Convex Bevel sharpening

[Shaun Mahood]

I think the biggest thing for me was that I didn't know that a convex bevel was "allowed", and it never crossed my mind to try it. I had pretty much resigned myself to either having to buy a grinder, using my jig, or spending a whole lot of time using less sharp chisels as I learned to freehand them. I spent a ton of time reading on the internet, read all the sharpening books I could find, and watched all the videos I could find as well. This is the first sharpening method that has done everything I want, and it does it quickly and gets things very sharp, so I'm happy. I'm glad you guys are happy with your methods too!

I'm not sure about the effective difference between secondary bevels and the convex bevel. For me though, sharpening in a convex bevel gives me a very easily repeatable action that I couldn't get the hang of with a secondary bevel. I would always second guess myself on the angles, and found moving back and forth keeping on the same plane without a hollow grind quite difficult.

I also think there is something to the stropping involved, since by putting pressure on the center of the convex bevel the leather seems to compress in the shape of the bevel and polish it all at the same time. Kind of pointless to have the back half super highly polished, but I haven't had the same problems dubbing the edge over as I used to.

Anyways, I doubt any of it really matters much when the blade hits the wood. Main difference seems to be whether you use a grinder or not.

[David Weaver]

Yeah, there aren't really any rules to the bevel of a chisel, especially when the entire thing is the same steel.

If it works for you, then you use it.

I've gotten a lot of old chisels that were sharpened with a convex bevel like that, some more gradual than others. I've also gotten old chisels that were flat, and a lot that were dull, so it's hard to tell who sharpened them.

For anyone who has used a sandstone wheel grinder like the old ones (george?), presumably you will get a rounded bevel with those, too? It's not like they have a tool holder on them, at least not the ones I saw.

[Jack Curtis]

I have a couple of old Japanese chisels that could be called convex bevelled, use them for hard duty such as chopping mouth mortises in hard wood. Also a pile of old mortising chisels from the UK, the big ones with huge oval boxwood handles, for the same reason. In both cases they're made/sharpened this way so the edge is backed up by a mass of metal.

[Salem Ganzhorn]

Jim,
Thanks for posting this. I recently picked up some chisels from another member on this forum and one of them is a long 1/8th buck bro's. I have always had difficulty sharpening narrow chisels.


Untitled by eyekode, on Flickr

I tried my normal routine but my grinding skills are just not good enough for the narrow chisels. I remembered this thread and thought I would try out the convex method described in the video you linked.


Untitled by eyekode, on Flickr

My initial impression is very positive. I have been a dedicated hollow grind kind of guy for quite some time. But maybe that has changed?
Thanks again!
Salem

[Charlie Stanford]

Paul Sellers on how he sharpens....

http://www.youtube.com/watch?v=a6ykV...layer_embedded

Anyone sharpen this way...?

Jim

Not at present. Seems like that would make a chisel back up in a mallet driven cut much more than a flat ground or hollow ground chisel. You can certainly make allowances for it. Seems like the advantage would be rarely having to visit the grinder.

[Warren Street]

I have moved from a jig to Mr. Sellers' method and found that edge retention is much better on my cheap Narex chisels. They would fold/roll and chip very easily at 30 degrees and was very frustrated with them. I thought it might have been the chisels but after using the Paul Sellers method I've found that the edge stays sharp much longer and there's no chipping or rolling. Very happy as it's very fast and works very well.

[David Weaver]

I don't know if I said it in this thread, probably not, but most people that use the method are going to end up steeper than 30 degrees, and any chipping from abuse should all but disappear. You may not always want such a steep bevel, but it's not like all of us can't figure that out for ourselves individually. If it works, do it.

[george wilson]

I watched some oif the "bird chirp" video,but could not understand a word that was mumbled!!

[Chris Griggs]

Yep, sharpen a chisel at 35 degrees and it won't roll either, unless its it inordinately soft. When I'm using my bench chisels for heavier than typical work I'll just lift the edge off the hollow grind a few degrees and it gives me the same effect. The secondary bevel is so small that when I want it back to a more standard angle I can often just hone it out on my 800 grit stone. Worst case scenario I spend a minute at the grinder, to remove it.

[David Weaver]

That would seem a better method. A lot less sensitive to steel hardness or what kind of stone you're using.

[bob blakeborough]

I have been pondering this whole convex bevel idea for a while now. The last couple days off I have had I have spent re-establishing the primary bevel by hand (no grinder in my shop) at 30 degrees on all of my chisels and plane irons using my MKII Veritas sharpening jig (I am a fan of this jig BTW). Now I am looking at either continuing how I have always sharpened (using a jig and micro-bevels) or taking this opportunity to start mastering (I use that term loosely!) freehand sharpening. I am pretty determined to go the freehand route except for when I need to re-establish a bevel for any reason.

I have my beater Narex chisels that I might practice this convex bevel method with before ever turning my BS chisels to stone, but I know most people who use this method use diamond plates or oil stones then finish with the strop. I have diamond plates up to 1200 and water stones up to 8000 and the strop. Will the convex method kill my water stones as they are not as tough as the primary options?

[Chris Griggs]

I watched some oif the "bird chirp" video,but could not understand a word that was mumbled!!

LOL. I love that video!

[Adam Lewis]

i have been doing this for a number of years with my pocket knives. only i just use a strop with some sand paper on it if i have to regrind a "bevel". it is something i learned form the guys at bark river knives. they grind all of their knives by hand with a convex bevel. i have found out that it is easier to maintain the edge with quick touch-ups than to get out all the equipment and start honing a new bevel. also the knives tend not to dull as fast, as there is more meat behind the edge to keep the steel from rolling or to keep the carbides from breaking off. sure the angle may not be perfectly 25 or 30 degrees, but it is close enough that the wood sure doesn't care. i tend to think of the jigs as something more modern anyway. but to each their own. if it works for you, then who is to argue that one way is better than another.
this is just my humble opinion....i could be wrong......

adam

[David Weaver]

I have been pondering this whole convex bevel idea for a while now. The last couple days off I have had I have spent re-establishing the primary bevel by hand (no grinder in my shop) at 30 degrees on all of my chisels and plane irons using my MKII Veritas sharpening jig (I am a fan of this jig BTW). Now I am looking at either continuing how I have always sharpened (using a jig and micro-bevels) or taking this opportunity to start mastering (I use that term loosely!) freehand sharpening. I am pretty determined to go the freehand route except for when I need to re-establish a bevel for any reason.

I have my beater Narex chisels that I might practice this convex bevel method with before ever turning my BS chisels to stone, but I know most people who use this method use diamond plates or oil stones then finish with the strop. I have diamond plates up to 1200 and water stones up to 8000 and the strop. Will the convex method kill my water stones as they are not as tough as the primary options?

It will if you push a chisel in hard enough to gouge them. You can quickly get used to adding pressure only on the pull, though, and let the chisel just ride the stone back on the push without pushing it into the surface. It's no harder in the end, and a fresh waterstone is probably faster on the pull than a worn diamond stone is on the push and pull together.

Realistically, though, there is no need to do all of that crashing around with your finish stone. Find where your bevel is, lift the handle a degree or two and pull the chisel three or four strokes and work the back a little bit.

The whole reason I yammer on and on about a grinder and two stones is because you can literally come fresh off the grinder, use a medium stone three or four strokes right on the hollow as a reference and raise a wire edge. Go then to the finish stone, work the back for ten seconds and then lift the handle a tiny bit, just a couple of degrees, and just pull three or four strokes. The secondary bevel will be so small that it will take almost no work to raise a wire edge on the flats of the hollow again the next time, but the edge will be spectacular, and you won't need to strop if your final stone is an 8k strop. If there's dirt or particles on your strop, it'll actually worsen the edge.

It's a 30 second process with a chisel, add a minute if you need to grind each 3 or 4 times you refresh an edge from dull.

[Sam Stephens]

To call it "convex" suggests something more exaggerated, akin to the opposite of the concave bevel produced from a hollow grind when it practice paul sellers' "method" is what most free hand sharpeners do -register the bevel on the pull so that the edge just makes solid contact and a slight pressure to tilt down the back of the chisel/plane on the push to avoid ramming the edge into the stone. This of course is no more than the mechanics of the motion of pushing and pulling a chisel or plane iron across a stone. There should be less than 5 degree overall difference in the chisel angle.

if you stop at 1200, then yes strop, if you go to 8000 then the improvement is going to be negligible. however for touching up an edge during use, the strop is mighty handy.