# Pin the Tail on the joint



## JeffP (Aug 4, 2014)

Newbie here…

For dovetail joints, what's the reasoning behind the names given to the two sides of the joint?

Why is a "tail" called a tail?

Why is a "pin" called a pin?

How can I remember which one is which?

I had hoped if I stared at them long enough one of them would jump out as really making sense, at which point I could just remember that one and the other would follow along. So far, it hasn't happened.


----------



## rad457 (Jun 15, 2013)

Looks like a Doves Tail? tail is male, pin is female. or is it the other way around?


----------



## crank49 (Apr 7, 2010)

Sides of the pin are perpendicular to the end of the board. The sides are parallel to each other, same width at base and top of the pin.
The sides of the tail are reverse tapered at an angle to the end of the board. The tail is smaller at its base than at its top.


----------



## rad457 (Jun 15, 2013)

> Sides of the pin are perpendicular to the end of the board. The sides are parallel to each other, same width at base and top of the pin.
> The sides of the tail are reverse tapered at an angle to the end of the board. The tail is smaller at its base than at its top.
> 
> - crank49


Say what, on my first scotch and it must be good cause I'm really confused now? Only thing I understood was tail smaller at the base?


----------



## AlaskaGuy (Jan 29, 2012)

Print out this picture. Take to one of those copy and have them enlarge it and hand it on you shop wall.


----------



## JeffP (Aug 4, 2014)

Thanks Alaska Guy…this works…for the entire time that I'm staring at your picture.
Once I avert my gaze, I immediately can't remember anymore because it makes no sense to me.

Could it be that it has more to do with how the pieces are used in a piece of furniture rather than the shape of the joint fingers?

Is a "tail piece" a particular part of a drawer for instance?

Or similarly, in old-timey furniture was there something called a "pin board" completely separate from what joinery was used?


----------



## WillliamMSP (Jan 3, 2014)

Hmmmm… how about, "don't pull a tiger, or drawer, by its tail"?

Dovetails deal with force/movement really well in one direction, but not the other. Imagine a dovetailed drawer assembled without glue - you wouldn't make the front of a drawer out of a tail board, because pulling on it would simply pull the joint apart. Pins, on the other hand, are wedged such that pulling on that side wouldn't pull the joint apart, even without glue.


----------



## JeffP (Aug 4, 2014)

So the tail pieces always go on the sides (rather than front and back) of a drawer.

That's useful information and makes sense.

It is, to my mind, also just another logical inconsistency with the naming. If you handed most people a drawer and asked them to point to the "tail piece", most of them would point to the back.


----------



## hotbyte (Apr 3, 2010)

Here is image from Google a Dove's (the bird) tail. As rad457 said, it has the same fan shape as the tails on the tail board.


----------



## JeffP (Aug 4, 2014)

Yeah, but the pins have that same shape…just in cross section.


----------



## hotbyte (Apr 3, 2010)

Just don't look at the boards from that angle


----------



## ElChe (Sep 28, 2014)

Think of the function. The pins slide into the spaces between the tails. So in a drawer, the pin boards would be front and back and the tail boards would be the sides. When you open the drawer over and over this orientation creates strength in the joint because the pins jam into the tails and won't come out. The tails take the stress.


















In this diagram you can tell that the joint can only be assembled by sliding the pins into the sockets between the tails.

Pins are cut with the handsaw blade plumb to the end of the board being cut and the plumb blade is cutting at an an angle that looks like a vee when looking at board end from the top.

Tails are cut with the handsaw blade tilted and not plumb but the tilted cut starts at 90 degrees to the end of the board. When looking from the top of the board, the tails are the same thickness front and back and don't look like a vee.

Always think of function. The pins slide into the socket between the tails. The tails cannot slide into the socket between the pins.


----------



## HornedWoodwork (Jan 28, 2015)

I see your point that at some level pins and tails have similar shapes, but for me the "tail" shape is distint in the joint when the tail is wider than the pin. In Elche's drawing the pins and tails are roughly equal but in Alaska guy's the tails are much larger. Thus the pins are much thinner. For many handcutters the tails are usually much thicker and look more like actual doves tail's than the mating pins will.

As for how to remember which is which, cut a few hundred of them and you can call the parts whatever you want.


----------



## AlaskaGuy (Jan 29, 2012)

Hand cut.


----------



## JeffP (Aug 4, 2014)

Alaska… that looks more like a beaver tail.


----------



## JeffP (Aug 4, 2014)

While it was probably intended somewhat tongue in cheek, I think maybe we will have to resign ourselves to accepting the suggestion above by Hotbyte…just don't look at it from that angle.

I will just have to remember that the "dove-tail" shape refers to that which is in the plane of the board, and not on the end-grain.

I had hoped that some old-timer here would be able to tell us the history and that it would all become clear at that point…sadly, not every bit of nomenclature actually HAS a logical reason behind it. "Tails" and "Pins" would seem to number among those.


----------



## Bobbal (Feb 24, 2015)

Maybe we should move to change the name from dovetail joint to wedgie!


----------

