Get yourself one of those edger sharpening plates sold at some leather suppliers, and there is a tool that Weaver Leather sells for sharpening edgers. It's kind of expensive, other places sell something similar to the Weaver tool. You can also fold emory cloth over a rod and use that as a form.
Grit: 1200, 3000, and 5000.
I have diamond hones you can buy from Sharpening Supplies, Inc.
Diamond Machining Technologies, DMT, makes a lot of sharpening tools. Barry King sells the DMT #2, I have both the #2 and #3 hones.
You might want to buy Al Stohlmans Tool Encyclopedia from Tandy, E BAY or Amazon which shows how to sharpen leather tools.
There are a number of ways to sharpen edgers, just start looking for resources and you will find the information you need.
Good Luck!
Mark Clark