How it connects
The head enters the flange slot and bears beneath its edges, resisting upward pull. A nut on the separate threaded shank clamps the toilet down. This head-to-slot interface provides retention, not a fluid seal.
Male and female halves
The projecting captive head is the male member in this connection; the receiving flange slot is its mate. Male here describes the head/slot geometry, not the external thread on the opposite portion of the bolt.
Usually connects to
- Compatible closet-flange bolt slot
Common sizes
- One plastic bolt example: head 17.78 × 12.7 mm, 4 mm thick. Check the actual flange slot; these are not universal dimensions.
Where it is used
Floor-mounted toilet anchoring
How to recognise it
Look for a broad, flattened head beneath an upright bolt shank, sized to bridge the flange slot. In the installed assembly the head is retained below the slot edges and the threaded shaft points upward through the toilet mounting hole.
Often confused with
| Confused with | How to tell them apart |
|---|---|
| Closet bolt external thread | The thread mates with a nut above the toilet base; the broad captive head bears beneath the flange slot without threading into it. |
Also called
Closet bolt T-head captureToilet flange bolt head
Good to know
A white plastic bolt example has a 17.78 × 12.7 mm head, 4 mm thick. These are product-specific observations; check the flange slot for compatibility.
Design with real parts
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