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Stepper Motor dimensions inch size shafts table.

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Table of dimensions for shafts, keys and keyways for inch dimension Stepper motors

Note: This document annotates dimensional data specified by NEMA standard (see bottom of webpage). Many industry stepping motor manufacturers have chosen to deviate from this industry standard.

Legend
1) L minus LB (L-LB) is the preferred designation for the length of the shaft from the mounting surface of the flange. Dimension L-LB can be determined from dimension E+R included in the tables (L-LB = E+R).

Stepper Motor shafts, keys and keyways dimensions for inch size table.

Shaft number	D			E + R a
	Nominal in.	Tolerance		Nom. in.	Tolerance
		in.	in.		in.	in.
019	0.1875	0	-0.0005	0.812	+0.031	-0.031
020	0.1969	0	-0.0005	0.812	+0.031	-0.031
025	0.2500	0	-0.0005	0.812	+0.031	-0.031
031	0.3125	0	-0.0005	0.938	+0.031	-0.031
038	0.3750	0	-0.0005	1.250	+0.031	-0.031
044	0.4375	0	-0.0005	1.250	+0.031	-0.031
050	0.5000	0	-0.0005	1.500	+0.031	-0.031
063	0.6250	0	-0.0005	2.063	+0.031	-0.031
075	0.7500	0	-0.0005	2.250	+0.031	-0.031
088	0.8750	0	-0.0005	2.250	+0.031	-0.031
100	1.0000	0	-0.0005	2.500	+0.031	-0.031
113	1.1250	0	-0.0005	2.750	+0.031	-0.031

 

Shaft number	Key			Keyway						Maximum Continuous Shaft Torque lb-in.
	F, GD			F			GE
	Nom. in.	Tolerance		Nom. in.	Tolerance		Nom. in.	Tolerance
		in.	in.		in.	in.		in.	in.
019	b			b			b			0.74
020										1.0
025										1.35
031										3.5
038										5.6
044	0.0938	+0.0010	0	0.0938	+0.0020	0	0.052	+0.015	0	10.9
050	0.1250	+0.0010	0	0.1250	+0.0020	0	0.070	+0.015	0	15.2
063	0.1875	+0.0010	0	0.1875	+0.0020	0	0.108	+0.015	0	39.6
075	0.1875	+0.0010	0	0.1875	+0.0020	0	0.106	+0.015	0	73.0
088	0.1875	+0.0010	0	0.1875	+0.0020	0	0.104	+0.015	0	121.5
100	0.2500	+0.0010	0	0.2500	+0.0020	0	0.141	+0.015	0	190.6
113	0.2500	+0.0010	0	0.2500	+0.0020	0	0.139	+0.015	0	284

^a The shaft shoulder which is larger in diameter than the D dimension, and shown with length R, is an optional feature on inch dimension motors. For motors with this shaft shoulder; R maximum = T, R minimum = 0.
^b The key and keyway is not provided for shaft numbers 019 to 038. A flat on the shaft may be provided, optionally, for shaft numbers 019 to 038.

Reference: NEMA ICS 16 Standard