What grit sandpaper?

E

edcrefiner

Joined
Aug 26, 2010
Messages
270
Hi,

After searching I have found many people suggesting very different grits of sandpaper ranging from 600-4000 grit for sharpening. I have heard that 600 grit can get a blade shaving sharp but on the contrary I also read that you need at least 4000 grit to make things decently sharp.

Right now my knives are capable of cutting through paper decently but not super easily. Currently I am using a cheap stone that can make knives decently sharp. However, I am looking for the sandpaper that can take my knives to the next level.
 
Everyone sharpens a bit differently and has different expectations of the results, so you are going to find some variance on opinions.

Speaking very generally, you should be able to acheive a very sharp edge on 600-800 grit paper, after that you are polishing the edge more than actually creating the edge.

Personally, depending on how the dull the knife is, I usually start around 180-220, go to 400, 600, 1200, then strop on leather with black compound, then leather with green compound.

I acheive shaving sharp with this method.

Others may have a slightly different method, with similar results. The correct method is the one that works for you.

Sandpaper is inexpensive, don't be afraid of a bit of trial and error to find your sweet spot.

Kevin

PS, if the edge isn't already convex, I sometimes go as low as 60-80 grit to establish the edge profile before sharpening. Then start working up 120, 220, 400, etc. etc.
 
Last edited:
Knife sharpening is 95% the skill of the user, and 5% the tools you are using.

A cheap stone is not going to do the job very well, but you CAN put an edge on a knife that way. Sandpaper works, and most people who sharpen this way end up using the paper on a mousepad or other material that has some "rebound" to it, and this will convex the edge of a knife. There are many pros and cons to doing that, but I have convexed a few of my blades.

Most sharpening mediums that one can use, be it Arkansas Stones, Japanese water stones, Belt Sanders, Sandpaper, diamond stones, etc, will have different grits going from coarse to fine. Coarser sharpening mediums remove the most material the fastest, but finer sharpening mediums can really put a fine edge on your blade once you've got the primary edge formed and have the proper edge geometry.

My recommendation would be to seek out some sharpening instruction first, and then figure out what methods you want to try. This way, you can research a method that seems like it will work best for you, purchase the tools, and practice practice PRACTICE! It really does take a lot of repetition to get it right, but keep in mind the first thing that I said... It's more about your skill, and less about the tools you use.

There are many guys on here that use many different methods of sharpening, and with every method there are people who can put ridiculously sharp edges on knives.

And if you are curious, the first knife sharpening instruction I sought was by Murray Carter. I use his methods most of the time, and for that I use a coarse (1000 grit) and a fine (8000 grit) japanese water stone, and I can put hair popping, hair whittling, scary sharp edges on my knives. I recently started using a leather strop to finish the blades once the edge is pretty sure, and it just takes it to one more level of sharpness. But I can also put a shaving sharp edge on a knife using different grits of sandpaper and a mouse pad.

A lot of words, but I hope it helps! Good luck!
 
Thanks guys for the detailed replies. I really learned a lot. Do you guys think it is possible to not convex the edge? For example, I was thinking of taping the sandpaper to my stone and sharpening normally.
 
Yes, that will work to keep the edge a V, the mousepad that has give is what gives the convex edge. When I use sand paper I usually start at 600, then 800, 1000, then 2000 (which you should be able to find all at a auto store like Autozone) When I use my belt grinder ($36 from Harbor Freight) If I'm reprofiling I start at 600, then 800, 1000, then a leather belt with stropping compound. This gets my edge mirror polish shaving sharp and takes more time to change the belts around than the actual sharpening, except for maybe a thicker edged ZDP-189 blade.
 
The grits mentioned above are about right and will work very well. I'd suggest getting silicon carbide paper (wet automotive grade) and use edge trailing strokes. You can find much finer grits of you feel the need, but usually 2000 will be plenty for the final application. Remember to let the paper do the work, take your time and use light strokes.
 
I use 320, 1000, 1500, 2000 grit sandpaper, in that order, when sharpening with sandpaper. Then I strop.

As for taping sandpaper to stones, yes, I'd say that's possible. What I've heard of a lot of guys doing for sharpening chisels and plane irons is taping or gluing a piece of wet-or-dry sandpaper to a piece of glass and using that to sharpen their tools. Apparently it works exceedingly well, and while you have to replace the sandpaper every once and a while, the glass will never 'cup' or wear out.
 
From my limited experience, I have found that the actual values of the grits chosen doesn't matter so much as a few general rules do:

1) Start with whatever grit cuts the best on the particular blade you are sharpening based on it's steel and it's degree of damage/nicks/sharpness
2) Step to finer grits as you progress to remove the scratches left by the previous grit and to keep taking off the burr that you create
3) End with the grit that gives you the sharpness and polish that suits you and that particular blade

That being said I personally have started with as rocky as 60 grit to remove some damage and nicks from an old meat cleaver and I've finished as silky 1200 to give the polish I wanted on a nicer folder. The detail that makes this method work so well (IMHO) is STEPPING through the grits not exactly where you start and stop.
 
For my convex Bark Rivers, I make my sharpening strops like this: a piece of 3/4" hardwood or MDF, 11" long by about 3-1/2" wide. Glue a nice piece of 8oz leather to both sides. Tape your sandpaper to the leather.

I hold the "strop" in my left hand and can turn and adjust it slightly as I'm stropping the knife edge.

The first pic is one side of the "stropping" boards, the second pic is the back side.
convex-01.jpg

convex-02.jpg
 
All good suggestions :thumbup:.
I would make sure you get 220 for really dull stuff and for reprofiling from V to convex.
The highest you'll realistically need is 2000 grit, beyond that the difference between say 2000 and 3000 is so minimal it's practically unnoticeable. The high grits polish more than they sharpen.
 
Hi guys sorry for not replying sooner because I was busy attempting to sharpen my knives. And as you guys have mentioned, sandpaper polishes more than it sharpens. None of my knives that I tried to sharpen with sandpaper actually got much sharper, only shinier. That said, I got my spyderco with 8cr13mov pretty sharp (with a stone, finished with some 2000 grit) while my AUS 8 SOG flash 1 is still pathetically dull. No matter what I can't get that thing sharp. Tried using a stone, sandpaper, bottom of a mug, ect still dull.... been at it for a few hours and it is still only sharp enough to cut paper "with the grain" relatively easily but when I cut "against the grain" it only rips the paper.

Does this have something to do with the grind of the blade? For example one side's grind is 3x taller than the other side. It came like that out of the box.
 
Don't move to finer grits until the edge is sharp. Finer paper/stones removes less metal, reducing the scratch pattern and smoothing the edge. Wherever you start, get the knife to cleanly slice paper or shave the hair from your arms before moving on. The next steps in the sharpening process improve an already decent edge, not fix a bad one.
 
Stretch,

Nice job making the boards. I am still in the gathering stage for materials to make my own. When you sharpen, do you go with the edge (as if trying to shave it off) or against the edge (like spreading butter)? I'm quite a novice at this and really could use a hand. Also, I'm not sure I am understanding the meaning of "convex". Is there a site, or a thread on this site, that explains all the grinds, bevels and nomenclature used in the knife world?
I didn't mean to hijack this thread op, I'm in the same boat as you and seem to be getting the same results.
 
Thanks for the link. interesting my sog flash 1 appears to be a scandi grind. Except one side is like 3x more ground than the other.
 
You must log in or register to reply here.
Back
Top