# When it comes to dovetails what is the significance of 1:6,1:7,1:8

I've been watching and reading about dovetails and you see workers put certain angle on their tails and pins. These angles can be decribed with number sets such as 1:6, 1:8 and other examples. Router bits would also be marketed with those numbers.

Most woodworkers will swear by certains numbers and insist that those are the only ones they would do. Even the commercial dovetail markers are branded with these values. There are some that would just free hand an angle but stay true to one of these angles.

What is the significance of the numbers and does it matter which ones I use?

What is the significance of the numbers?

They represent ratios that determine a dovetails angle. So in the case of 1:6 - for every unit you move up you also move 6 units over. These ratios are not usually mixed or changed on a single project. A simple trick to getting perfect angles, and to illustrate my point, uses a bevel guage and square. The always amazing Roy Underhill demonstrates this in this video "The Dovetail Variations"

Hard to tell from the picture but the bevels handle is resting so the guide itself is crossing 1 inch and 6 inches.

Using these tools the traditional woodworker could easily transfer any ratio to wood.

Of course there are many manufactured guides available as well that maintain these angles for you.

Below is a table that corresponds common ratios to angles. This way you can use whichever you are more comfortable with.

[D]oes it matter which ones I use?

There are a couple of schools of thought in this regard. In general many favour the 1:6 ratio but you will run into many who suggest using different ratios for hardwood and softwood. 1:8 for hardwood and 1:6 for softwood. However the exact ratio / angle is not important. What is important is the integrity of the overall joint. Glen D. Huey on a PopularWoodworking article words this sentiment well

What’s important is that you don’t get the slope so steep that your tails break off and your joint caves. Or that you don’t get the slope too straight that your tails slip from the pins, or that your joint has to rely only on glue for its strength. Between those two extremes anything goes.

If your tail breaks off while assembling the joint one of the considerations might be your angle is too steep...

• Beyond that, it's a matter of taste, deciding which angle looks right for this size dovetail in this project. Sep 19, 2015 at 4:02
• A bit beyond woodworking, I've seen "dovetail-like" joins in stone with a ratio 1:2. It was in an opera house and it helped join the handle along the stairs. I'll get a picture when it opens back. It blew my mind to see it Jun 9, 2020 at 12:49