1:6 and a 1:8

Justin,

You are correct about the 1:8 being for hardwood. The 1 and 8 are the base and altitude of a right triangle. Layout a right triangle with the base at 1 inch and the altitude (height) at 8 inches and then connect the points to complete the hypotenuse. Use your sliding bevel square to match the base/hypotenuse angle. Now you can transfer the angle to your work piece to layout the dovetails. You can make a reference board with both the 1:6 and 1:8 layouts for quick, future reference. I have even seen these permenantly scribed on workbenches and even the outfeed table of a table saw.

Lew

You can take Lew’s explanation to the bank.

Lee

-- No piece is cut too short. It was meant for a smaller project.

I posted about making a dovetail template (and posted it as a project), which has the layout angles as well as a square. I also had to issue a retraction when I realized that I needed to have both directions of an angle represented on the template – whoops! So look at the template and see where I went wrong. If you did one, you could do 1:6 on one side and 1:8 on the other (with no square), or just split the difference and do both ways of a 1:7 and a square.

-- Eric at http://adventuresinwoodworking.com

Thanks for the Reply Lew,

How did they come up with them numbers. They just looked the best, What made them the standers to go by? Why not a 1:7 and a 1:5?

Sorry to be a pain,

Justin

I am not sure about the origin and in fact have seen the numbers 1:7 listed some place. Maybe, like you said, these are pleasing to the eye. Maybe they provide the best ratio of strength to size factors. I am sure that one of the Lumberjocks members has more knowledge than me and hopefully they can give us both the answer.

I really like Eric’s setup jig. It makes it alot easier to quickly set the bevel guage instead of trying to align the blade with a scribed line, on a piece of wood.

Lew

Actually, the jig is intended to replace the bevel gauge, not set it up. You put the appropriate ratio (like 1:6) on the edge of the board, and the part of the template hanging down is your line to mark. Plus, having a square on it as well really helps with quicker and easier layout of the squared lines on your dovetail.

-- Eric at http://adventuresinwoodworking.com

Even better!

Lew

Justin,

It turns out that it does not really matter. Fine Woodworking(FW) tested dovetails with both angles and the results came up the same. What you want, really, it to pick a visually interesting angle. I cut my dovetails without any guide and none of my angles are the same. I am guessing I make the angle random between 1:5 to 1:8.

The FW people debunked a lot of myths about dovetails in that article, not only the 1:6 vs 1:8 angles. They also showed that skinny pins are not weaker that wide pins (they are actually slightly stronger).

Alin

-- -- Alin Dobra, Gainesville, Florida

Thanks for the reply guys.

Justin

Here’s the article Alin is referencing: http://www.taunton.com/finewoodworking/SkillsAndTechniques/SkillsAndTechniquesPDF.aspx?id=2712

-- 10 fingers, 2 eyes, and healthy lungs. for now. :P