Gypsy moths and their caterpillars eat and kill plantations. Often in springs, those spongy moth nests appear on plants, especially on trees. The caterpillars inside feast on the beautiful greens till the plant is killed. Here is an article about it: 
https://tompkinsweekly.com/articles/what-to-do-before-before-spongy-moths-damage-your-trees-irreplaceably/
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There is one little tree in the barrier in between the lanes on route 128. It is a little over one meter tall. Early in the spring, it was covered with those spongy moth nests. It was very scary to look at. 

This sharpening method for drill bits and router bits is taught by John Cameron, fine cabinet maker. After several uses of a drill bit, find a very fine file or a diamond stone, slowly file against the top surface of the drill bit until the rust or the unevenness is gone and the tip reflects a little light. Do not tilt the file or stone.