Chisel Back Flattener/Preparation Kit
Polishing and flattening the back of a chisel or plane iron must be performed during the initial setup of all new edged tools. The back of a chisel or plane iron constitutes half of the total cutting edge, making flattening essential with each new blade to achieve the sharpest tool. A flat plane iron back allows the chip breaker to seat properly, while a flat chisel back produces an edge that can serve as a reference surface, guiding the tool much like the sole of a plane. Once the initial polishing and flattening are completed, there is no need to repeat the process.
Typically, this procedure is carried out using diamond stones, water stones, or sandpaper adhered to glass. However, these sharpening media can be expensive and require maintenance (water stones need flattening, and sandpaper needs replacement). The process can also be messy, as water and sandpaper require water to carry away the swarf, and sandpaper may cut slowly, while water stones tend to clog and glaze over.
To address these concerns, we developed the Chisel Back Preparation Kit, offering a cost-sensitive solution that is fast and effective for the initial setup of edge tools. The kit includes a 5” x 11” piece of dead-flat 5/16” thick float glass, a selection of 5” 3M PSA sanding discs (2 each of 320 and 400 Cubitron II discs, and 2 each of 600 and 1000 grit PSA aluminum oxide discs), and 16 each 1/2” diameter urethane PSA bumpers.
The 5/16” float glass provides a dead-flat reference surface, and the urethane bumpers, placed on all corners and in the middle of both long sides, prevent the glass from sliding around while elevating it above your work surface to keep it clean. The Cubitron II PSA discs cut fast, last a long time, and require no lubricants. Starting with 320 grit and progressing to 400 grit is typically aggressive enough for most flattening operations. A standard 3/4" or 1" chisel can be flattened in seconds. If additional work is needed, rougher abrasive discs can be ordered separately HERE.
The flattening operation is completed with 600 and 1000 PSA aluminum oxide discs. Although the aluminum oxide discs do not last as long as the Cubitron II, they are very inexpensive to replace HERE. Once the back face reaches 1000 grit, the final polishing can be achieved by stropping on our Drill Press Sharpening System, resulting in a razor-sharp mirror finish.
Our Chisel Back Preparation Kit has proven to produce chisels and plane irons that are as sharp and flat as any other system available, all at a fraction of the cost.
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