Backing Tool Head for Bookbinding

NOTE: This model only includes the toolhead, not a dedicated handle

There are several historical methods for backing/rounding during the bookbinding process, such as backing hammers. This tool head mimics existing "Backing Tools" found online (tips on tool use provided at the tool's website)
https://koutsipetsidis.wordpress.com/2025/10/12/backing-tool-kaschiereisen/

While this design mimics the general shape of the linked Dimitris Koutsipetsidis tool, it is not a 1-to-1 duplication of the tool's curvature, teeth size, width, or teeth spacing. The tool itself is said to be similar to a German Kaschiereisen / the Finnish Falsbanker, combining the functions of tools like the frottoir and grattoir.

Two toolhead versions with smaller or larger tooth sizes have been provided for your convenience. Due to the repeated hammering used in the bookbinding process, a 3D-printed plastic handle may get dented or cracked and is not recommended

A circular space has been made on the back of the tool head in order to add a suitable handle, such as a sawn off section of a wooden broomstick
- The circular space has an OD of 23.50 mm (~.93 inches) and a depth of 5.5 mm (~.22 inches)
- The central post, which could be bonded to the handle with adhesive, screws, or other fasteners, has an OD of 6 mm (~.24 inches), an ID of 4 mm (~.16 inches), and an inner cavity depth of 7.50 mm (~.30 inches)
- A hexagon for gripping the tool head during assembly surrounds the circular space and is about 27.50 mm wide (~1.1 inches)

The example tool heads shown here are made of PETG (typically more chemically resistant when working with adhesives/solvents) with 4 walls and 25% infill, oriented with the flat face of the hexagon/tooth structure touching the build plate, and tree supports for the circular cavities (shown below)

POTENTIAL IMPROVEMENTS:
- Adjustments to match an existing off-the-shelf tool handle
- Dedicated 3D-printed handle/hammer combo
- Optimizations and methods for removing glue from teeth grooves
- Optimizations to remove any need for supports