| Allen Wrench Size Chart | |||||
| Allen Wrench Stock No. | Allen Wrench Hex Key Size | For Socket Head Cap | For Socket Head Set | For Button Head Cap | |
| English | #58-639 | 0.028" | N/A | #0 | N/A |
| #58-638 | 0.035" | N/A | #2 | #0 | |
| #56-271 | 0.050" | #0 | #4 | #2 | |
| #58-637 | 1/16" | #1 | #6 | #3 & #4 | |
| #56-270 | 1/64" | #2 & #3 | #8 | #5 & #6 | |
| #55-188 | 3/32" | #4 & #5 | #10 | #8 | |
| #55-189 | 7/64" | #6 | N/A | N/A | |
| #03-662 | 1/8" | N/A | ¼" | #10 | |
| #55-190 | 9/64" | #8 | N/A | N/A | |
| #55-191 | 5/32" | #10 & #12 | 5/16" | #12 & ¼" | |
| #55-192 | 3/16" | ¼" | 3/8" | 5/16" | |
| Metric | #58-636 | 0.9mm | N/A | M2 | N/A |
| #55-452 | 1.5mm | M1.6 & M2 | M3 | M2.5 | |
| #57-445 | 2mm | M2.5 & M2.6 | M4 | M3 | |
| #55-451 | 2.5mm | M3 | M5 | M4 | |
| #55-199 | 3mm | M4 | M6 | M5 | |
| #55-200 | 5mm | M6 | M10 | M8 | |