Based on my experience, these mandrels are perfect for cutting holes in plywood and plastic .They fit securely into the hole saws and don't slip or wobble during use. The industrial AND scientific quality of these mandrels is impressive. They create clean and precise cuts without any jagged edges. The only downside is that they are a bit pricey compared to other hole saw accessories in the market. Overall, I highly recommend these mandrels to anyone looking for top-notch quality and performance..