Sharpening Spyderco's At 30° or 40°?

[mathnerdm]

Hey I have a spyderco sharpmaker and I was just wanting to make sure ive been sharpening my spyderco blades properly. Ive been told to sharpen them at a 40° angle although there back bevel is 30°. Is that true? I know the back bevel is 30° but should the secondary bevel be 40°? And does it very on the steel cuz i know a steel like 8cr wouldnt hold an only 30° bevel. Thanks!

EDIT: Heres a fail diagram of what I mean with terrible proportions lol...
---http://www.mediafire.com/?mo759aq57hdm5ts---
If you cant tell, which i dont expect you to, the top one is a 30 degree angle (15 and 15) sharpened using a 40 degree setting only contacting the lower part of bevel. While the bottom is the same degree as the bevel and it contacts the whole bevel. Which is the proper way?

 

[THG]

Your knife doesn't necessarily come with a backbevel. This is something that you can put on your knife if you want to reduce the angle. This will not reduce the angle of the edge itself, though.

Put sharpie marks on your bevels to see where each setting (the 30° and 40° settings) is grinding. If the sharpie marks are not coming off at the very edge of the blade, then your actual cutting edge is larger than whatever setting you have it at.

 

[HoosierQ]

Here's the deal. I am a huge Spyderco fan...have too many to enumerate. However, their bevels are not real precise nor are they consistent. Sal Glesser states they come 30 degree inclusive from the factory but I have not found that to be the case. What will happen is that at 40 you get one side doing a micro bevel and the other side indexing along the whole seconcary bevel. With 30 degrees, you might get one side to index on the whole bevel and the other side doing a back bevel.

My most recent Spyderco, a Manix 2 XL, was very even.

What I like to do with just about all factory edges is freehand them down to lets say 27.5 degrees inclusive. Then I can easily use the SharpMaker to put and maintain a microbevel on there. I have some set at 30 and others at 40. I use my Spydercos a lot so I set them at 40 and then put them on the SharpMaker for frequent touch ups. So I basically go about it the opposite way. I sort of get the back-bevel out of the way first and put the final bevel on last. I love the SharpMaker but it is not a tool that will remove a lot of metal quickly. Taking a crisp 40 degree bevel and knocking that back bevel down is going to take a lot of time on the brown/course stones to be effective...to improve slicing performance. I am talking hundreds and hundreds of strokes here on anything but the softest of steel...which Spyderco is not. So I don't use the SharpMaker for removing metal in any volume. Once you get the bevel indexed, I think there may be nothing better than a SharpMaker for touching up. It is so easy and quick you won't hesitate to do it so your knives will always be sharp.