dumb question about dovetail router bits

[Jim Colombo]

I know this will sound dumb but I was wondering what the difference is between a 7 & 14 degree dovetail (obviously the angle) but what's the purpose?

Thanks
Jim

[michael langman]

I may be wrong, but I think the 7 nad 14 degrees are the same angle. The 14 is called an included angle, which means it cuts 7 degrees to each side of the perpendicular plane, which adds up to 14 degrees.

[Jerry Miner]

Mostly an aesthetic choice, but some like less angle on more brittle/fragile species, more angle on tougher ones. Some router jigs are set up for certain angles.

There are more choices than just 7 & 14. Here is a pic from the Infinity Tools catalog:

Dovetail bits Infinity 6-13-17.JPG

[Doug Hepler]

Some confusion may arise from the fact that DT angles are sometimes given as a ratio, e.g. 1:6 (9.5 degrees), 1:8 (7.1 deg). A 14 deg bit corresponds to 1:4

As long as the DT and pins match the angle does not matter much. Here is a quote from Rockler's website:https://www.rockler.com/how-to/angle...trength-joint/

Some woodworkers recommend using 12° for “coarse work” and 7° to 10° for decorative joints. Lower (7° to 9°) angles are often advised for joining hardwoods, while higher angles (10° to 14°) are recommended for softwoods and even higher angles (14° to 18°) for half-blind dovetails. Here’s the scientific evidence: In 1958, the U.S. Forest Products Research Laboratory tested how dovetails cut at angles ranging from 7.5° to 17.75° in both hardwood and softwood samples fared when the joints were mechanically pulled apart under great force. The study found that, in all cases, “… the dovetail angle made absolutely no difference to the strength of the joint.” These findings support a cosmetic approach for cutting dovetails at whatever angle looks best to you.

[Bill Dufour]

Since the dovetail bits have small shanks compared to the width I baby them. First I rough out the dovetails with 1/4 carbide endmill to remove about 1/2 of the wood. I set it a few 1/1000's shallow.
Bill