I recently purchased the full size:



with the following specs:



What is the best way to sharpen the Ka-Bar on the Spyderco Sharpmaker?  Should I use the triangles set at 30 degrees or 40 degrees, or should I attempt to keep the 20 degree factory edge by trying to hold the 20 degree angle with the stones laying flat?

What angle would be the most durable for all around cutting.  No need to shave hair with this one, but a reliable edge is needed.

Thanks,
Cipo

Dont know about that type of sharpener, I have a Gatco kit.  Anyway inside the box they got an angle guide chart.  I'd imagine opinions on sharpening angles vary, but heres what it says:
* = degrees

11*  Most narrow bevel; produces razor sharp edges.  For Xacto blades, razor blades.  Requires frequent re-sharpening.

15*  Superior sharpness for woodcarving instruments and thin specialty blades.

19*  Fine edge excellent for fillet and boning knives.

22*  Ideal for kitchen cutlery and other high quality knives.

25*  Wider bevel; more durable edge.  Perfect for pocket, folding, hunting and fixed blades.

29*  Widest bevel, lingest lasting edge.  For utility cutlery, carpet, linoleum, electricians and serrated blades.

I'd say based on this chart use your 20*, especially if thats the factory angle.  I believe it may be a bit sharper than the 30*, even if you have to re-sharpen it more often.

If anyone finds fault in this chart or my reasoning, please feel free to correct me.  Always open to feedback.

Hope this helps Cipo

The 40 degree setting is really 20 degrees per side, it's 40 total. So if you sharpen on the 40 degree posision you will get a 20 degree edge which is good for that size knife. I use 20 degrees for just about everything.

Thanks for the info!  You are correct, I checked my SharpMaker and it is definitely 20 degrees each side on the primary setting.  It all makes sense.  Thanks to both of you for the info above.  Now I can sleep at night.

I'd be susprised in the Ka-Bar came with a 20 degree bevel, but maybe.  I'd expect more like 25.  

Often with big rugged type knives on the Sharpmaker, the knife angle is too high (e.g. 25) such that the actual edge doesn't touch the hones.  The symptom is that people swip away at the Sharpmaker for hours with no measurable results.  What people do is to mark the very edge of your knife with a felt pen, then stroke it on the Sharpmaker and look at the edge to see if the marker ink has been removed from the edge or if it's removing steel back from the edge.  

Sharpmakers are not real good for removing a lot of steel if the edge gets real damaged or if you want to reprofile.  I like a Lanskey rig with course and extra course diamond hones for this and use my Sharpmaker for touching up and for thinner kitchen knives.