Damn, that sucks you splintered one. It really shouldn't have done that. It's never happened to me when filing on one but it might be a difference in the bone i use. I buy my bone off eBay & it is nice bleached white bone. If you have to, you can make a new piece. I broke a piece when making a set for the W&B I made bone scales for when I decided they were still too thick & broke one when punching the pin out. I made another piece & then I made them thinner.
http://straightrazorpalace.com/razor...ml#post1422154