I wrote this article a few years ago before I was blogging and thought it might be of interest to have here. Fitting an axe handle in this blog post.
First wood selection. The perfect wood is nice straight grain ash fairly fast grown, if it gets more than 6-8 rings per inch it is much more brittle, 4-6 rings per inch is perfect. Having said that a hewing axe like this is nearly always used one handed and the handle does not get the same stress as a felling axe so I would use pretty well whatever wood you have though with a preference for more fibrous species, ash, oak, elm etc.Split your log in half and half again then if it was a fat log you may be able to go down to 1/8th sections.
What you are aiming for is to cut out a bit of wood that looks like this, just a bit bigger all round than the axe of the axe. Draw round the inside of the eye on to the end grain. Grain direction does not matter with ash. I often see it suggested that this orientation with the axe head tangential to the growth rings is good and that radial is bad. I find no difference and all the technical data on ash I can find gives the same info. I think the pics of grain direction that are often repeated probably originate from old American sources and are referring to old growth hickory. In my experience ash is fine either way I more normally end up using ti the other way just because when I split the wood out that ends up closest to the shape I want. Bows are made that way on too.
Next if you have another axe handle you like draw round it on the side profile, or just draw a shape you like. Straight handles are fine, I prefer this shape.
Cut the side profile trying to keep the edges at 90 degrees, at this stage we are not looking for a rounded profile just a nice clean rectangle.