Convex bevel troubles

[Steven Mikes]

I was attempting to follow Paul Seller's sharpening method which results in a convex bevel on the plane blade. I think what ended up happening in my case is that with repeated sharpening I inadvertently increased the curvature of the convex a little bit each time. It got to a point where I could reach the edge of the blade anymore without increasing the angle excessively. Now I'm trying to grid it back flat using a honing guide and it's taking forever :(:(. Is there a trick to avoid this?

[James Pallas]

Hello Steven, I learned to sharpen in this fashion. I have to say I no longer do it. It works fine. There is some muscle memory involved. You must keep it in mind to never go past your angle on the high side. Your brain will try to tell you to reach up to get to that edge, don't do it. On the low side it won't make much difference. My guess is your mind is tricking you and you are getting the typical result. The only way to fix it is to remove steel. Maybe after that chore it will help you to remember. I hollow grind and side sharpen nowadays.
Jim

[Robert Hazelwood]

You could make yourself a reference block. Take a 3/4" thick section of scrap, about 3" long and 2" wide or so. Take a protractor set to your desired edge angle, say 30 degrees, and mark the angle on a face, starting from the middle of the reference edge and going up towards one end. Cut to the line, removing the triangle-shaped offcut, pare/plane to the line if necessary. Now you can set the reference edge on top of your stone, and one end of the block will be angled up from the stone at 30 degrees. Hold the chisel up to that end to see and feel what a 30 degree angle is. Now you can remove the block and sharpen. You can repeat this as often as you need to during the sharpening process until you are confident about the angle.

[Andrew Pitonyak]

Send it to me, I will send it back sharp with a concave bevel so that is is easier to freehand. :D

I assume that you are free handing, right? Indeed you are correct that this is common when you free hand. I have no real advice there. I almost always use something mechanical to hold it in place unless I put a concave bevel on it at which point it is easy to free hand. I think that Rob Cosman sells something with magnets that holds the blade at a specific angle, which might help improving your free hand. I vaguely remember hearing, however, that this is common to see on older blades (convex edge).

[Bob Leistner]

I only run into that situation when I'm too lazy to go back to a very coarse grit and work back the bevel at least every other sharpening. If you habitually go back to 300-320 grit you shouldn't have as much trouble.

[Patrick Chase]

I only run into that situation when I'm too lazy to go back to a very coarse grit and work back the bevel at least every other sharpening. If you habitually go back to 300-320 grit you shouldn't have as much trouble.

Or just get a flat-disc sharpener (WorkSharp, Veritas, or one of the knockoffs) and use that to flatten the bevel every so often.

[Warren Mickley]

I think you are following horrible advice. It is as if Sellers had trouble keeping a flat bevel and so pretended it did not matter. If you look at this picture of Sellers' chisels, you can see he is having the same problem as you; he is sharpening at about 45 degrees. If you watch his videos he says it is about 30 degrees, but it quite obviously is nearer to 45. You will have the most control and consistency if you use a flat bevel.
369908

[Bob Leistner]

Yikes, I had no idea that is Mr Sellers idea of convex. Mine end up a bit convex but I don't think I would try to end up like his. I do occasionally put an edge to a gage, and I'm usually right around 30+/- a couple.

[bridger berdel]

a little convex is unlikely to cause problems. the tool will tell you when the edge is too steep. I am not shy about using the bench grinder to keep the heel of my chisels from getting too fat and the bevels from being too rounded.

[ken hatch]

a little convex is unlikely to cause problems. the tool will tell you when the edge is too steep. I am not shy about using the bench grinder to keep the heel of my chisels from getting too fat and the bevels from being too rounded.

Bridger,

What ever works, amirite :). Like you I'm not afraid of a little convexity, the tool will tell you when it is time to grind.

ken

[Patrick Chase]

I think you are following horrible advice. It is as if Sellers had trouble keeping a flat bevel and so pretended it did not matter.

More like he had trouble keeping a flat bevel and so turned it into an exaggerated fetish.

Seriously, how do you "ride the bevel" with dramatic curvature like that?

[Stanley Covington]

I think you are following horrible advice. It is as if Sellers had trouble keeping a flat bevel and so pretended it did not matter. If you look at this picture of Sellers' chisels, you can see he is having the same problem as you; he is sharpening at about 45 degrees. If you watch his videos he says it is about 30 degrees, but it quite obviously is nearer to 45. You will have the most control and consistency if you use a flat bevel.
369908

Amen.

Mr Seller's sharpening technique works for him, but it is not something to emulate. You can do better.

A rounded bevel has its uses, especially in the case of carving tools. But as Warren says, the flatter the better. Also, it is much quicker to resharpen a flat bevel than a rounded one because it is easier to find and then focus one's efforts on the extreme edge, which is what really matters. The time, effort, and stone mud spent making a rounded bevel is waste.

[Doug Hepler]

Steven,

Without knowing your setup and your comfort zone, it's hard to know what to recommend. If I had your problem (given my setup) I would hollow grind your convex bevels on a high speed dry grinder using a 60 grit white (ALO2) wheel. Then you can take the hollow ground edge to flat abrasives (stones or sandpaper). The hollow grind makes hand honing easy except for the narrowest chisels, when I use a jig (Veritas MKII). I used to use the jig more often but my skill in feeling the bevel has improved.

There was a day that I would never touch a good chisel or plane iron to a dry high speed grinder, but that was long ago when I had mostly carbon steel tools and a lot more patience. I learned HS grinding when I took up turning and was soon able to grind without overheating the edge. (dress the wheel, very light pressure, keep moving, quench often) I have re-shaped my share of edges by hand on a flat stone but that is just too tedious for me today. Modern HSS is fairly forgiving of overheating and too hard to shape by hand (IMO). If you have a HS grinder, go get an inexpensive chisel from the hardware store and practice grinding and honing it until you get some confidence.

I cannot understand/agree with Paul Sellers ideas on sharpening except that you should hone very lightly and very often. A hollow ground edge facilitates hand honing. When you press down on the very edge, you can feel the bevel "click" into the angle you need. Honing freehand facilitates frequent light honing. Also, if you want to hone by hand, it is easier to do if you use "trailing edge" honing, the opposite of what we were taught. When you are down to the finer grits, you can call it stropping on a stone if you like. Even if it creates a wire edge, we knock it off when we flip the tool over at the end.

Doug

[Mike Henderson]

Or just get a flat-disc sharpener (WorkSharp, Veritas, or one of the knockoffs) and use that to flatten the bevel every so often.

Yep, grind a 25 degree primary bevel and then put a micro bevel on to the angle you want - 30 or so degrees. Quick and easy. Do the secondary bevel freehand on a 8000 stone.

Mike

[Todd Stock]

I love a nice, long slightly convex bevel...on a carving chisel. For everything else, flat or concave and about 5 degrees less than I want to hone. What was he thinking, beyond keeping the subscription bucks rolling in?

[James Pallas]

When I said I learned to sharpen that way. It was done on the job on the end of a saw horse on a combination carborundum stone with a little bit of 3 in 1 oil. You shot for a flat bevel but it usually ended up somewhat convex over time. I don't do that now because I don't have to. Paul Sellers can do as he pleases and teach as he pleases. We can say what we want but it's difficult to argue with results. He does in fact make some very nice things and people seem to get a lot from his teaching. YMMV
Jim

[David Myers]

I don't sharpen most tools freehand. I will only say that PS occasionally mentions he lowers the angle to cut back on the convexity then raises it again to get back to the edge.

I don't know how often or on what grits he does so.

And I agree with the comment above. He makes good projects, good videos with tools accessible to any handtool enthusiast. Feel free to adapt or discard his methods, just get your tools sharp.

[Prashun Patel]

While he doesn't say this, I believe his method works for some because the rocking makes it psychologically easier to hit the edge on the front part of the stroke.

I prefer to freehand only because I am lazy and it's quicker than setting up a honing guide. Hollow grind, flatgrind off the Worksharp, or convexly beveled after repeated freehand honings: with enough practice, you will learn to find the edge and recognize when you have it.

At the risk of hijacking, I have a question: I have lately identified that when I'm honing the edge properly, there is a distinct sound and feel. It drags almost imperceptibly more than when I'm on the bevel and not quite at the edge. It also sounds "scratchier". I can't explain why that is, and I suspect it's in my head. Does anyone else experience this?

[Derek Cohen]

The rounded bevel method is useful for the secondary bevel of mortice chisels, which is where I use it (and only there), since a guide does not work well here. To ensure that I do not go over 35 degrees, I keep a wooden guide on hand. This is angled at 35 degrees.

https://s19.postimg.org/wrddcrr77/813b297c-6daf-4708-baad-279e19ce4d58_zpshjiiywbe.jpg

Start at the low end and pull to the high angle ...

https://s19.postimg.org/hveu56nib/Honingmorticechisel1_zpsad015f6a.jpg

This is what one should end with ...

https://s19.postimg.org/540nyolg3/mortice-guide2_zpsmrald6b3.jpg

Regards from Perth

Derek

[Jim Koepke]

I don't know how often or on what grits he does so.

One of Mr. Sellers videos made me lose any credence in his 'teaching' abilities. It has him saying one only needs to hone their blades up to a 220 grit because that is where people stop sanding before they apply any finish.

There were other videos of his that also made me think he doesn't have much of value to help me.

As stated before, more than one of my posts has contained comments about how a convex bevel may be useable, but it is surpassed by almost all other methods.

One piece of literature suggests in the early days of Sheffield tool makers tools were hollow ground because the workmen at the time would refuse anything with a convex bevel.

Often the "quick and easy way" can lead to learning bad habits.

jtk

[Steven Mikes]

Thanks for the input everyone, looks like I will be avoiding free-hand sharpening for awhile (and just using the eclipse-style honing guide I already own). Unfortunately I don't currently own a bench grinder. Would one of the $40 6" grinders from the BORG be sufficient, with a 60-grit aluminum oxide wheel as suggested by Doug?

I did finally fix the bevel with the help of some courser sandpaper, finally back to a good edge that's cutting well again. Now I'll have to do the same to my other blades *sigh*

[Jim Koepke]

Thanks for the input everyone, looks like I will be avoiding free-hand sharpening for awhile (and just using the eclipse-style honing guide I already own). Unfortunately I don't currently own a bench grinder. Would one of the $40 6" grinders from the BORG be sufficient, with a 60-grit aluminum oxide wheel as suggested by Doug?

I did finally fix the bevel with the help of some courser sandpaper, finally back to a good edge that's cutting well again. Now I'll have to do the same to my other blades *sigh*

I have no idea how well the grinders from the Borg may be.

My "grinder" is actually a flat disk (Veritas) sharpening system. So far all of my tools with sharpening needs have been able to be worked on this setup. That includes knives, hatchets, axes, shovels, metal working tools, woodworking tools and the occasional piece of wood.

A regular grinder will produce a hollow grind which makes hand sharpening easier. A flat disk set up produces a flat bevel. Over time my chisel bevels may get out of true flat and then it is time to reestablish the bevel.

One advantage of the Veritas sharpening system is changing grits is quick and easy. With a regular grinder you may have two wheels and the changing of grits is likely to be forgone as it is a bit of work.

jtk

[Doug Hepler]

Steven,

I had the grinder for general work before I adopted the regimen I described earlier. So, my investment was actually just two new ALO2 wheels and two tool rests. AND i use it to sharpen turning chisels (which is a different thing). If you don't need a grinder for purposes other than sharpening hand tools, I recommend that you consider the Veritas flat disk system that Jim mentioned above.

If you want a grinder, Fine Woodworking did a review back in 2012 and recommended the Porter Cable PCB575BG. The basic grinders are all about the same, two abrasive wheels on a motor driven shaft. If it runs true it will be OK. The amenities are what differentiate one from the other -- shaft length (you may want to move up to CBN wheels some day), variable speed, work light, tool rest. If you plan to sharpen chisels I suggest that you also get a Veritas tool rest.

Doug

[Patrick Chase]

While he doesn't say this, I believe his method works for some because the rocking makes it psychologically easier to hit the edge on the front part of the stroke.

Yeah, but it's like a heroin addiction in that you have to keep rocking it more and more to ensure that you continue to hit the high...err...edge that you crave so much.

[John Schtrumpf]

Yeah, but it's like a heroin addiction in that you have to keep rocking it more and more to ensure that you continue to hit the high...err...edge that you crave so much.
I have watched a sharpening video of his. He works rapidly and does a lot of strokes. My theory is, if you do enough strokes, eventually you will have hit the edge a few times.

As for me, my muscle memory is unreliable. So I register the existing flat bevel on the stone and work that.

[Don Dorn]

I'm the odd man out. Having tried several methods over the years, I had settled on Rob Cosmans for awhile. Now, I'v'e been using the Sellers method for years now. I really like it because with three diamond stones and stropping in about 5 minutes leaves me with an edge that slices through receipt paper with just blade weight and seems to keep through an average project.

As to the convex, many are probably right in that it happens incidental to the process as opposed to it being intentional. That said, it doesn't bother me. When they get too blunt, I just grind, just as I would when you get too much of a secondary bevel on a flat or concave iron. I use the Ian Kirby system on a slow speed grinder and because I stick with Stanley irons, it takes no more than about five minutes. In any event, it works for me for both chisels and plane irons.

For router plane blades as well as beading cutters, I follow Chris Schwarz way of "reversing" it. I sharpen the flat side until a burr is created on the work side. Then, just rub that off with a slip stone or final stone. I think I"m done with learning or experimenting with sharpening and grinding. It's faster than its ever been and I'm very happy with the results.

[Robert Hazelwood]

I don't make convex bevels on woodworking tools, but I do use them on hatchets and axes. I tend to think of them as a blended set of bevels, and use the same philosophy as I do with a flat primary and secondary bevel. That is, the majority of the metal is removed behind the edge. If you remove too much near the edge you will end up with an obtuse edge. With the coarse stones I work a convex bevel starting at the base of the bevel and working closer to the edge, but not quite there. With the penultimate stone I will do much the same, but at the end of the step I will just work the edge enough to raise a burr, careful not to overshoot the existing angle. Then I will refine the edge and remove the burr with finishing stone.

I think you could do much the same with a chisel or plane iron. In fact, you could sharpen in the Sellers style but deliberately work to a lower angle than you want to finish with, then hone a small secondary bevel at your desired edge angle.

I would not give up on free handing. It's more enjoyable, less cumbersome, and kind of empowering to do it freehand. You just need to keep your angles under control. I really think the reference blocks I mentioned in an earlier reply would be helpful (Derek also posted a different version, either would be effective). Getting a grinder would be useful of course, and freehand honing at a steady angle seems easier than trying to return to the same angle on every stroke after sweeping through a range of motion.

[David Bassett]

... Would one of the $40 6" grinders from the BORG be sufficient, with a 60-grit aluminum oxide wheel as suggested by Doug? ....

For home / hobbyist use I don't think those grinders would be a problem, unless you got an unusually poor example. (There is a reason industry doesn't use them though! Less power, cheaper bearings, more runout, etc. etc. etc.) The biggest problem with those cheap grinders are the wheels, which are not friable enough for our harder steels, and their tool rests, which are... inadequate. The hard gray wheels that come with the big box store grinders are designed for mild soft steel and don't shed dull particles quickly enough to stay sharp and cut harder tool steels. It seems like turners more commonly use dry grinders and the go to cheapie there seems to be the Rikon 8" which goes on sale for $100 every so often. It comes with less awful wheels, so you don't have the expense of upgrading those right away. (Also, there seems to be a greater selection of CBN wheels in 8", for when you get tired of ever shrinking friable wheels. :) ) As for the tool rest, there are a number of good options out there. Some will even argue you can freehand on a grinder as well as on stones, but even free handing my angle I like a tool rest to brace my hand against. (Brushing the wheel is... unpleasant. Never tried catching a finger in the mechanism and I make very sure that I won't!)

[Patrick Chase]

It seems like turners more commonly use dry grinders and the go to cheapie there seems to be the Rikon 8" which goes on sale for $100 every so often. It comes with less awful wheels, so you don't have the expense of upgrading those right away.

I've never used 1/2 hp Rikon (which I suspect is what you're referring to) but I have the 1 hp version that usually goes for $200 or so. It's a remarkably nice grinder even considering the cost. The wheel bushings are reasonably large and solid discs vs the stamped sheet metal ones on cheaper grinders, and the result is improved trueness/tracking. If you're going to upgrade to CBN anyway then this may not matter, as CBN wheels tend to run true to begin with, but it's a significant benefit for conventional wheels.

The Rikon wheels are OK and significantly better than Borg fare, but on the hard side compared to the ones that WWing retailers sell. The Rikons have White Alumina (WA) abrasive and grade N binder. For comparison LV's "white friable" wheels are also WA, but grade H. I've dressed a couple of my Rikon wheels for use with concave tools (their hard binders are advantageous for holding profiles) but you have to be a little careful to avoid burning. If you use a light touch and dress reasonably frequently it's not a big deal, though.