How it connects
The male square tubular stub slips snugly inside the bottom opening of a hollow square fence post, typically retained and secured with through-bolts, self-tapping set screws, or pinch bolts.
Male and female halves
Male spigot/stub designed to insert into a matching hollow female square metal post.
Usually connects to
- hollow square metal fence post (female)
- square vinyl post sleeve
Common sizes
- Fits square-post interiors, generally nominal 1–4 in posts, including 1-1/2, 2, 2-1/2 and 3 in.
- A nominal 2 in post insert may be about 45–48 mm across, including a 45 mm (1.77 in) example; account for tube wall thickness.
Where it is used
ornamental iron fencingaluminum deck railingmetal signpost mountinggate post anchoringarchitectural metalwork
Variations
- surface mount floor flange with square stub
- in-ground male square anchor stub
- expanding internal post wedge anchor
- internal spigot with set-screw lock
- through-bolted internal post sleeve
- adapter spacer sleeve for post wraps
How to recognise it
Recognised as an upright hollow or solid square metal tube/stub protruding from a flat mounting flange or base plate, dimensioned slightly smaller than nominal square tube inside dimensions.
Often confused with
| Confused with | How to tell them apart |
|---|---|
| External square post base / collar / floor flange (female) | External female post bases fit over the outside of the post tube, whereas the male post sleeve is an internal stub that the post tube slides over. External sockets wrap around the outside of the post (female), whereas this male sleeve inserts inside the hollow post profile. |
| Decorative post base skirt / cover | Post base skirts are decorative non-structural trim pieces that hide the bolts, rather than load-bearing internal stubs. |
| round fence post sleeve | Round sleeves fit circular pipe or tubing rather than square profile tubing. |
Also called
square post base insertsquare fence post anchor stubmale post spigotinternal square post sleevesquare post spigotinternal post mount sleeveinternal post base flange
Good to know
Commonly used when anchoring ornamental steel or aluminum fences to concrete decks or patios without embedding the full post into poured concrete.
Related connections
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