If I may; Sometimes they do not have to be straight enough, just big enough and SOLID enough to get what you want out of it. You would be surprised what you can get out of a small tip. Quite a few tips were two parts so they did not have to be but so straight. I have had many nice looking racks, as far as tips go, that made no tips. I have heard that bone was also used for tip but I have yet to see a bone tip or find a piece of bone that would work.
My 2CW, Tim C.