Dovetail tail

A dovetail tail is the half of a dovetail joint on the end of the arriving part: a tongue that stands out of its shoulder and drops into a dovetail socket in the other part. Its closed end is round or square. Its flanks open toward the wide end by the cone and lean out by the flank angle, so the tail goes into its socket from the open side and cannot be pulled out square to it.

Dovetail tail. Drawn by the editor's own geometry code; right: the carved part in 3D.

When to use it

Use a tail where a joist hangs from a beam without steel: the tail on the joist’s end, its socket in the side of the beam. The tail runs down from the top face, so the joist drops in from above, and the cone pulls the joint tight as it goes in.

Fields

Field	Unit	Range or options	Default	What it changes
End		Start, End	End	The part end that gets the tail.
Shoulder (x)	mm	from 0	2972	Where the shoulder crosses the middle line of the tail, measured from the start of the part.
Middle (y)	mm		60	Where the middle line of the tail lies across the face.
Face		Top, Bottom, Front, Back	Top	The face the wide end lies on. The tail runs from there toward the opposite face.
Below the face	mm	from 0	0	How far below the face the wide end sits; 0 is at the face.
Wide end		Runs out through the face, Stops below the face	Runs out through the face	The wide end runs out through the face, as on a joist, or stops below it.
Length	mm	0.1 to 50000	82	From the wide end to the closed end, along the tail.
Width	mm	0.1 to 1000	44.04	The width on the line through the closed end, at the shoulder: the same measure as the socket's.
Stands out	mm	0.1 to 1000	28	How far the tail stands out of its shoulder: the depth of its socket, 28 mm with the usual cutter.
Cone angle	°	0 to 30	2.5	How much each flank opens toward the wide end. 0 is parallel.
Flank angle	°	5 to 35	15	The lean of the flanks, the cutter's: 15° with the usual 60/45 mm cutter.
Closed end		Square, End radius	End radius	Round, as a dovetail cutter leaves it, or square.
End radius	mm	0.1 to 1000	23	Radius of the round end, half the cutter diameter. Radius, width and cone are linked.
Inclination	°	0.1 to 179.9	Square (90°)	Leans the shoulder, for a sloping joist. 90° is square.
Angle	°	0.1 to 179.9	Square (90°)	Turns the shoulder in the face, for a joist that arrives skewed in plan. 90° is square.
Tongue turned	°	0.1 to 179.9	Square (90°)	Turns the tail about its own axis. 90° is square.
Width allowance	mm	-10 to 10	No allowance	Hundegger machining allowance on the width. BVX writes it; BTLx has no field for it and leaves it out with a warning. Empty is none.

Default: what Add fills in on a 3000 mm part of 120 x 120 mm.

Add a dovetail tail

Select the part in the Parts list.
Under Extra processings, click Add.
Type dovetail tail in the search field and pick Dovetail tail.
Set End and Face. The tail runs from that face toward the opposite one.
Under Place, set Shoulder (x) and Middle (y), or click Centre.
Check that the part shows a green check. If not, open the Issues tab.

A new tail is the usual Hundegger dovetail: a 15° flank, 28 mm standing out of its shoulder, a 46 mm round end and 2.5° of cone a flank, running from the face down to 38 mm short of the far face.

The card

The card draws the tail seen on the end of the part as you change it: its outline at the shoulder and, dashed, at its tip, with its length, round end and cone.

Under Size / shape, pick a Round or Square end and set its Length. A round end takes Round end Ø, and its width follows from the diameter and the cone; a square end takes Width. Cone per flank has picks for 0°, 2.5°, 3.75° and 5°, and Stands out for 20, 25 and 28 mm, where 28 is marked standard. Under Flank, a section across the tail shows its lean, with picks for 10°, 15° and 20°: 15° is the usual 60/45 mm cutter. Under Place, Below the face starts the wide end lower, and Wide end runs out through the face or stops below it. All values shows the values the way BTLx writes them, where 90° is square.

You can drag instead. In the drawing and in 3D, the handle where the shoulder meets the face moves the tail along the part and across it. In the other long view, where the run of the tail shows, the knob at the closed end of its tip sets the length, and the knob on the middle of its tip how far it stands out.

A shoulder at an angle

For a joist that slopes or arrives skewed, use Lean, as on a tenon at an angle: Shoulder lean leans the shoulder, with picks for 0°, 15°, 30° and 45°; Turn in the face turns its line on the face, and Tail turned turns the tail about its own axis. All three are measured from square, and Make square puts it back. The tail always stands square to its shoulder. In the drawing and in 3D, the knob at the far end of the dashed shoulder line leans it and the knob on the face turns it.

A shoulder that leans both ways, and a tail turned about its own axis, need a five-axis head: the card labels them Specialised machine.

In Fitting

The Dovetail joint for a member’s end in Fitting places a tail and its socket as a pair, with the same numbers, also on a joist that arrives at an angle: the tail then stands square to the host’s face. In the designer, Make the mate on the tail’s card adds its socket.

Housing

Enable Housing for a wider shoulder block and its matching recess. Set its length, width, depth and corner shape; 10 and 15 mm are quick depth picks. The tongue starts after the housing, and a mortise or socket runs on from its floor. Its depth is additional to the housing depth. Keep the tongue inside the housing and the complete cut inside the timber. Drag the housing depth handle in the drawing or in 3D.

BTLx carries the two cuts together as House or HouseMortise. BVX and BVN housing mappings are experimental: the export includes them with a warning and a preview, and Leave out removes the complete housed joint. BTL carries linked 052/053 housings with a specification caveat. BVN preserves imported 0506 and 17xx forms whose placement has not been confirmed. The existing Housed tenon joint keeps its full-width housing; Narrow housed tenon, Vertical housed dovetail and Horizontal housed dovetail bind the housing dimensions on both halves.

Machine export

BTLx writes every tail. BVX writes a tail in the form the shop’s own files use, square or turned in the face, with a note in the file to check the first part until a machine has cut one. A tail that leans, is turned about its own axis or stops below its face goes into the shop test pack only. BVN writes every tail in the shop test pack only, except one turned about its own axis, which it has no operation for. BTL carries the standard dovetail-tail record and warns where tool geometry needs receiver inspection. A square end goes to neither BVX nor BVN, because a dovetail cutter always leaves a round end: pick Round, or finish the end by hand.

A tail in a BTLx file, or in a BVX file from CAMBIUM, opens as a tail you can edit. A BVX tail gets a note that whether its width is measured at the shoulder or at the tip is still open; its socket carries the same reading, so the two still fit. A tail from another program’s BVX, and every tail in a BVN file, is kept as it came. See Import a machine file.

Format	Status	Details
BTLx	Supported	DovetailTenon, square or at any angle, round or square ended, running out through its face or stopped below it. A width allowance is left out, with a warning. Housing uses House with a nested DovetailTenon.
BVN (Hundegger)	Partly supported	Experimental, included with a warning unless you leave it out. Operation 1701 for a square end or one turned in plan, 1700 for one leaning, are experimental and included with a warning. A tail turned about its own axis has no operation. Housed tails use experimental 1720/1721; stopped tails and rounded housing are refused.
BVX2 (Hundegger)	Partly supported	DovetailTenon in the form of the shop's own files, on a square end or one turned in plan, with a warning in the file. Other angles, and a tail stopped below its face, experimental, included with a warning unless you leave them out. A square end is left out: a dovetail cutter always leaves a round one. Housing uses experimental House plus the raised DovetailTenon.
BTL 10.6	Partly supported	055 straight or angled tails; linked 052 housing. The receiver chooses the undercut cutter; allowances are omitted.
Machine	Specialised machine	A shoulder leaning both ways, or a tail turned about its own axis, needs a five-axis head, such as on a Hundegger ROBOT-Drive or K2. A square tail, or one on an end angled one way, any machine with a dovetail cutter makes. Which machine can cut it.

BTL status describes what the specification can represent. CAMBIUM imported our earlier BTL test files; confirmation applies to the tested forms and build. See BTL coverage for representation and receiver caveats.