Taps & Takeoffs · Taps & Takeoffs

Square-to-round tap

Rectangular main to round branch

ConnectionSquare base with round collar
SupportBranch hanger near collar

Before you start

  • Confirm square-base size, round collar size, branch route, and opening location.
  • Check that the base will not bridge a crossbreak, seam, or reinforcement.
  • Inspect the round collar for roundness and the square base for flatness.
  • Control the cookie before the final cut.

Tools and materials

Square-to-round tap, layout tools, approved cutting tools, clamps, approved fasteners, sealant, branch hanger, and deburring tools.

Lay it out

  1. Mark the rectangular opening from the branch centerline.
  2. Keep the square base on a flat area of the main.
  3. Align the round collar with the branch route.

Set and support it

  1. Support the main if the face is weak or bellied.
  2. Clamp the square base flat.
  3. Install the first round-branch support.

Make the connection

  1. 1

    Cut the opening and remove the cookie.

  2. 2

    Deburr and clean the edge.

  3. 3

    Set the square base flush.

  4. 4

    Square and center the round collar.

  5. 5

    Clamp the base.

  6. 6

    Fasten evenly.

  7. 7

    Seal the base perimeter.

  8. 8

    Connect and support the round branch.

Check the install

  • The base sits flat.
  • The collar remains round.
  • The branch is independently supported.
  • The perimeter seal is continuous.

Common mistakes

  • Bridging a crossbreak with the base.
  • Pulling the collar sideways with the branch.
  • Fastening a warped base.
  • Using sealant to fill a large gap.

Stop and ask

Stop if the base bridges a crossbreak, seam, or reinforcement, or if the round collar cannot align without side load.