Making Spokeshave Blades

To date, I have made spokeshave blades out of O1 steel only. It makes a great blade and it is easy to heat treat at home. I begin with Starrett precision ground flat stock. An 18-inch length will yield four blades. I use one-eighth thick stock, five-eighths wide. Shaping the blades can be done entirely with hand tools, the most important of these being a good hacksaw and a few assorted mill files. Scribe your lines carefully on your blank stock, saw close-but just outside-the lines, then file down to your lines. It is slow work, but reasonably precise. After obtaining the proper outline, drill and tap each blade for a 10-32 thread rod post. This allows you to use the posts to help control the blade when grinding the bevel. Heat treating can be done with MAPP gas (for hardening) and a toaster oven (for tempering). The word on the street is that toaster ovens maintain a more even temperature that the standard kitchen oven. Check out Ron Hock's website for "Some Thoughts on Do-It-Yourself Heat Treating of Tools Steel."

After making 20 blades by hand for a class in spokeshave making I taught in 2001 (though I did have the professionals at Hansen Balk in Grand Rapids do the heat treating for me-great guys), I decided to "apprentice" myself to a machinist to make the next batch. Fortunately, I know a very patient machinist, fellow Michigaloot John Black.

I journeyed to his basement shop one Saturday to make 35 blades for my next class at John Wilson's Home Shop this February, 2002. The labor-saving device at the heart of our work was a Fairbanks Ward Drilling & Milling Machine. John did his best to teach me some of the basics, and I was pleased with my own progress: I graduated from broom engineer to handle puller in a single day. John was probably grading on a curve.

We began by cutting the 18-inch bars three at a time. John screwed an angle plate to the top of his bench about 4.5 inches from the edge of his bench vise. While not the most precise fixture, it did promote fairly consistent results. Using the edge of the jaws as a guide, I cut the blanks just a little longer than their finished length. We used a magnetic base atop the jaws to hold the stock in place correctly while tightening the vise. A neat trick.

The next step was to drill the holes for the posts. But before this could be done, the mill needed to be set up. The first blade was placed in the vise on the mill bed. John then put an edge finder in the collect to find the edges of the blanks. As soon as the finder touches an edge, it goes out of alignment, as shown in the adjacent photo. Subtract the radius of the finder and you have your edge.

Knowing the edge, you can find the precise center for the post holes. But it seems no machinists I have observed can simply drill a hole. No, they make a production out of it. They begin by making a small hole and chamfering it. Then they drill again to the final size using a larger drill. John showed me how to "tap" the chamfer drill down a few times before advancing it through the blade. Proper "tapping" countered the drill's natural tendency to "skate" off-center. The chamfer helped guide the second drill into center of the hole. It also made tapping (cutting the threads in the blades for the posts) easier and it eliminated the need to remove the burr which would occur without the chamfer.

And now for the fun part: milling the blades. I "hung" about 20 blades on a drill in the holes we had just made in order to align them. John then carefully placed them in the vise. He used a small raw-hide mallet to tap them down on the parallels used for final alignment. This ensured that the two notches cut on either side of the blade were relatively consistent across all the pieces.

At last the chips begin to fly. Although it is much, much faster than filing by hand, we did need to make several passes with the cutter to remove all the stock. A larger mill could have done it in fewer passes.

The last pass before milling off the ends of the blades to their final length.

We then tapped each blade. This we did by hand. A simple tapping fixture was made by drilling and tapping a 10-32 hole square to the bottom face of a piece of Lexan plastic. The plastic fixture was used to ensure that the tap stayed perpendicular to the blade.

The previous day, John made a jig out of aluminum to hold the blade at the proper angle so we could cut the 30 degree bevel on what will become the cutting edge.

Cutting the bevel. Look closely and you can see that the first third has been cut.

The apprentice sleeps while running the mill. He has also failed to roll up his sleeves. Good help is hard to find.