Thursday, July 30, 2009

What comes first? The pins or the tails?

The first 'religious' discussion for this batch of postings is whether to cut the pins first or the tails first.

There is a reason to cut tails first in a production environment - you can stack half a dozen boards in the vise and cut the tails on all of the boards at once. This, arguably, saves you a bit of time. Not a lot of time, as the time spent cutting is not great compared to the time spent chopping, but in a production environment a bit of time saved can be important.
Rob Cosman - arguably the most influential of the current crop of dovetail gurus - tells us to cut the tails first.

Looks like there is plenty of reason to cut the tails first, eh?

Well... maybe not.

There is a drawback to cutting the tails first. A big one. That drawback is that you need to scribe the tails onto the end-grain of the pin board. There are three problems involved in scribing from tails to the pinboard. The first is that you are scribing onto end-grain, so it's much harder to see the resulting line even if the end-grain of the pin-board has been planed to perfection. The second is that you are trying to scribe inside a small cavity where there is not enough room for a pencil or even an awl, so you have to use a blade, and that leads us to the third problem. The third problem is that you have to use a thin blade to scribe, and that can be hard to do without taking a slice from your tail or taking the wrong angle, as the blade wants to follow the path its on whether that path is the right one or not.

If, however, you cut the pins first and use them to scribe the tails then you are marking onto face grain, and you have plenty of room to use a pencil or an awl.

I always get better results when I cut the pins first, and Frank Klaus, the Godfather of Dovetailing, says to do the pins first. So did Tage Frid, before his unfortunate passing.

For me my preference is, and will always be, to cut the pins first.


Bob Rozaieski said...

Another situation where you really have to cut the pins first is half blind dovetails. There's really no way to accurately mark half blind pins from the tails.

Metalworker Mike said...

I was a bit confused by that for a moment until I figured out that you must be talking about a half-blind dovetail where the tails are blind, rather than the pins. The type of half-blind dovetails used on drawer fronts can be marked out from tails to pins, but I can see how if you were doing them blind 'the other way' perhaps for casework, it would be miserable to mark from tails to pins.