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Asphalt AnchorsAsphalt Anchors

Aligning Anchor Holes with a Template and Punch

When you install more than one anchor for the same object, the holes must match the mounting holes in that object. Small errors add up quickly: a hole that is off by 1/4” may still work for two anchors, but with four anchors it can be nearly impossible to get every bolt to line up.

Most alignment errors happen in the first 1/2” of drilling. A masonry bit tends to skip and wander on the asphalt surface before it bites, so a hole that starts on your mark can still end up off target. The fix is to make a starting dimple for the bit before you drill.

This method works even for tight patterns. We have installed SP58 anchors 5” apart, the minimum spacing, and had every bolt line up. See the spacing requirements for how close anchors can go.

What you need

Section titled “What you need”
  • A hole-spacing template made from paper, cardboard, plywood, or anything else you can mark accurately
  • A pointed tool you can hammer into asphalt, such as a 3/8” center punch or a concrete chisel
  • A hammer

See Center punches and chisels for examples you can buy locally.

Steps

Section titled “Steps”
  1. Make a template. Trace the mounting holes from the object you are anchoring, or measure and mark the hole pattern carefully. Mark the center of each hole.
  2. Position the template. Lay the template on the asphalt exactly where the object will go.
  3. Punch each hole location. Place the punch or chisel tip on the center of a hole mark and hammer it 6–10 times, until it is at least 1/2” into the asphalt.
  4. Knock the punch loose. Tap it side to side to free it, then move to the next mark. Repeat for every hole before you start drilling.
  5. Drill. Remove the template and start the drill bit in each punched dimple. The dimple keeps the bit from skipping, so the hole starts exactly where you marked it.

Then continue with the normal installation steps.