Step 3: Time to cut and drill
Mount the bar stock in a vice or get a really good grip and get after it with a hacksaw. Cut the bar stock to your estimated length. After you cut it, take it back to the bike and check the location for the first bolt hole you must drill.
Once you know exactly where you want the first hole, use a punch to create a starting point and then mount the stock back into the vice. The punch isn't necessary, but it helps to keep the drill bit from wandering when starting the hole.
Double-check the second hole location before drilling it. Once two holes are drilled, triple check the hole locations by mounting the drop bolt on the bike and sliding the brake into place. The brake pads should align with the rim. If the holes are spaced incorrectly, there will not be enough pad adjustment on the brakes to make them align with the rim. If that happens, start over.