TABLE OF CONTENTS ANSI Standard Keys and Keyseats. American National Standard, B17.1 Keys and Keyseats, based on current industry practice, was approved in 1967, and reaffirmed in 1989. This standard establishes a uniform relationship between shaft sizes and key sizes for parallel and taper keys as shown in Table 1. Other data in this standard are given in Tables 2 and 3 through 7. The sizes and tolerances shown are for single key applications only.
| Nominal Shaft Diameter | Nominal Key Size | Normal Keyseat Depth | ||||
|---|---|---|---|---|---|---|
| Height, H | H/2 | |||||
| Over | To (Incl.) | Width, W | Square | Rectangular | Square | Rectangular |
| 5/16 | 7/16 | 3/32 | 3/32 |
| 3/64 |
|
| 7/16 | 9/16 | 1/8 | 1/8 | 3/32 | 1/16 | 3/64 |
| 9/16 | 7/8 | 3/16 | 3/16 | 1/8 | 3/32 | 1/16 |
| 7/8 | 1 1/4 | 1/4 | 1/4 | 3/16 | 1/8 | 3/32 |
| 1 1/4 | 1 3/8 | 5/16 | 5/16 | 1/4 | 5/32 | 1/8 |
| 1 3/8 | 1 3/4 | 3/8 | 3/8 | 1/4 | 3/16 | 1/8 |
| 1 3/4 | 2 1/4 | 1/2 | 1/2 | 3/8 | 1/4 | 3/16 |
| 2 1/4 | 2 3/4 | 5/8 | 5/8 | 7/16 | 5/16 | 7/32 |
| 2 3/4 | 3 1/4 | 3/4 | 3/4 | 1/2 | 3/8 | 1/4 |
| 3 1/4 | 3 3/4 | 7/8 | 7/8 | 5/8 | 7/16 | 5/16 |
| 3 3/4 | 4 1/2 | 1 | 1 | 3/4 | 1/2 | 3/8 |
| 4 1/2 | 5 1/2 | 1 1/4 | 1 1/4 | 7/8 | 5/8 | 7/16 |
| 5 1/2 | 6 1/2 | 1 1/2 | 1 1/2 | 1 | 3/4 | 1/2 |
| Square Keys preferred for shaft diameters above this line; rectangular keys, below | ||||||
| 6 1/2 | 7 1/2 | 1 3/4 | 1 3/4 | 1 1/2 [a] | 7/8 | 3/4 |
| 7... |
