Corners/flats on the sharpmaker

[ratdog]

I've been tring to get push cut sharp on my sharpmaker at 30 degrees and using the corners. Is this possible? Or do I have to use the flats to get push cut sharp. It's so hard to keep the blade flat on the flat sides where sometimes I think I'm doing more harm then good.

 

[WadeF]

The flat sides put less pressure on the edge and should give you a better edge. The corners may role some edges over if you apply to much pressure.

What do you mean it's hard to keep the blade flat on the flat sides? You always keep the blade straight up and down when you use either the corner or the flat. You are repositioning the stones so the corner or flat faces inwards when you are using them right? It's a bit hard to explain in text.

 

[Cougar Allen]

 

[Dog of War]

I've been tring to get push cut sharp on my sharpmaker at 30 degrees and using the corners. Is this possible? Or do I have to use the flats to get push cut sharp. It's so hard to keep the blade flat on the flat sides where sometimes I think I'm doing more harm then good.

IMO it's imperative that you use only very light pressure with the Sharpmaker or any similar v-sharpener if trying to get a very fine edge.

This is especially so if you're using the corners, but also using the flats. As you point out it's difficult to keep the edge on the flat .... just the slightest bit of left-right error in the way you hold the blade and now you're sharpening on the edge of the rod's flat side which makes for a very small area of contact and thus potentially a great deal of pressure on the edge. If you look at the way metal is left on the rods when using the flats you usually see a lot more at the edges of the flats rather than in the middle, which tells you this is what's happening .... also I've found some Sharpmaker rods where the flats aren't flat, instead a bit hollow (and irregular) in the middle.

All of which supports the conclusion: never use heavy pressure when using a Sharpmaker or similar, and continue to use lighter and lighter pressure as you get closer to the finished edge you want. The last few strokes I make are so light you would think no metal is being removed at all - it could be that this burnishes the edge as much as anything - but the difference in sharpness this makes can be huge.

 

[Vorpal Blade]

IMO it's imperative that you use only very light pressure with the Sharpmaker or any similar v-sharpener if trying to get a very fine edge.

This is especially so if you're using the corners, but also using the flats. As you point out it's difficult to keep the edge on the flat .... just the slightest bit of left-right error in the way you hold the blade and now you're sharpening on the edge of the rod's flat side which makes for a very small area of contact and thus potentially a great deal of pressure on the edge. If you look at the way metal is left on the rods when using the flats you usually see a lot more at the edges of the flats rather than in the middle, which tells you this is what's happening .... also I've found some Sharpmaker rods where the flats aren't flat, instead a bit hollow (and irregular) in the middle.

All of which supports the conclusion: never use heavy pressure when using a Sharpmaker or similar, and continue to use lighter and lighter pressure as you get closer to the finished edge you want. The last few strokes I make are so light you would think no metal is being removed at all - it could be that this burnishes the edge as much as anything - but the difference in sharpness this makes can be huge.

Agreed.

Also, it's possible the edge bevel is not steep enough for the stones to be making contact with the edge. The stones could be making contact with the shoulders of the edge bevel. In that case, reprofiling to a steeper angle than 30deg. is necessary.