I'm a tool guy. I grew up on a farm and learned early how to use, maintain, and repair tools. I learned from my Granddad who raised his family in the depression on a farm, and from my Father who served in the Navy in WWII, then came home to be a farmer. Wood handle tools can have the best head in the world, be it tempered shovel, pick, double bit axe, hatchet or hammer, but if the quality of the handle is poor, you have junk. Quality handles are out there for replacements, and they are not hard to fit properly. I buy mine from Mennonite makers who craft them with select grain hickory wood, no knots or checks. I fit them tightly and with the right cast (angle), and pin or wedge them the old fashioned way. Then I treat them with oils and keep them treated, and protected from the weather.
I am in construction now, and have thousands of dollars worth of tools. Very few of the tools I use for the jobs have hickory handles now. Almost all are FRP and carry a lifetime replacement warranty. I just cannot get the workers to take proper pride in the tools, and this is the best way I've found to solve the problem of broken handles. I keep my good wood handled tools at home and use them here on the farm. I add one or two refurbished ones a year to my shed, usually found with a broken or rotted handle at yard sales and second hand shops. These tools all get refurbished at least annually, some after every job. No rust or concrete is allowed to remain, no cracked or splintered handles. Many of the construction tools are six years old or older, and they look and function as new, though they have been used hard.
Check with Lehman's if you don't have a group of Amish or Mennonites living near you. They usually have craftsmen who make handles, and sometimes smiths who will properly install them. That said, I would not consider buying an axe, hatchet, or other tool with a knot in the handle. Shoddy craftsmanship at best. Unreliable and dangerous at worst.
Codger