Finishing the Edge

S

sharp21

Joined
May 6, 2009
Messages
12
After grinding the bevel so that there is still 0.020 or so left of the edge, then finishing the knife, what is the best way to finish the edge? Is it a secondary bevel that is sharpened or is the flat grind just carried down?

I am filing by hand so I don't want to finish up to 600 grit, then heat treat, THEN have to go back to the file to put an edge on now that the steel is hard!

The reason for keeping that bit of thickness is so that the edge doesn't warp during HT correct?

S.
 
You don't need a 2 x 72 grinder to do the final edge. Do you have access to at least a 1 x 42 or 1 x 30 belt sander? That would definitely make things easier. If you do, you can do the final edge from your .020" finish spot pretty quickly.

I start with a 150 ceramic belt and hold the knife edge down at roughly 15 degrees, then starting at the ricasso and going to the tip I make smooth passes on the grinder. Don't go too fast, but don't slow down too much or stall your movement to keep the edge consistent. I do 4 or 5 passes per side always making sure to keep the total number of passes per side the same. Keep going until you get the edge fine enough that a burr develops on one edge, then go to 220 grit and start by knocking the burr off. Produce another burr with the 220, then repeat the process with 400. After that I polish on a compound loaded paper wheel for a nice polished edge.

This is just the method I use when I finish a knife. It may not work for you or be how you want to do. I've had good results.

Others might have more suggestions for you if you don't have access to any power tools. I've never finished a knife's edge by hand so I'm not sure.

Good luck, pics when you're done:thumbup:
 
Absolutely no sander. I work at sea so just use what is available onboard.

My first attempt turned into scrap at this stage. I ended up filing a big concave in the blade...

I've filed it fairly close & am going to heat treat with a welding torch. I'll try to sharpen it up after that & see how it goes.

Was I correct though that the reason you don't go all the way to an edge before heat treating is because it might crack? What do you do about a scandi grind then?

Thanks for the help
S.
 
I should shut up as I've not done a scandi grind. To me it's just a very large secondary bevel and much more metal to deal with when resharpening.

Yes, you leave it thick before heat treat to reduce the chance of cracking.
Someone will show up that knows what their talking about.:D
 
Sharp -

Go to the galley and get one of their sharpening stones. Best if they have a triple stone(three grits). It'll take a while but you should be able to cut in a fine edge with that alone.

or

Sheets of emory cloth from the machine shop. Tape them to a flat piece of flat steel.....
 
Make one of these puppies and use wet/dry sand paper or emory tape....

stropbats.jpg

backingpaddle.jpg
 
Sharp: That's why you don't work on knives when your tired at 0400.

One reason not to take it to the edge is that you don't want to work on a sharpened edge. Also, it can affect the geometry. Some kitchen knives will grind flat to the edge to get a thinner blade that slice veggies better. On a working knife you would want a thicker blade with a secondary bevel for the edge.
 
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