Sharpening a spine

I'm starting this for my RAT-7 but it applies to any knife I think.

I was wondering what folks use to sharpen the spine on their knives. I'm going back and forth on using my belt sander vs chucking it up in my vise and using a file. I realize that keeping the blade cool is important so I don't want to do any damage to the blade.

 

File. It really doesn't take long if you're only doing a small section for a Striker.

 

Got on my RAT tonight with a file and put a good 90° spine on it. It'll throw a shower of sparks from my 1/2" ferro rod now!

I also ran it over my coarse shop stone to clean up the edge better. After a couple passes on my whetstone and a little stropping she's hair popping sharp now!

 

Looks good.
I like using diamond to take scratches out of knife spines when making knife handles. It works fairly fast and gives sharp corners with a good surface finish on the flat.

 

I use a dremel with a sanding drum. In just a few seconds it's perfectly squared off.