How to Drill a 1-Inch Hole in an Angle Iron

Drilling a large hole in angle iron can be difficult unless you have the proper tools. You do not need to have access to a metal fabrication shop to obtain the proper tools to drill the large hole. With a vise, a 3/8th drill and two step-down bits you can quickly and easily drill holes in angle iron up to 3/8th of an inch thick. To ease the operation, cutting fluid is required to reduce friction between the drill bits and the angle iron.

Things You'll Need

• 2 inch by 2 inch by 1/4 inch angle iron
• Vise
• Tape measure
• Combination square
• Awl
• Hammer
• Center punch
• 3/8th inch drive drill
• Cutting and tapping fluid
• Self-starting 1/8th to 1/2 inch step-down bit
• 1/2 inch to 1 inch step-down drill bit
• Grinder
• Flapper wheel

Instructions

1. Clamp the angle iron in the vise. Make sure that the flange to be drilled is lying parallel to the floor.

2. Measure and mark the spot where you want the 1-inch hole in the angle iron. With the combination square and awl, scribe a line at the mark. Measure in 1 inch from the bend of the angle and place a mark with the awl. Set the combination to the 1 inch mark. This will mark the center line of the angle. Scribe a line, holding the combination square against the bend in the angle, perpendicular to your distance mark.

3. Center mark the point where the two lines cross. Hold the center punch on the cross-hair formed by the two lines. Strike the center punch with the hammer.

4. Insert the small step-down bit into the 3/8th drive. With a moderate amount of pressure, start drilling on the center punch mark. When you get 1/8th of an inch into the angle, stop the drilling and add cutting fluid to the partial hole. Continue drilling the hole. Add cutting fluid as needed to keep the step-down bit cool. Run the small step-down bit completely through the angle.

5. Exchange the small step-down bit for the 1/2 to 1 inch step-down bit. Apply a liberal amount of cutting fluid to the step-down bit and the hole in the angle. Continue drilling the hole while applying moderate pressure to the drill bit. Apply cutting fluid liberally to the step-down bit, as the larger diameter bit will generate heat quickly. Run the large step-down bit entirely through the angle iron.

6. Remove the bur from the angle iron hole. Release the angle iron from the vise. Flip the angle iron over and remove the bur from the exit side of the 1-inch hole.

References

• Self Starting 1/8th to 1/2 inch Step Down Bit
• 1/2 inch to 1 inch Step Down Drill Bit