Hera are small Japanese tools useful for a variety of scraping, lifting, and delaminating tasks. They are common in paper conservation. Tonkin is a dense, flexible and strong type of bamboo that handmade fishing rods are made from. More about Tonkin. Heat treating increases the elasticity of the bamboo.
Even so, hera with very thin and flexible tips can wear and can crack, so they need to be maintained by sanding, carving, reducing the width, or even shortening. Once you have the skills to make a hera, they are easy to maintain. If you want to keep things simple, shape it with your Olfa knife, sand it with 220 grit, then finish it with 600 grit. More tips on shaping bamboo.
These blanks are roughly 6 inches long, and 1/4 – 3/8 inch wide. If you want to make two narrow hera, you could split a wider blank. Just ask me for the widest one I have. Making your own tools to the exact size and shape you need is rewarding and satisfying.