I've been planning to touch up some very old models of mine, who've fallen into a particularly dreary state. Most have had their spears or swords fall off at some point, so my first mission is to build some more. I'm wondering what materials I should use for the spear/pike shafts for some of the Goblins and Uruk-Hai.

Also what diameter is good for LOTR scale? And how should I make the spear heads.

most of the time I use some metal wire that is just the right size.
And I am too lazy to make spear points, so I just sharpen it up a bit so it looks like a point.

Use gripping beast spears, they are in perfect scale and very cheap