Friday, March 15, 2024

Crafting a Turning Saw (Bow Saw)

Fabricating the Frame

A turning saw, often likened to a miniature bow saw, shares similarities with a coping saw but boasts a larger frame typically around 12 inches in size. Tools for Working Wood offers a turning saw of exceptional quality for approximately $180, slightly beyond my intended budget. However, they generously furnish both the components and comprehensive blueprints for constructing one's own saw, a project well-suited for most woodworking enthusiasts. Accompanying the parts and plans is a detailed set of construction notes, facilitating the process significantly.

 

To commence the project, I procured a set of pins and three blades from TFWW, intending to fashion my own handles owing to the presence of a lathe in my workshop. The plans, when printed on legal-size paper with scaling disabled, yield accurately dimensioned templates. These templates, including those for the cheeks and stretcher, necessitate adherence to straight-grained stock due to the substantial stress these components endure. Once the templates are affixed to the chosen stock using an Elmer's glue stick, they serve as guides for cutting. Any residual adhesive can be easily eliminated with a wipe of mineral spirits, especially since sanding the wood is a subsequent step in the finishing process.

 

Minor deviations in the cutouts, as encountered in my own work, need not cause undue concern given the forgiving nature of the design. While alignment of the pinholes is desirable, the overall precision required is minimal, given the primary function of the saw—to provide blade tension and support during cutting operations. Any discrepancies can be remedied through carving or sanding adjustments during subsequent stages of assembly.

In the next phase, these roughed-out components will be transformed into finished parts, including the creation of knobs and a winding toggle.

 

 

Assembling the Turning Saw: Completing the Construction

Following the shaping of the frame components, attention turned to the fabrication of the handles and the winding toggle, depicted in the accompanying image. Regrettably, photographing the process while utilizing power tools, including the lathe, proved cumbersome, necessitating a descriptive narrative in lieu of visual documentation.

 

The toggle begins as a ½” diameter cylinder, easily fashioned from offcuts derived from the saw material. After rounding the ends and forming a cove near one extremity to accommodate the tensioning strings and allow for pivoting under tension, the toggle is completed by flattening the opposite end into a paddle shape. Multiple methods exist for achieving this, but I opted for expediency, utilizing a stationary belt sander for a swift process lasting a mere 60 seconds.

 

Similarly, the handles, fashioned from walnut for their durability, were swiftly fashioned on the lathe. A ¼” hole bored into one end accommodates the blade pin, while the handle's simplistic form lends itself to a straightforward turning exercise, with precision being of secondary importance. After the completion of both handles, the blade pins are securely affixed in place using a slow-setting epoxy, ensuring a robust bond. Any excess epoxy is carefully managed, as the pins are pressed into position, exploiting the grooved design to facilitate adhesion.


For the finishing touch, a diluted boiled linseed oil is applied in two coats, providing both protection and aesthetic enhancement. With the components prepared, final assembly entails inserting the stretcher into the mortises and affixing the blade to the pins, akin to a coping saw. Following the recommended stringing method—utilizing 20lb (or stronger) braided fishing line—the toggle is employed to tension the blade, with personal discretion guiding the extent of tension applied.  The string/line is also available on the parts link above, but I had a fishing rod that used the braided line.

 

Acknowledging the subjective nature of tension requirements, experimentation and familiarity with the saw's nuances are recommended. As I acquaint myself with its operation, I intend to refine my understanding of optimal tension levels and share insights gained from practical experience. In conclusion, embarking on this endeavor proves to be both enjoyable and rewarding, offering a cost-effective solution to one's sawing needs.

 

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