Steel Solutions Center

2.4. Bolt Holes

2.4.1. What are the acceptable methods for making bolt holes?

Acceptable methods for making bolt holes include:

1. Punching

2. Sub-punching and reaming

3. Drilling

4. Hole sawing

5. Flame piercing and reaming

6. Thermal cutting, subject to surface quality requirements as discussed in 2.4.2

7. Water jet cutting

2.4.2. What variation in profile is generally acceptable for bolt holes?

The slightly conical hole that naturally results from punching operations is acceptable, as noted in Table 3.1 of the RCSC Specification. The width of slotted holes that are produced by flame-cutting, or a combination of punching or drilling and flame-cutting, should generally be not more than 1⁄32 in. greater than the nominal width except that gouges not more than 1⁄16 in. deep are permitted. Thermally cut holes subjected to fatigue are not addressed in Appendix 3 of the AISC Specification.

2.4.3. Must burrs be removed in bolted connections?

The RCSC Specification Section 3.4 states: "Burrs less than or equal to 1 ⁄16 in. in height are permitted to remain on faying surfaces of all joints. Burrs larger than 1 ⁄16 in. in height shall be removed or reduced to 1 ⁄16 in. or less from the faying surfaces of all joints."

2.4.4. Are there any special hole size requirements in members or bolts that are galvanized?

No. Holes for galvanized bolts or members are not permitted to be larger than those specified in Table 3.1 of the RCSC Specification.