what is the method to sharpen a double bit axe?
Welcome to the forum, Kenneth! :)
In my opinion the Tormek Tool Rest will be suitable. It has a large surface (3½"×4¼"), which will permit steady positioning of your double bit axe towards the stone.
Feeling axe has usually an edge angle between 30 and 40 degrees. The edge angle can be set and measured with the Tormek Angle Master.
Jan
P.S.: Sometimes one bit is designated for cutting roots through dirt and therefore its edge angle is larger.
Welcome, Kenneth. The link below is to "An Axe To Grind". It is put out by US Deptartment of Agriculture and is quite informative. It has a section on sharpening that starts on page 28 of the book (pg34 of the pdf).
http://www.google.com/url?sa=t&rct=j&q=an%20axe%20to%20grind&source=web&cd=1&ved=0CB8QFjAA&url=http%3A%2F%2Fwww.fs.fed.us%2Ft-d%2Fpubs%2Fpdfpubs%2Fpdf99232823%2Fpdf99232823Pdpi300.pdf&ei=nJlKVYOID8nEggSdxYGICw&usg=AFQjCNGY2a233TBsiGOyQSPGhDV0erePag&sig2=kcOBJ1R3D81KVy01QHF3Gg
There is a thread in the "Hand Tool" subsection of the forum that has links to other axe and logging information. It can be found by using the following link.
http://forum.tormek.com/index.php?topic=2494.0
Thank you for the helpful replies. The y gave a lot of information.
KenB