	Total profile error	13	15	17	20
	Allowable full engagement of both tooth flanks	38	45	55	68
	Allowable tooth space runout	25	32	42	55
2.0	Single pitch error	13	14	15	17
	Cumulative pitch error	32	41	52	69
	Total profile error	13	15	17	20
	Allowable full engagement of both tooth flanks	45	52	61	75
	Allowable tooth space runout	25	32	42	55
2.5	Single pitch error	15	15	17	18
	Cumulative pitch error	33	42	53	70
	Total profile error	19	20	22	25
	Allowable full engagement of both tooth flanks	45	52	61	75
	Allowable tooth space runout	27	34	43	56
3.0	Single pitch error	15	15	17	18
	Cumulative pitch error	33	42	53	70
	Total profile error	19	20	22	25
	Allowable full engagement of both tooth flanks	56	63	72	86
	Allowable tooth space runout	27	34	43	56

Allowable total alignment error

Tooth width b (mm)	Reference diameter (mm)
	5≦d ≦20	20＜d ≦50	50＜d ≦125	125＜d ≦280
4≦b≦10	17	18	19	20
10＜b≦20	19	20	21	22
20＜b≦40	22	23	24	25

Accuracy of Spur Gears: former JIS B 1702:1976 Grade 2 (equivalent to new JIS B 1702-2:1998 Grade 6)

Gear allowable error

Module	Error	Reference diameter (mm)
		5≦d ≦20	20＜d ≦50	50＜d ≦125	125＜d ≦280
0.5	Single pitch error	6.5	7	7.5	8.5
	Cumulative pitch error	16	20	26	35
	Total profile error	6.5	7.5	8.5	10
	Allowable full engagement of both tooth flanks	15	19	23	30
	Allowable tooth space runout	13	16	21	28
0.8	Single pitch error	6.5	7	7.5	8.5
	Cumulative pitch error	16	20	26	35
	Total profile error	6.5	7.5	8.5	10
	Allowable full engagement of both tooth flanks	16	20	25	31
	Allowable tooth space runout	13	16	21	28
1.0	Single pitch error	6.5	7	7.5	8.5
	Cumulative pitch error	16	20	26	35
	Total profile error	6.5	7.5	8.5	10
	Allowable full engagement of both tooth flanks	18	21	26	33
	Allowable tooth space runout	13	16	21	28
1.5	Single pitch error	6.5	7	7.5	8.5
	Cumulative pitch error	16	20	26	35
	Total profile error	6.5	7.5	8.5	10
	Allowable full engagement of both tooth flanks	19	23	27	34
	Allowable tooth space runout	13	16	21	28
2.0	Single pitch error	6.5	7	7.5	8.5
	Cumulative pitch error	16	20	26	35
	Total profile error	6.5	7.5	8.5	10
	Allowable full engagement of both tooth flanks	22	26	31	37
	Allowable tooth space runout	13	16	21	28
2.5	Single pitch error	7.5	7.5	8.5	9
	Cumulative pitch error	17	21	27	35
	Total profile error	9.5	10	11	13
	Allowable full engagement of both tooth flanks	22	26	31	37
	Allowable tooth space runout	13	17	21	28
3.0	Single pitch error	7.5	7.5	8.5	9
	Cumulative pitch error	17	21	27	35
	Total profile error	9.5	10	11	13
	Allowable full engagement of both tooth flanks	28	31	36	43
	Allowable tooth space runout	13	17	21	28

Allowable total alignment error

Tooth width b (mm)	Reference diameter (mm)
	5≦d ≦20	20＜d ≦50	50＜d ≦125	125＜d ≦280
4≦b≦10	8.5	9	9.5	10
10＜b≦20	9.5	10	11	11
20＜b≦40	11	11	12	13

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