I, too, have had little to contribute to these discussions, but this
information may have some value to those who are splicing round leather
belts with metal staples.  I picked this up from my friend the saddle
maker and have made something similar when I was making knife sheaths.

This is a grooving tool that is used to bury the stitching in
leatherwork;
http://www.amazon.com/Seiwa-Leathercraft-Adjustable-Leather-Groove/dp/B004IDQ536/ref=pd_sim_sbs_ac_2 

And, here is a replacement blade:
http://www.amazon.com/Tandy-Leathercraft-Saddlemakers-Replacement-8070-00/dp/B0036W4EMO/ref=sr_1_26?s=arts-crafts&ie=UTF8&qid=1386694137&sr=1-26&keywords=leather+blade 

The blade alone might be held with vise-grip type pliers, to save
a bit of money.  I think this tool, used with a simple guide, might be
safer and more accurate than cutting the groove with a razor blade.

I have no affiliation with Amazon, Seiwa or Tandy.  There are other
sources of leatherworking tools.

Jim Shockey