Convex Sharpening

Well. I failed at my first attempt at convex sharpening. I used a mouse pad,220 and 400 grit sandpaper, and follwed the directions. The knife a small Case paring knife in carbon steel. It was already sharp enough to shave arm hair and slice newsprint , so I figured it would not be to much work. After about 30 minutes of trying I ended up with a knife that would not shave arm hair or slice newsprint.
 
Upon further review of the video he said to use 2000 grit not 200.:o, Oh well, you live you learn.
 
I start with 600 then proceed to 1000, 2000, 3000 1nd 4000. If I really want a bright shinny edge, I go with 6000 and even 10000. The 6000 and 10000 are mostly cosmetic, but it looks cool:cool:.
 
great series of videos! i would say he deserves a BRKT for all the work he put into that, and the content.

dipbait, you can go from 200 grit to a strop and get a wicked sharp edge. don't get discouraged, keep trying!
 
Most automotive stores will carry upwards of 2000 grit wet/dry. Beyond that I'd suggest looking at a hobby store, particularly one that has a lapidary section as they'll almost certainly have higher grits.


Gautier
 
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Gautier, I am over in PHX. I have tried AutoZone, and the highest at the time I could find was 1000. Would an autobody supply shop carry higher? As far as craft stores, would Michaels be one such source?
 
I know the AutoZone out here carries up to 2000. A body shop may or may not carry higher grits, and as far as Michaels I'm not sure. To be honest, I don't think I've ever been inside a Michaels. Like I said though, most jewelry supply or lapidary supply shops should carry it and I know there's at least a few type shops in Phoenix, after all this is rock country :p.
Irons I believe is one of the jewelers and Lonnies down there has some lapidary supplies, grinders and what not, worth a look I'd say. Can check Lonnies website below and see if you come up with something before driving down there.

Edited to add:
Never mind, found some for ya

http://www.lonniesinc.com/Products/Tools/Abrasives/3m_wet_or_dry_polishing_paper.htm


Gautier
 
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dipbait said:
Well. I failed at my first attempt at convex sharpening. I used a mouse pad,220 and 400 grit sandpaper, and follwed the directions. The knife a small Case paring knife in carbon steel. It was already sharp enough to shave arm hair and slice newsprint , so I figured it would not be to much work. After about 30 minutes of trying I ended up with a knife that would not shave arm hair or slice newsprint.
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Dipbait, I can't tell you how many times I kept failing at this. It was really frustrating as I would end up inevitably dulling my knife. I was always starting with v-grinds though.

Just like when you are starting on a dull v-grind you have to carry through your sharpening right to the edge. If you are converting your V-grind to a convex, then you want to spend a lot of time on the 220 grit until you have formed the rough convex edge. Then from there proceed up the grids. I found that it was okay to do about 10 passes one side at a time at this course grid. Keep using the sharpie technique until both sides have been shaped to the edge itself.

Don't lift the knife spine too high and don't press too hard. Once you've shaped the edge at 220, go to 400. Now proceed with fewer strokes/side before flipping over and doing the next side. Look at the bevel under a lamp and proceed until you've polished all the 220 grit scratches to a 400 polish. Proceed to the 800. You will start to feel the edge getting sharper and grabbier with each grit change.

A final note. I don't find the (my) convex edges shave hair with the same ease as a V-grind but they perform better on other tests like push cutting paper and news print. I found that 10 light strokes on the white rods of the sharpmaker at 40 degrees puts a nice little micro-bevel that gets the knife both hair shaving and push cutting. I find that easier than the strop, but others get better results with the strop.
 
siguy said:
great series of videos! i would say he deserves a BRKT for all the work he put into that, and the content.

dipbait, you can go from 200 grit to a strop and get a wicked sharp edge. don't get discouraged, keep trying!
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Simon - are there any tips you would add to this volume of knowledge?

I know you are highly praised for your sharpening.

TF
 
I use a altoids tin with soft rubber glued to the top. I cut wet/dry paper up to 2500 grt in a rectangular shape with cutouts on the sides at each end. This lets me close the lid on the paper while sharpening. I store the papers inside the tin as well. I switched from leather to soft rubber because i wanted a more curved tougher edge on my knives and hatchets.
 
Simon - are there any tips you would add to this volume of knowledge?
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there isn't really much that i could add to that, except i might stress that a convex edge can be as thin or thick (as flat or curved) as the user sees fit. he did touch on that in the video though, he just didn't stress it.

the biggest misunderstanding that i see about convex edges is that they are all ground like a splitting axe...but i have everything from disposable razor blades to axes with a convex grind, it really still depends on the angle and finish grit to determine cutting ability (just like a flat edge).
 
Thanks Derrick for putting these video's up! They have helped alot!!

I use the strop and black and green compund that you sell at your site. It works great!!!

I haven't tried tip to heal sharpening yet, but I can see that it would make sure the tip is done.
 
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Most Wally world stores have up to 2000 grit. I got 3000 grit on Ebay and I really like the 3000. I got 4000 from Pops's Knife supply and 6000 and 10000 at Who's Hobby Shop, Rapid City SD. Lee Valley tools also has it all.
 
Yep, very good videos!
NEVER delete them from your website!

Thanks for the tip about Who's Hobby Shop, I haven't tried there.
I have a few sheets of 2K grit right now, but at least I know where to go when I need more.
 
okbohn said:
He is Tradja on Knifeforums--I don't know if he has an ID over here. A great guy and obviously an excellent teacher.
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I think he goes by the same name here. Hell of a good guy and spends some serious time on the trail - hence not being on the forums so much.
 
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