Sharpening - don't know much about it

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sladeblade

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Jul 25, 2013
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Hi Folks,

So I'm brand new to this whole knife making thing and I was wondering how one finishes an edge on a blade. I'm using D2 and I've ground it down to about a dime width and will be heat treating it soon. I did a flat grind (or at least tried to! haha). After that's all done what would be the best steps to put a nice sharp edge on it? I have a belt grinder, but I can't imagine that a person would want to use that for the final edge, right?...

so how do i take off the remaining steel after HT and finalize to a nice edge?

Thanks ahead of time for your help everyone!!

Also, thanks to all of wise knife making sages on this forum...i've been frequenting this site nearly daily for various questions. This is such a treasure trove of knowledge, it's great!
 
I'm no knife maker, only done one, but from all my reading most do a secondary bevel at your desired angle depending on the knifes purpose.

After that, you have options on sharpening and polishing your edge. Stones, sandpaper, lapping films.
 
If done under power it is very important you keep the edge cool. If I'm doing it under power I do it wet and I run the belt grinder slow (1000 SFM) and use a sharp stiff backed 120 grit silicon carbide belt (these cut cool with low pressure) with the platen angled back at the angle I want it (frequently 13 degrees) and I hold the blade vertical and I grind the edge in (edge trailing, not edge first), taking care to keep the edge centered. Once it is down to a rudimentary edge I then sharpen it as I would sharpen any knife.

D2 abrades slowly and gets hot. Take care not to lose your temper.
 
I've learned to sharpen free hand on a stone, and I've also had a guided system like the edge pro. However, once I discovered paper wheels, I never went back.

You use them on a bench grinder, and they work excellent. From where you are now, you could have a polished, shaving sharp edge in about 3 mins.

You can get the whole setup for about $25.
 
I use diafolds from DMT
I start off with a 120gritt (made for ski´s/snowboards) then black-blue-red-green-strop

a 3:1 triangle gives you a 20° angle, a 4:1 triangle a 15°angle
 
I almost only use beltgrinders. What do you have? What belts do you have?

I sharpen professionally, and have nearly every contrivance known to man.

I started out very young on stones. Then I got really good water stones. Then I got an Edge Pro and collected all the good water stones and hones for that. It works superbly if you have the time.

I just did an event where I got to sharpen about 500 knives in a week. All I used was 3 1x42 Kalamazoos, with aftermarket platens. You can use whatever grinder you have, but you do have to use different belts. That's why I use 3 grinders. I use a 3-5 grit progression.

On a blade with .030 thick edge, you can start out with anything from a 40 grit belt to a 120 grit belt. The 40 grit just gets the majority of the work done in a flash, once you have the experience. It sounds like you could start with 80 grit or so. You have a lot of steel to remove to get the bevels to meet.

It's best to practice on cheap knives to get a feel for the game. It doesn't take a lot of practice, just some to figure out how you have to move the knife across the belt, and how to keep your tip pointy.

Once you get your bevels consistent and even on both sides, and you can feel a burr along the entire edge, go to a finer belt. If you start on 80, you can go to 240-320 grit. You only need to make a couple of consistent passes per side. I start on the platen, and then move just above the platen after the bevel is formed. It's a little more forgiving.

You can actually get a pretty sharp edge with that 2 step process, but I would recommend at least one more.

Depending on what size your grinder is, you'll want to finish with a fine structured ceramic or a leather belt with compound.

Most factories like Benchmade and Spyderco sharpen this way for a reason; it's fast and effective. Depending on your belts and skill level, you can probably do better than the factory with a little practice.

There are tons of youtube videos to watch to help you get started. If you have questions, just shoot me a line and I'll be happy to help.

Belt grinders are easily capable of stunning edges, and they are infinitely safer, more versatile and accurate than any wheels. For knife makers with belt grinders, it's a no-brainer.
 
The info given is all good on sharpening. However, you will have a hard time getting that knife sharp with the edge at a dimes thickness ( .045")

You want the edge on D-2 to be much thinner than a dime at HT. About .015" to .020: is more than thick enough. You will find that the sanding on D-2 after HT will be very slow, and removing fifteen to twenty thousandths of an inch of very hard, very tough, steel will be a real chore. You are shooting for an edge before sharpening on D-2 of about .005 to .010 ( depending on how the knife will be used ).
Once the bevels are sanded to the desired grit and the edge is at .005" to .010" ( almost sharp), put a small secondary bevel on at about 15 degrees per side. Sharpen it on a medium to fine stone. Strop the sharpened edge a few strokes on a leather strop with some rouge on it and the knife should shave hair.
 
Using a Bubble Jig is the fastest and most accurate way to develop the edge on a new blade. As Stacy said take it to .015 then set the edge on the belt grinder. For a normal blade its 2 passes per side at each grit. Feel the wire edge develop as you work the edge. It should feel equal and even from tip to plunge. I use a progression of 120 220 400 600 and strop. With a Bubble Jig this can be accomplished in about ten minutes.

Good luck, Fred
 
Fred's Bubble Jig is an excellent way to control the sharpening angle. My only caveat is that if you only have a single speed grinder, then that speed is almost always fast. Unless you have years of experience ( and even then I would not do it) sharpening the edge on a fast grinder is a sure fire way to soften the edge. If you have a VS grinder, us fresh belts and dead slow speed....or use a bench stone set.
 
Thanks, Grizz! That's great information to get me started. I like the idea of being able to to utilize my grinder as much as possible, so i don't need to buy too many more gadgets and whatnot (my wife can tell you how much I'd like to though!).

Do you happen to have recommendation on leather or ceramic belts? I have a 2X72 pheer grinder I picked up off ebay.

And with the leather belt I'm going use it like a strop and have it draw across the edge last, rather than edge first? Is that the same with the ceramic?
 
Thank you sir! That is really good to know..I was a little worried about how difficult it would be to finish off the edge after heat treating, as I'd heard that it gets pretty hard and tough to abrade. So it's good to know i can take more off.

After heat treat I'm just concentrating on grinding the edge, right? and not the rest of the bevel (aside from putting a polish on it)? Or if i'm grinding the bevel as well, what grit belt would you recommend starting out with?

Is there any reason to worry about warping with it that much thinner?
 
Thank you sir! That is really good to know..I was a little worried about how difficult it would be to finish off the edge after heat treating, as I'd heard that it gets pretty hard and tough to abrade. So it's good to know i can take more off.

After heat treat I'm just concentrating on grinding the edge, right? and not the rest of the bevel (aside from putting a polish on it)? Or if i'm grinding the bevel as well, what grit belt would you recommend starting out with?

Is there any reason to worry about warping with it that much thinner?
 
egally08 said:
I've learned to sharpen free hand on a stone, and I've also had a guided system like the edge pro. However, once I discovered paper wheels, I never went back.

You use them on a bench grinder, and they work excellent. From where you are now, you could have a polished, shaving sharp edge in about 3 mins.

You can get the whole setup for about $25.
Click to expand...

This is something i have not heard of before. I am going ot have to look into. I like the price point, that's for sure! thank you for the recommendation!
 
Sand and finish the entire bevels before sharpening. In the proper methodology, the whole knife should be done - Blade polished, handle done, sheath made, etc. - before the edge is sharpened. The only thing done after sharpening is to give it a coat of oil or Renaissance wax.....and to go cut something with it.
 
bladsmth said:
Sand and finish the entire bevels before sharpening. In the proper methodology, the whole knife should be done - Blade polished, handle done, sheath made, etc. - before the edge is sharpened. The only thing done after sharpening is to give it a coat of oil or Renaissance wax.....and to go cut something with it.
Click to expand...

Perfect! Thank you!
 
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