A log saw machine includes a first arm, a second arm parallel to the first arm, a shaft having a first end and an opposite second end, and a circular knife fixed on the shaft. The first end of the shaft is rotatably installed on the first arm. The second end of the shaft is rotatably installed on the second arm. The circular knife is positioned between the first and second arms, and the plane of the circular knife is parallel to the extending direction of the first and second arms.

Nonmetallic tools such as rotary bits, circular blades, and scything tools are described that may be suitable for removing cured flexibilized epoxy gap-filler materials from gaps between soft composite materials. The nonmetallic tools may be formed from various plastic or composite materials that are sufficiently hard to cut through the gap-filler material while being sufficiently soft to avoid damaging adjacent areas of soft composite materials. Methods for using the nonmetallic tools may include attaching the nonmetallic tools to a suitable machine-driven tool and contacting the nonmetallic tools to a material to be cut, shaped, or drilled.