I am having a very stressful day regarding my L70 wizard that has gone nowhere specific for about 3 years, and just as I gathered all the materials to craft the Wintertusk hat for him in the Equipment table, low and behold he can craft anything but the hat!
you need to use the Grizzleheim crafting hammer to make the WT gear (enter the doorway surrounded by rune stones by the fishing instructors in the GH commons area). if you look at your crafting screen for that item, you will see the GH icon instead of the equipment crafting table.