Questions, first time using a Shapmaker

A

abnk

Joined
Oct 4, 2010
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15
Hi all:


First off, thank you for the shared knowledge in this forum.

I purchased a Spyderco Sharpmaker and after reading the book and watching the DVD, I tried sharpening two cheap knives (one serrated) and the blade on an old Gerber multi-tool.

Question 1: With all three, I ran into the same problem with grinding off the tip; the Gerber being the worst. The tip on the Gerber looks like a micro flat-head screwdriver. I read this, but it doesn't really address the Sharpmaker. Any tips (pardon the pun)?

Question 2: I spent almost two hours on the first knife and while it could slice paper OK, I could not get it to easily slice a very ripe tomato. With the other two blades, I had better luck. I tend to blame myself before the equipment, but could it be that the metal on this blade does not take a good edge?

Thanks in advance.
 
Greetings Abnk: Depending upon the factory grind angle and blade hardness, it may take quite a bit of time (hours) to reach the 30 or 40 degree fixed angles of the Sharpmaker rods. When drawing the blade across the rods, do not let the tip slip off the rod. Stop short of drawing the last 1/4 to one half inch of blade across the rods. Treat the last 1/4 to 1/2 inch as a separate blade. Use only the flats of the stones on the last fraction of the blade tip. This will limit the tip rounding effect of slipping off the corners of the rods at the end of the stroke. Be patient. Precision and CONSISTENCY will pay off with a uniform bevel that is easy to maintain. The first use, especially when reprofiling may take a long time. You may wish to use the Sharpie marker trick to see exactly where the rods are contacting the blade. There is a short learning curve of a few knives that is often needed to develop precision. OldDude1

http://www.youtube.com/watch?v=mvl-Y5bZwtw Sharpie marker video link Youtube
 
abnk said:
Question 2: I spent almost two hours on the first knife and while it could slice paper OK, I could not get it to easily slice a very ripe tomato.
Click to expand...

While it might be a problem of edge geometry, when I encountered this same issue I discovered that tomatoes respond better to an edge that isn't so well polished. It needed some 'tooth' to deal with the smooth hard skin of a tomato. (Think how effective a $3 Ginsu knife can be in this situation. That's why they work so well.) This is one reason for using a separate smaller knife (paring knife) for vegetables. While I want my large chef's knife and carver to have an extremely well polished edge, I want my paring knives to be less so. Tomatoes can be cut with an extremely sharp knife, (and I mean really, really sharp,) or with a toothier, almost micro serrated edge. The Sharpmaker doesn't quite produce that super duper sharpness needed for tomatoes, although it's my 'go-to' sharpener in the kitchen as it works so well for everything else. :thumbup:

Try giving that knife a few strokes back on the brown stones, then try slicing the tomato. If that doesn't resolve the issue, then the problem is the edge geometry of the knife and you'll want to re-profile it.

Stitchawl
 
Thank you, gentlemen. I tried another inexpensive blade last night, a small Victorinox knockoff marketed as Winchester. It took me almost three hours, but I got it sharp enough to shave hair. I managed to not round the tip (sharpened the tip by itself on the fine stone only), but I lost a bit of belly curve. Perhaps because I was pulling the blade back parallel with the table?
 
abnk said:
Thank you, gentlemen. I tried another inexpensive blade last night, a small Victorinox knockoff marketed as Winchester. It took me almost three hours, but I got it sharp enough to shave hair. I managed to not round the tip (sharpened the tip by itself on the fine stone only), but I lost a bit of belly curve. Perhaps because I was pulling the blade back parallel with the table?
Click to expand...

Theoretically, you should get even wear throughout the entire edge since with every stroke, you're taking off the same amount of metal from handle to tip. I'm thinking you're using different amount of pressure at different places or not grinding as much at the base and the tip of the blade.

I know you were trying to avoid rounding the tip. This is the main reason I don't use the corners at all. I only use the flats and my stroke is as such:

I start at the base of the blade, run the blade straight down for about 1/2 to 1/3 inch. Then I start pulling it through while slowly tipping the knife. I end with the tip of the blade at the bottom middle of the flat surface and the knife is at a 30 or 40 degree tilt, depending on the angle of the blade towards the tip. I don't let the tip go off the edge.

I hope that made sense. ;) I made a number of posts regarding the Sharpmaker. Do a search and take a look. It's a little different take from the manual or the DVD but it should help.

EDIT - found a few posts. Take a look:

http://www.bladeforums.com/forums/showpost.php?p=8712748&postcount=9

http://www.bladeforums.com/forums/showpost.php?p=8672150&postcount=18

Good luck,
 
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Thank you, Dan. I actually read those posts yesterday and I used your method of multiple strokes per side, instead of alternating every one, last night. It makes sense and worked well for me.

I will be more careful with the amount of pressure I apply. I am probably applying too much.
 
I am almost ready to start learning the best methods for Sharpmaker too. Will watch this thread.
 
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