Buddy, I really think you need to reconsider the materials you're using to TRY to grind on. Something like a wooden shower curtain isn't meant to withstand any form of pressure what so ever. It is really inexpensive to just go to Home Depot and ask someone how to secure a long metal pole so that it will not move around when you try to grind it. Another way to find out how to make something to grind on, go to www.ccs.com and buy a book that teaches you what materials you need to create something to grind or just go to the library. One last thing and I'll shut up. The fact that you started your question and concern with grinding being hard shows that you are either giving up or you want some simpathy. Now I'm not saying you're a wimp but nobody likes someone who tries something only a couple of times and then quits. Those kind of people are known as Nancy's and they can just die and fall off of the earth because they're worthless. Use the tools around you to get were you want to get and get want you want to get. Try hard at something, and I mean very hard, before you ask another person for assistance.
Good luck.

PVC Pipe works for me

sympathy not simpathy...***

PVC is really good, but after a while, your plates will either rub off on it, or it will rub off on them, and you'll have to hit some real rails or curbs to get your plates back in immaculate condition.

I think I just commented twice...because i meant to click something, and i accidentally hit the "Comment!" button...sorry.

---Alex