Are half pins required?

[Carl Beckett]

OK - after spending the last couple hours searching through all the fantastic discussions here on cutting dovetails, I still havent the original question I was searching for (as always, I learned a ton from you guys by reading, but I need to get moving for the day). But I KNOW this has been posted and addressed, so my apologies for the overpost (I just havent found it)

Are starting half pins a requirement for through dovetails? Or is it a matter of personal taste/style?

Some of the basic articles on dovetailing state that there are half pins at each end of the joint - without really explaining the why (I assume this is to keep the ends of the boards pulled tight - especially on something like a drawer front).

But then I see a number of projects posted here where someone has just started with a tail section.

In fact, on the project I am doing I did just this - started with a full tail and no half pin (will see about getting a pic up - the drawer front is about 8.5" high with ~1" tail widths). But I am only on drawer 1 of 18, so not the end of the world if I made a subtle tweak now. (although I like the way it looks from the front, with the evenly spaced tails).

Some great advice here. Teach me, oh great ones.......

[George Beck]

Hi Carl

I am certainly no expert in dovetailing, but I do make boxes so I make many dovetails. I do not think that starting and ending with half pins is required but it is traditional. There are some problems if the ending pins are less than half a pin as you can end up with a weak half pin prone to breaking (lets say perhaps 1/3 or less). On boxes where the lid fits in between the sides (cigar box style), My top half pin is thicker than the bottom half pin which is half a pin. This is to accommodate the thickness of the top so that when the box is opened, a small portion of tail is not showing. I just think that looks funny although would not hurt anything. I was taught to make what I call symmetrical dovetails (back when dragons roomed the earth), that is the tails were the same size and the width of the tail should be the same as the thickness of the material. The exposed front forms squares. The idea in those days was to make dovetails look uniform and almost machine made (the teacher would check several for uniformity). I was taught to layout the half pins, then evenly space the full pins using a calipers (like the Rob Cosman method). In the 70's the trend became to make hand dovetails not look like machine dovetails in order to differentiate hand work from machine-made. This led to tiny "London dovetails", varying size dovetails (krenovian) and such. Which is pretty neat. Although I spent much time learning "tensioned" (Krenov) dovetails, I have yet to find a customer who notices or cares much. I like the look of traditional evenly spaced "symmetrical" dovetails. That being said, Why cut them by hand? I use hand dovetails because it gives me options as to the size and spacing if required. For instance, on a drawer with a center slide, I make the center dovetail a bit wider to accommodate the groove or on a box where the sides are planed to 11mm where could I find an 11mm router bit? I will also sometimes space dovetails for no other reason than to accommodate a chisel size. Well, pardon the long rant. I know you don't have much time to read, so in summation: IMHO it is both a matter of taste and tradition. There were reasons for the tradition forming about half pins but it is not a law.

I have 6 boxes to make so I had better get busy.

George

[Casey Gooding]

Half pins are the way things are traditionally done. However, I did watch an episode of The Woodwright's Shop where Roy examined and copied a set of dovetails that ended in half tails. So, it has been done.

[Jim Koepke]

Half tails, half pins it is almost as long a running discussion as pins first or tails first.

I think the terms half pin or half tail actually has dual meaning. Since one side of the pin is the end of the board, it does not get cut, no matter how big it is, it is still only a "half pin." Look at the fancy thin "London style" pins that are very thin and you can see that the end pins have to be bigger than half size.

jtk

[Tony Shea]

Depending on the width of the half tail you end up with strength may become an issue. Dovetails typically have a fair amount of short grain due to the angle. When ganged together with a group of tails it usually is of no concern and really is a super strong joint. But if a half tail is subjected to much stress it seems as though there may be some strength issues. But this is probably not the case in drawers of relatively smallish size. It may not really be an issue at all, just a theory that really has no basis.

[Carl Beckett]

Thanks for all the comments - at this stage I am just starting on drawer #5 so I guess I will see how the first set goes and adjust for the second set if I dont like it.

I especially appreciated this comment:


"It may not really be an issue at all, just a theory that really has no basis. "

Strength of conviction........ sounds like something I would say.

[Carl Beckett]

Well, the better part of the day and this is what I ended up with. An exercise in learning, and improving my dovetail cutting skills. Not too bad at all.

Do note that these are just dry fit, so they arent as tight as they will be when I clamp and glue them. The two tricks that I found most helpful: Sawing to the line, and using a smaller chisel for paring. The last three drawers there was no paring of the sides, only removing waste, and then they went right together.

By the time I get the other 10 drawers done (a sister piece), I will have learned a great deal.

Also note - part of this wood is a bit punky - it was milled out of what would otherwise become firewood. Ill post something on the finished product (someday, assuming it actually gets done), but I get satisfaction out of making furniture out of wood that is less than perfect. I think this just means I like frustration, because its never square or uniform thickness or without defects, all of which require extra attention to get it all to go together.

191853 191854 191855 191856

[David Keller NC]

Carl - There is actually a reason to go with half-pins on the bottom of a drawer front beyond the problem of a half-tail coming loose because it's side-grain to end-grain gluing. In a traditional case, the drawers slide on runners. These runners are either tenoned into the front divider to make a full frame, or in antique pieces, simply nailed to the inside of the case sides. Over time, the runners wear, and because they're typically of a softer material than the primary wood (which the drawer dividers are made of), they wind up a bit lower in elevation than the drawer divider. On a drawer with a half-tail, the bottom corner is exposed end grain, which chips or splits easily. Over the course of many years, half-tails on through dovetails can lead to some significant chipping/splitting. I've seen it on at least a few antique pieces.

On the more usual half-blind drawer fronts, half-tails on the bottom do seem to separate from the drawer front because of glue failure. The shrinking/expanding of the wood due to humidity changes can often result in a warp at this half-tail point. I've seen this frequently on drawers constructed this way.

Having said all of that, many of us might not care too much about what happens to our furniture 100 years after we're dead, and there's no perfect construction method - they're all a "best" compromise.

[Roderick Gentry]

" It may not really be an issue at all, just a theory that really has no basis."

That actually makes some sense, particularly if the tails were on the side of the drawers as they should be, and once the glue starts to go.

If one uses half tails on a half lap drawer front that is the same height as the front, one will have an ugly notch in the continuity of the drawer front.

[Adam Cherubini]

Carl,

I think there are strategies involving half pins and tails. For thru dts, if you cut tails first and make all tails full, it may be difficult to align the tail board to the pin board (for marking) since you lost your common edge. Of course this works both ways. If you do pins first, and depending on how you normally align and mark boards, it may be difficult to align the boards.

So for thru joints, I think I usually start with tails and leave at least one half tail. The other thought is that having only one halfie helps me keep track of how the boards go together.

Drawer making is another long story I won't go into. But my quick answer is that the bottom joints are chosen to protect grooves or rabbets that house the drawer bottom. At the top of the sides of the drawer, Philly pieces are almost always molded so a half tail is problematic at the front (molding done before assembly). It works in the back if the back is held below the mold. I think I've seen a variety of situations there.

As far as small "london pattern" dts, again, I think there were functional (if incoorect) reasons for cutting them that way. My theory is that the tiny pins reduce the amount of exposed end grain of the drawer front. The drawer fronts were often of imported woods (like mahogany). We don't see that treatment elsewhere. While one may be able to find exceptions, I think these things were all thought out and craftsmen repeated what they were taught, sometimes not knowing themselves why it was done that way. I think it's a muistake to look at variation and assume the lack of uniformity indicates mere personal preference.

Adam