Install guide
Taps and spin-ins
The hole is only one part of the job. The branch still has to be squared, held flush, fastened, and sealed.
Field-reviewedField fabricationInstall sequenceUpdated July 2026
Field sequence
- Confirm the tap size, location, airflow direction, clearance, and branch route.
- Lay out the opening from a reliable reference. Check the other side before cutting.
- Support the cookie and leave a small tab until you are ready for the final cut so the scrap cannot fall into the duct, ceiling, or onto someone below.
- Remove the cookie, retrieve it, and deburr the opening.
- Set the tap or spin-in into the opening and square the throat or branch from the main duct reference.
- Hold or clamp the tap flush. A bellied duct face can make the tap pitch or cock even when the cut is correct.
- Fasten in a balanced sequence so the tap stays square.
- Seal the perimeter and verify the damper or scoop, when present, can operate and remain accessible.
Stop and get direction when
The opening lands on reinforcing, a seam, liner, a rated assembly, another trade, or the branch cannot be squared without distorting the main duct.
Say this
“I laid out the tap at [location], but the duct face is bellied and the branch will not sit square. I have not fastened it. Can you check the reference you want me to use?”
Before you leave it
- Cookie retrieved.
- Cut edge deburred.
- Tap is square to the main.
- Flange sits flush.
- Fasteners and seal are complete.
- Damper remains accessible and operable.