Good point. I was assuming you could turn the speed down on a bench grinder (I don't have one myself to know yes/no). Heat could definitely destroy temper in some metals (I'm thinking spring steel). I don't know about something solid like an ax head. I remember grinding a "waist" in a flat spring from one of my firearms to lighten it's springiness (the loading gate spring from a lever action rifle) - I was grinding that with a Dremel tool and holding the piece in my hand, not in a vise or with pliers. As soon as I felt any warmth (only took a few seconds to develop), I would dunk the piece in a cup of water to cool it. I was worried about ruining the temper of the spring. Same thing may go for an ax head, but since it's not a spring, I don't really know.

Indeed destruction of temper is why grinder is never recommended. Belt sander can work but I don't have one!

I've never seen a bench grinder that could turn the speed down enough to not potentially cause heat issues. The variable speed bench grinders I've seen go from "crazy fast" to "MWAH HAH HAH HAH!"

I don't know how I'd live my life without my Kalamazoo 1" x 42" belt sander!

NEVER use a bench grinder on an axe. Axes (at least good ones) are differentially tempered (soft head - harder edge) and are easily subject to damage by heating. Use a file and stone, an old pedal powered wheel (often used with water), a wet wheel grinder (good ones are now available) or a square wheel grinder (like a belt sander but slower). A belt sander works well if you can slow it down or work bare handed and keep the head cool.

The "fan" works well on a Dayton pattern head, like the double bit you used. As you figured out, it does not work on all head patterns, but the idea is there, the cheeks need to taper up smoothly. For many years axe heads were made with extra meat in the cheeks to allow each owner to cut it to his use. Many old axes were never cut down and are far to thick for anything but splitting. The USFS information does not say so but they are cutting the head for dry, South Eastern hardwoods(IIRC). It is a good general grind, but not universal. My Gransfors Bruks Forest Axe is designed for green conifers and has a different cheek shape (deeper and more narrow). It is unfortunate that guides are not available (that I know of) for various purposes.

Respectfully,

Jerry

Thanks for the insight. I scoured the web for "to scale" guides for other purposes. I have continued to file exactly as you described - to thin by creating a smooth transition. More photos soon!

Kevin,

I have never seen a guide for other uses, only seen (and felt) the results from axe men who knew their stuff. I did lumbering in the Rockies and the old guys could show you a lot. Their work is similar to what I see from Gransfors. Maybe I should make one off my axe before I ever sharpen it.

Looks like you are doing a great job. What I would expect from your other work. Thanks for the pictures.

Respectfully,

Jerry

As I recall some double-bit axes have different profiles on the two edges, one being thinner for different cutting requirements. My favorite axe is a double-bit cruiser. It's an older axe with good steel and a harder edge than you find on many of the current axes. Just don't hit any rocks. I have and older axe hear with a big chip from hitting something not intended. Those harder edges will chip out.

/cruiser/ No affiliation, just a good write-up re Double-bit Cruisers.

My favorite axe-type tool is a Pulaski-cutting capability together with grubbing capacity. It is a really fabulous tool on the fire line

Russ,

It is common for a double bit to have two different profiles, as shown in the USFS book that Kevin got his information from.

The "Cruiser" you posted is not the same as the terminology I learned. My use of cruiser is the same as the definition in yerteryearstools:

cruiser: one who estimates the potential lumber yield from the standing timber on a specific tract of land and may mark out routes for accessing the area. (also: estimator)
cruiser’s axe: a small version of a double bit axe designed to make markings by slashing the bark such as when blazing. (also: timber cruiser’s axe)

See: http://www.yesteryearstools.com./Yesteryears%20Tools/Glossary%3A%20Axes,%20Edge%20Tools,%20etc..html

Typically a 2 to 2.5 lb head on a 27" or 28" handle. They would have been typically ground the same on both sides since it was primarily used for blazing trees for removal. If yours is like this, it is also my favorite axe for most things.

Respectfully,

Jerry