Monthly Archives: May 2014

Making Spill Plane Blades

I currently am in the process of making a small batch of spill planes, and started with the blades.  I am a tool and die maker by trade, so I made an agreement with my employer to use a CNC milling where I work.  ( No, it was not free.) The blades are O-1 tool steel, and is available as flat ground stock in the size needed. (1/8 x 1 1/4)  After sawing the blades at the correct angle,  the blades were clamped in a fixture that allowed me to machine both the tang shape on one end, and then with the fixture tilted to 25 deg. to machine the bevel on the cutting edge.

The blades were then heat treated at my own shop to a hardness of 60-62 Rc. This was done with a pair of MAP torches, one on each side of the blade, which was held with a pair of vice grips.  After heating to cherry red, the blades were immediately quenched in oil.  (This operation was done outside for obvious reasons.)  After cleaning off the oil residue, the blades were tempered in our kitchen oven.

I then took the blades back to my work, and engraved the logo on the tang end.  The blades are only hardened on the cutting end, so machining the logo was not a problem.  I could have done this at the time of machining, but I wanted to see how flat the blades stayed after heat treating, in case they needed to be surface ground, in which case the logo would have been lost.  They stayed flat within .002″, which can be lapped out with a course water stone.  Surface grinding was not needed.


The next step will be to lap the backs and bevels flat, and hone the edges razor sharp.  I have a nice stash of quarter sawn beech for this project, and plan to make all of the planes out of it.  These spill planes are on sale now.   I still have a couple from the last batch in maple and beech.  See my spill plane post for more information.