How it connects
The 4x4 lumber end or length drops into or slides through the open-top U-channel seat and is secured mechanically via structural wood screws, lag bolts, or through-bolts driven through pre-punched fastener holes in the side flanges.
Male and female halves
Female U-channel bracket socket mating with male solid wood beam/post end or continuous timber member.
Usually connects to
- Matching square/rectangular timber post or beam end: nominal 4 × 4, 6 × 6 or 8 × 8, or specified rough-cut lumber
- Nominal 4 × 4 is 3-1/2 in (89 mm) square; 6 × 6 is 5.5 in (140 mm) square
Common sizes
- Nominal 4 × 4 lumber is about 3.5 in (89 mm) square; receivers are listed around 3.55–3.65 in (90–93 mm), with flange heights/depths about 2–6 in (50–150 mm).
- Other sockets fit 6 × 6 (actual 5.5 in/140 mm), 8 × 8 (actual 7.5 in/191 mm) and true rough-cut 4/6/8 in posts.
Where it is used
Deck/post-and-beam timber framingPergolas, gazebos and patio coversOutdoor architectural structuresFences and porch rails
Variations
- Open-top 90° corner or T post-to-beam connector
- Continuous joist saddle
- Half/ground or elevated-standoff post base
- Two-/three-/four-way corner sleeve
- Open-corner or welded four-sided box sleeve
- Two-sided/U-shaped saddle
How to recognise it
Recognized as a formed or welded sheet/plate steel bracket having parallel vertical sidewalls spaced 3-1/2 inches apart over a base plate, open along the top face, with round fastener holes in the side flanges.
Often confused with
| Confused with | How to tell them apart |
|---|---|
| Closed 4x4 post sleeve socket | Closed sockets surround all 4 sides like a box or tube; open-top U-channel sockets have an open upper face allowing drop-in beam placement. |
| Strut channel (Unistrut) | Strut channel fittings are sized for 1-5/8 inch roll-formed steel channel with inward lips, not 3-1/2 inch solid timber lumber. |
| Rough-sawn 4x4 lumber bracket | Rough-sawn lumber is a full 4.0 x 4.0 inches (102 x 102 mm) and will not fit inside a standard 3-1/2 x 3-1/2 in sleeve. |
| Nominal 6x6 lumber socket | Nominal 6x6 sleeves measure 5-1/2 x 5-1/2 inches (140 x 140 mm) inside dimension. |
| Rough-sawn 4x4 timber socket | Rough-sawn timber post sockets have a full 4.0 in (101.6 mm) square internal dimension, whereas nominal/dressed 4x4 sleeves measure roughly 3.5 in to 3.6 in (89-92 mm). |
Also called
4x4 U-bracket socket; 4x4 post bracket socket; 4x4 post cap sleeve; 4x4 post bracket sleeve4x4 post-to-beam saddle; 4x4 post base socket; 4x4 post saddle socket4x4 timber connector channel4x4 joist/beam saddle bracket4x4 lumber sleeve connector4x4 pergola corner sleeve socket4x4 post anchor collarpost bracket seat
Good to know
Commonly found on modular pergola fittings and corner connectors (such as Simpson Strong-Tie Sage / Outdoor Accents and pergola kit brackets) where horizontal 4x4 beams seat into perpendicular or corner channels. Additional standard references: IBC (International Building Code).
Design with real parts
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