# Tenon Tips & Coped Rails *Mitred tenon tips, round-tenon wedges, and coped stile-and-rail joints* **Names:** `tip` `wedge` `stile_and_rail` Three gaps in the tenon family, closed by ADR-0026. Source of truth for the language is `docs/KDL_AUTHORING.md` §8 (the joinery section); this page is the agent's quick card. ## When to use - **`tip mitre=#true`** — two rails tenon into the *same* post from different faces (a desk's apron and side apron into one leg; a chair's seat rail and side rail). Their tenons would cross inside the leg; mitring the tips lets each be long. Without it the `tenons-meet` rule refuses the pair. - **`wedge` on a `round_tenon`** — a round tenon driven through its mortised part and wedged in a kerf (a stool leg through its seat, a chair stretcher through a leg). The rectangular `mortise_and_tenon` has had `wedge` since M15; this is the round one. - **`profile "ogee"` (or any moulding) on `stile_and_rail`** — a cope-and-stick door or frame: the inside edges are stuck with a moulding, and each rail end is coped to it. `profile "square"` (the default) is still the flat frame. ## Syntax Mitred tips — one line in the body of **both** joints that meet: ```text joinery mortise_and_tenon name=Apron_to_Leg { tenon_thickness 10.0 tenon_length 48.0 clearance 0.2 tip mitre=#true } ``` Round-tenon wedge — the tenon must be through (`through #true`, or `length` reaching the far face); the kerf is sawn across the grain of the mortised part: ```text joinery round_tenon name=Leg_to_Seat { diameter 22.0 length 40.0 through #true wedge kerf=3.0 depth=18.0 flare=2.0 flare_depth=10.0 } ``` Stuck profile — `profile` is a moulding name, `profile_size` its projection in mm, and `profile_face` the way the frame's show face looks **in the assembly's axes**, written as a CEL string (`"'neg_y'"`): ```text profile "ogee" // ovolo cove ogee thumbnail half_round cockbead; "square" is flat profile_size 5.0 profile_face "'neg_y'" // pos_x neg_x pos_y neg_y pos_z neg_z ``` ## Example A single door, stiles and rails 20 mm thick, the front (`neg_y`) stuck with a 5 mm ogee. The right stile is the left turned half round and the bottom rail is turned over; the sticking still lands on the front of all four members, because `profile_face` is a world direction. ```kdl project name="stuck_door" units=mm schema_version=1 { materials { material Softwood type=softwood } component DoorStile { stock Softwood 60.0 20.0 500.0 groove target=panel face=pos_x width=8.0 depth=10.0 offset=6.0 mark RailSeat_Top x=60.0 y=10.0 z=-30.0 normal=pos_x mark RailSeat_Bot x=60.0 y=10.0 z=-470.0 normal=pos_x } component DoorRail { stock Softwood 280.0 20.0 60.0 groove target=panel face=neg_z width=8.0 depth=10.0 offset=6.0 mark Stile_Left x=0.0 y=10.0 z=-30.0 normal=neg_x mark Stile_Right x=280.0 y=10.0 z=-30.0 normal=pos_x } joinery stile_and_rail name=DoorFrameJoint { groove_width 8.0 groove_depth 10.0 stub_tenon_length 12.0 profile "ogee" profile_size 5.0 profile_face "'neg_y'" } assembly Root { part DoorStile_L instance=DoorStile { pos x=0.0 y=0.0 z=0.0 } part DoorStile_R instance=DoorStile { pos x=400.0 y=20.0 z=0.0 rot z=180.0 } part DoorRail_Top instance=DoorRail { pos x=60.0 y=0.0 z=0.0 } part DoorRail_Bot instance=DoorRail { pos x=60.0 y=20.0 z=-500.0 rot x=180.0 } join joint=DoorFrameJoint male=DoorRail_Top@Stile_Left female=DoorStile_L@RailSeat_Top join joint=DoorFrameJoint male=DoorRail_Top@Stile_Right female=DoorStile_R@RailSeat_Top join joint=DoorFrameJoint male=DoorRail_Bot@Stile_Left female=DoorStile_L@RailSeat_Bot join joint=DoorFrameJoint male=DoorRail_Bot@Stile_Right female=DoorStile_R@RailSeat_Bot part DoorPanel role=panel { stock Softwood 296.0 8.0 396.0 pos x=52.0 y=6.0 z=-52.0 } } } ``` ## Pitfalls and diagnostics - `tenons-meet` — two tenons run into each other inside one part. Shorten them, or write `tip mitre=#true` on **both** joints. `tip-mitre` — the mitre needs tenons that meet at an angle (parallel axes have no bisector), and the bisector plane may not cut a tenon's own rail: use shorter tenons. The mortises are **not** clipped to the mitre (they stay the full rectangular pockets); only the male tips are. - `wedge-kerf` — the wedge needs a *through* round tenon (`through #true`); `depth` must be at least `flare_depth` and at most three quarters of the tenon's run through the mortised part; a kerf may be no closer than 1.5× its width to the tenon's surface or another kerf. `wedge-grain` — the wedges spread the tenon along the mortised part's **grain** (spreading across it splits the part): declare `grain` on it, otherwise the longer of its two faces square to the tenon is taken; a tenon in end grain is refused. `wedge-flare`, `wedge-frame` — see `docs/KDL_AUTHORING.md`. - `params` — a stuck `profile` needs both `profile_size` and `profile_face`; an unknown profile or face word is named. `profile_size`/`profile_face` with `profile "square"` is only a warning (they do nothing). - `cope-profile` — the sticking would cut into the panel groove (`profile_size` larger than the wood between the show face and the groove: for a 20 mm member with an 8 mm groove, 6 mm), is deeper than half the rail's width, `profile_face` names a narrow edge of the rail or a way no member's side face looks, or the shoulder is off square. - `profile_face` is a **world** direction, never part-local: a door's right stile and bottom rail are usually the same component turned. Check the face against the *assembly*. - The cope has no clearance: `clearance` belongs to the groove (D8, ADR-0012). The cope is the stile's sticking void exactly, to the chord of the 16-segment section. ## See also - `docs/KDL_AUTHORING.md` §8 — "Mitred tips", the round `wedge`, and the `stile_and_rail` stuck-profile paragraph. - `docs/adr/0026-tenon-tips-wedges-and-coped-rails.md` — the three decisions and their evidence; RFC-0041, RFC-0126, RFC-0127. - `docs/agent-reference/nodes.md` — the node index. - Examples: `examples/desk.kdl` and `examples/dining_chair.kdl` (`tip mitre=#true`); `docs/styles/models/stile-and-rail.kdl` (the glossary's frame joint). ## Names Every name this page declares, how the example library uses it, and the shortest real use. ### `tip` node in 15 of 116 examples (22 uses). Shortest real use, from `deco_console_table.kdl`: ```kdl tip mitre=#true ``` ### `wedge` node in 6 of 116 examples (8 uses). Shortest real use, from `wedged_post_and_rung_stool.kdl`: ```kdl wedge kerf=3.0 depth=18.0 flare=2.0 flare_depth=10.0 ``` ### `stile_and_rail` joinery kind; value in 9 of 116 examples (9 uses). Shortest real use, from `ebonised_incised_cabinet.kdl`: ```kdl joinery stile_and_rail name=PanelFrame { groove_width panel_th groove_depth groove_d stub_tenon_length stub_l profile "square" } ``` ## Related terms - [Kusabi](/almanac/techniques#kusabi) - [Rail](/almanac/techniques#rail) - [Stile](/almanac/techniques#stile) - [Stile-and-rail joint](/almanac/techniques#stile-and-rail) - [Wedged tenon](/almanac/techniques#wedged-tenon)