Do vegans use woolen clothing? I don't think it hurts the sheep to be sheered, probably makes them feel cooler for summer.

Though I'm sure there are exceptions, I don't think vegans would wear wool. A vegetarian would, yet vegans don't consume animal product even if the animal would not normally be hurt from it being taken, such as milk or eggs. Where I live, there isn't much population density, i.e, while I live in a town there is large fields and farms around us. The cows aren't hurt while milking, I would know since I have held a job at a local farm. However, big companies tend to treat their animals poorly, even animals that are not killed when harvesting their resource. If I buy locally, I can avoid this since the farms are regulated by law, though I'm not sure that's the case elsewhere. The reason for this is that in many farms today, it is more like a place for mass production than a farm. Milk cows (which have separate breeds than beef cows. While you can eat a milk cow or milk a beef cow, their breeds are specialized for one or the other so they aren't really ever used for both) are often crammed into small, dirty spaces for life with minimal resources. They can also be given growth hormones that are harmful to their health and wellbeing, and sometimes physically abused. Same with hens that lay eggs (again, separate breeds.) I would assume that vegans would decline to wear wool out of caution for similar circumstances for sheep.

No, they don't. True vegans won't eat, wear or use anything from an animal.