mousepad sharpening help!

S

sizzler

Joined
Nov 14, 2005
Messages
276
soo, I checked as many threads as I could and maybe need some more help with this.

So I have this knife, thick blade, convex. Was never very sharp from the get-go and I tried all of the tricks and followed all of the videos. Been through 800 - 2000 grit on mousepad, open cell foam, minicell foam, cardboard, leather. Used the sharpie as well. Tried all different angles and pressures.

I have slightly knocked the shoulder off of the secondary bevel, but that's about it. I can't get the knife any sharper than paper tearing and hair scraping! Sometimes it stays sharp, and sometimes I screw it up and make it duller, but it will never get "sharp". This is getting really old after the fifth total hour at this. About ready to pay someone to do it as I have no access to power tools.

Any suggestions? Please?

Thanks
 
Your changing it to a convex bevel?

If so then you probably need to start at 220 grit or lower.
 
Not sure about whether the bevel was convex or not. I should ask. Might try the lower grit but didn't want to permanently screw anything up or have to send it back for sharpening. I really don't want to be one of those pain in the ass customers.

I assumed it was a convex bevel because it didn't seem to make sense having a v grind on a convex blade, but, I'm new to the convex thing so I could be wrong.

Thanks for the help!
 
There should be no need to go to even 800. But if you start there fine, just don't over sharpen or you'll have to 'reprofile' and that's a bit of a pain.

One of the biggest problems i see is people getting the 'angle' right. First off - stick with leather for now. Not all mouse or cardboard pads are the same, and some are too soft or hard.

Now - here's how to get the angle right.

First off - ZERO pressure. I mean NONE. Not a THING more than the weight of the blade. That is key.

Second - lay the knife almost flat. Begin to drag it along the medium, and raise the spine a little as you go. (remember - no pressure.).

You will suddenly feel it 'bite'. The friction and even the sound will change in an instant.

THAT is your angle. Right where that change happens, that's where you want to be (possibly backed off a hair.) It's not necessary to be 'precise' every time, but you want to stay very close to that.

Now - using that angle do your stropping. It's ok to focus on the flat of the blade rather than the tip at first - it'll be easiest to know if you got it 'right', and you can do the tip next.

go slow, and every now and then re-check the angle using the same trick. NO PRESSURE.

That should result in a sharp knife pretty darn fast. Even starting with something like 1000 or 1500.

If you've kind of 'over sharpened', then the only thing you can do is go down to a low grit and start all over, doing one side only till you get a burr then flipping and doing the same with the other side. IN that case, use the same trick but back it off just a tiny bit and to till you get a burr (very little, not much)

But it wouldn't shock me if you just get the angle right and focus on NO PRESSURE then you'll likely be surprised. Unless the knife is so dull it couldn't cut butter, i usually start with 1500 grit and finish with a .5 micron film, and even before the film it's 'sharp'.

Give that a try and if it's still bugging you, i'll see what i can do to help from there :)
 
If its a convex blade then your probably doing it right, who is the maker?
 
hmm, okay, sounds pretty much like what I was doing but I will do some more work with the leather backing. Obviously, something is wrong and most likely it is my technique or method. It does get "sharp" sort of. I can sort of cut/tear paper and scrape off an arm hair or two. It will definitely cut steak and food, but it seems to stall out at that point and won't get any sharper.

I'll give what you suggested a go.


Thanks!
 
i'm having a similar problem! ....im just not getting the knives particularly sharp....

how long should it take to take a knife from a straight bevel to a convex edge?

just cant figure out what im doing wrong....

I know i need to get myself a leather strop though....
 
Try with lower grit (< 220), work the edge lonmger with the lower grit to thin the edge.
 
I think the lower grit is what it might need. If I had any hair I would be pulling it out by now! Tried everything else BUT the lower grit and it feels sharp, looks sharp, won't cut paper, won't shave a hair. Thought it might be a microscopic burr, but I tried to remove it with some rubber, cardboard, and wood to no effect.

Anyone know of any "for-hire" knife sharpeners with a good reputation?


Thanks
 
What knife is it?

LIGHT pressure, just the weight of the knife, maybe less. Start with a lower grit paper, see if it catches on your fingernail. Too much pressure will dull the knife, keep your angle steady as well.
 
I've have good experiences with Simon. He's pretty good with convex grinds, but sometimes on larger blades his bevels get a little funky. He very inexpensive as well, He used to (he may still) offer a free sharpening for the first box you send it. Not just the first knife, but the first BOX of knives you send him. http://www.freewebs.com/sfaknives/
 
You are using the wrong grit. You need to start with much lower grit like 220 or maybe 320 to remove steel.

800-2000 is for polishing. It is no surprise that you have only managed to round-off the secondary bevel. You are wasting your money with these grits, save it for the final polish.

Use the lower grits (220-320) to remove steel faster before you put a final edge on it.

You can also buy a diamond hone for the initial edge shaping before going to paper. (spend more for a better one, it'll work better and last longer)
 
In 99 out of 100 cases, if you're not getting a good edge, you're applying too much pressure.

I like 1500 grit wet/dry paper (kept wet, and washed often) on a hard leather backing.

I also like to sharpen in a stropping motion, one side, then the other to prevent forming a burr.

Of course, if you do much convexing, a belt sander is almost a necessity.
 
It's a six inch fixed in o-1 steel. Don't think it is the pressure. I have been really careful about that to the point where the knife is just barely skimming the paper most of the time.

Was holding off of the coarser grit because the knife should be sharp already and I didn't want to screw things up. So, off to the store for some more paper and maybe a hone.
 
Start with 400 grit, and use a fair amount of pressure until you get the scratch pattern all the way to the edge. Now 800,1200,2000 useing a fair amount of pressure, removing the previous scratch patterns all the way to the edge. Now useing light pressure, adjust the angle of the blade so the edge is being worked on your strop.This is where the light touch pays off. So start with pressure, finish light.
 
question, for convex sharpening, do you push into the edge (like with a standard v angle) or do you pull away from the edge (like with stropping)?
 
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