S-and-Drive Square Duct · Field-made drive
Make a replacement drive
Missing drive cleat
Task typeField-made drive
Tools / equipmentBrake, snips, hammer
Before you start
- Confirm field fabrication of the drive cleat is allowed.
- Match the material, gauge, profile, and side-seam length to the approved construction.
- Inspect the duct side locks before making the replacement.
Lay it out
- Measure the full side seam and include the required end allowance.
- Mark the drive folds consistently so the cleat grips without spreading the duct hem.
Set and support it
- Form the drive on a stable brake or approved forming tool.
- Keep the strip straight; a twisted drive will jam and damage the lock.
Make the connection
- 1
Cut the drive strip to size and deburr it.
- 2
Form the drive profile to match an approved sample or detail.
- 3
Test the profile on scrap or the lock edge.
- 4
Start the drive square by hand.
- 5
Seat it fully without tearing the side hems.
- 6
Secure the ends and finish the joint.
Check the install
- The drive fits the side lock snugly without forcing it open.
- The profile and gauge match the project construction.
- The drive is straight and fully seated.
- Ends are secured and free of burrs.
Common mistakes
- Using a flat strip or improvised fold that does not lock the seam.
- Cutting the drive too short.
- Making the profile too tight and hammering it over the edge.
- Using mixed or corroded scrap.
Stop and ask
Stop if the correct profile cannot be verified, the side lock is damaged, or field-made drive cleats are not approved.