Sharpening questions

R

remist17

Well-Known Member
I am about to finish up my second folder and want to put a nice correct edge on it. Currently I am using a belt grinder and do passes up to 600grit. The edge is sharp and looks like a V. When I compare this to a bought knife there are some differences. The bought knife has a taper and then bumps down to a steeper V. I hope this makes sense.

I picked up a lansky sharpening system and would like some help and guidance.
I have not shaped this blade yet, still have heat treating etc to do. Do I continue with what I have done in the past and basically make a V or is there another way. The Belt sander way seems to take out the degree and takes it from .095” to edge. I may just be completely wrong.

Thanks
 
Can anyone comment on cutting the bevel in? What is the best method or correct. Is it ok that it looks like a capital V? I see others that have steps in the bevel.
 
I think I finally understand what you are asking. Emphasis on "I think". You are asking if your knife should have a full flat grind or a "saber" grind. That is up to you. A FFG is what I prefer always. Yes, from the spine down to the edge, forming a letter "V". If you still need to heat treat the steel, you need to leave the edge a bit thick......020" minimum for carbon steel......010" for stainless (can be less). As for shaping the bevel.....most knife makers use a belt sander or "grinder". 2x72 is the common size.
 
Yes this is what I am trying to ask. Sorry.
I guess when we get the grind done, heat treated, I use the lansky sharpening system. What degree do I use, I was thinking 25
 
Could anyone post some photos of the process of sharpening. I have something in my mind as what I think the process is. I guess I am looking not so much as the sharpening steps but what the blade looks like prior to actual sharpening. My thoughts are you get the blade down to a dime thickness, heat treat , then sharpen the dime edge with a stone or belt. My current blades start at the back spline and taper down to edge. I see all the really nice knives that start at the back spline and taper down and then have another taper at the cutting edge.
If anyone can provide me with a good reference book I would appreciate it.
 
I use a Lansky for a lot of my sharpening. The angle really depends on what you're using the knife for. For my hunting knives I use the 25 degree, and that works well. For most of my EDC's I use the 20 degree. As long as you have decent steel it works well. For instance, most of the Spyderco knives I've sharpened seem to have a factory angle of a little less than 20 degrees
 
remist17 said:
\ My current blades start at the back spline and taper down to edge. I see all the really nice knives that start at the back spline and taper down and then have another taper at the cutting edge.
Click to expand...

I believe he is talking about primary and secondary blade bevels. I am at the same point (ready for heat treat) on my first knife and have been trying to research the same thing. Love to hear tips.
 
View attachment KNIF.pdf
I tried to show what I am talking about in attachment. Some blades seem to be one consistent grind from the top to the edge. Others seem to have a step taper on the bottom. Which is done for a universal knife?
 
I looked at your pic and I'm still trying to figure it out.
so right now where are you at. You have ground the bevels in preparation heat treat to about a dimes width?
If so good then you can heat treat it and after HT you will grind that bevel down thinner to around .015 - .005 or so depending on the knifes intended use. After that then you will take the lansky and sharpen it adding the secondary bevel which is the cutting edge.

I hope this helps this is kind of rookie helping rookie here i have only been at this just under a year
 
This is what I was thinking also. Last time I did a knife I heat treated and then ground sharp so it was just a V and no bevel.
 
When you do a full flat grind (FFG), typically a narrow (.020") is left. This will form the secondary bevel that will be ground in anywhere from 15 to 25 degrees depending on use. "IF" you leave it as the full flat grind with the flat grind tapering all the way to a sharp edge, this will be a VERY sharp edge without much strength as it's only a 2 or 3 degree bevel. Sure would slice a tomato! BUT, the edge would chip so easy. By using the secondary bevel (as shown on the right vertical blade) allows use of 15 or 25 degree bevel for much more strength in the edge.

Ken H>
 
remist17 said:
View attachment 52151
I tried to show what I am talking about in attachment. Some blades seem to be one consistent grind from the top to the edge. Others seem to have a step taper on the bottom. Which is done for a universal knife?
Click to expand...

That depends on you the maker, there are no rules here. I make mostly culinary and make FFG blades and sharpen all of the knives I make or sharpen for others with a slightly Convexed edge which I do on my 2 x 72" belt sander which I take to 600 grit or 15 Micron finish…

If you started with a thiner edge & knocked those corners off of your top edge view picture, that's what my final edges on a Full Flat Grind blade look like. I hope I answered your question or helped in some way?
 
When you do a convex grind with a belt sander do you grind with the edge up so its cutting into the edge like when using a stone? Or do you go edge down like you would with a strop?

Thanks
 
Thank you all, so if I understand correctly I flat grind to .020" heat treat, and then I sharpen that edge with either my lansky sharpening system or my work sharp system. These would put the 25deg edge. Sound about right?
 
OK here is another dumb question., 1084 steel, heat treat to 1450 (non magnetic). So my question: I put the blade in my 2 brick forge and its heating. I check it once in a while and when it hits non magnetic I leave it in for a minute more. Pull it out and quench. I hear people talk about soak time etc. Is this process I am doing wrong ?
 
I flat grind to .020" heat treat, and then I sharpen that edge ...... 25 degree edge
Click to expand...

Yep, you've got the idea. The FFG allows a thin angle to cut/slice, and the 25 degree give strength to the edge.

I have seen a place where soaking was suggested for 1084, but there is a BIG concern about grain growth. I suspect it's better to hold just above non-magnetic for a minute or so, then quench in a fast quench..... perhaps even a brine solution (if you're feeling brave).

Ken H>
 
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