Convex bevel a la P. Sellers

[James Lehr]

Hello all, I've been watching Paul Sellers' videos quite a bit lately and he finally had me convinced of the quickness of diamond stones on the bench and "get right back to work". That said, I bought a set of coarse, fine, and x-fine DMT stones and made up my leather strop (Just like Paul's setup on the video). I must have watched his video on sharpening plane irons at least 30 times before attempting; I just recently replaced my Stanley No. 4 iron with a Hock Iron and Chipbreaker. Previously I have used a Norton 1000/8000 waterstone with the "ruler trick" and got really great results. I don't have water in the garage so I thought having the DMT's around would make sharpening easier. Anyway, my first attempt at freehand sharpening my plane iron seemed ok (at first); i had the convex bevel and the feathered wings. I thought i had a sharp edge (felt the burr) and stopped and tried it out. I could not get a shaving to save my life. Now I'm frustrated bc I've got a plane iron that has this crazy convex bevel and I've spent about an hour now trying to re-establish the bevel at 30 degrees using my honing guide instead of freehand.

Whew that was a lot. My question is whether anyone uses Paul's freehand method and gets positive results? I think at this point I will go back to my honing guide; i'll keep the DMT stones and start using the strop and see if I can get a consistent sharp edge or if i have to go back to waterstones. Thanks.

[Jim Koepke]

This is another one of those sharpening questions that ends up with a lot of disagreement and sometimes heated exchanges.

The convex bevel seems to work for some, but others tend to get it too convex and then with a bevel down plane there isn't enough clearance angel behind the edge of action (for lack of a better name) and a shaving can not be produced.

My theory on sharpening is to consistently make a sharp edge before trying any of the variations. Very few of my blades have an intentional second bevel. Since most of the time my blades are honed free hand there may actually be a slight secondary bevel or even some convexity.

In my experience once the back of the blade is good to go there isn't a need for the ruler trick.

For me it is simple, if a blade isn't cutting, it is because it needs sharpening. It isn't because it is too convex or the back bevel from the ruler trick got rounded or the secondary bevel isn't right.

Keep it simple, Keep it sharp.

jtk

[James Lehr]

I think you hit the nail on the head with having the bevel "too convex". The edge was sharp but in the plane I couldn't get a shaving. On the other hand, I'm not sure why the blade wasn't sharp after trying to take shavings multiple times. Is it possible to dull the wire edge if the bevel is too convex and not allowing the edge to cut? I wonder because I kept extending the blade and then I'm like 'something is wrong here'. Also, the weird thing is that when I first started hand planing I tried to mimic Rob Cosman's style of freehand sharpening with the Norton waterstones and that was ok but still inconsistent. I like the idea of a consistent sharp edge and my $10 honing guide seems to give me that. Hopefully I can just keep using it and try transferring to the diamond stones.

BTW, sorry if this is a contentious issue; I read a couple previous posts about Paul's convex bevel but the discussions were about chisels and not plane irons.

[Derek Cohen]

Hi James

The question for you is "how did you apply this technique?". Did you just freehand it willy-nilly, or did you employ some way of accurately determining the angle you created at the edge of the bevel? I can imagine many trying to emulate Paul Sellers and instead creating a cutting edge somewhere around 45 degree while swearing that they never raised the blade over 30 degrees.

I use this method for mortice chisels. These are chisels with thick shafts and 20 degree primary bevels. They are too difficult to stick into a honing guide to create a secondary of 35 degrees .. so the rounded bevel method suits them. I do not want a bevel of 28 degrees - it will fold in my hardwoods. I do not want a bevel of 40 degrees - it will not slice into wood well.

To achieve a reasonably accurate 35 degrees, I employ a sliding bevel as a guide. This is set at 35 degrees at the near end of my stone. I start the stroke at the far end of the stone, ensure it is around 20-25 degrees (lower than the sliding bevel), and draw it towards me. When it ends, the shaft must not be above the bevel angle.

The disadvantage of the PS system is that it relies a lot on muscle memory for accuracy. This takes time to achieve. One is also honing more steel than when honing a micro bevel on a hollow friend. The advantage of the hollow grind is that it is self-jigging. And the advantage of a great hollow grind is that there is minimal steel to hone, which makes for sharp and quick. See: http://www.inthewoodshop.com/Woodwor...ningSetUp.html

Regards from Perth

Derek

[Matt Knights]

I use the convex bevel all the time on everything, it gives me shaving sharp edges. Derek is right the the hardest part is to gauge the 30 degrees accurately, I started with a 25 degree flat bevel and then exactly as Paul does as I pull the iron back towards me I lift it off the stone a little (aprox 5 degrees), it is really easy to lift too much and remove the clearance angle. Practice with an old iron as stated above once the muscle memory is there it takes aprox 30 seconds to hone an iron ready for work. I use the convex bevel as I have no way of regrinding back to 25 when the micro bevel becomes too big, but after a couple of years of using it now I dont think I would grind even if I has a means to..

Matt

[Kees Heiden]

No I don't use the PS method, but it should be possible to get it working. Here is another video which might explain it better:

[Warren Mickley]

Sellers says to start at 30 degrees and then lower the iron so the angle is somewhat less than 30 at the back of the bevel. Had you done this, it would not have been any trouble sharpening at 30 degrees with your honing guide. The evidence is you started at something like 40 or more at the bevel and that is why it is so much work to sharpen at 30 degrees again.

Sellers himself seems to have a very poor concept of 30 degrees. If you watch his videos he sometimes seems closer to 45 than 30 degrees and if you look at his chisels they also look much to blunt at the tip. You could find someone better to copy.
sellers chisel 2012.jpgsellers chisel 1.jpg

[Brian Holcombe]

I used this method early on, I initially found it successful but quickly found it to be tough to get good and consistent results.

Paul's method must include a lot of cutting behind the bevel to be able to maintain this practice and consistently draw a sharp edge in the high grit stones that actually functions.

After having used both I much prefer the ability to set an angle and know what the results will work like. I do not need to add additional variables to the equation of plane tuning. It also took my sharpening time down significantly and I spend much less time returning to the stones for more work.

[george wilson]

You MAY have gotten the edge so convex that the cutting edge is not able to contact the wood,if you see what I mean. I only EVER sharpen freehand and have no trouble like that because I learned to judge angles freehand.

I use a diamond stone,then black,then white Spyderco ceramic stones. Then,a few licks on an MDF strop with Lee Valley green buffing compound on it. Beware of some green compounds. Not all are the same. Lee Valley uses superfine green chromium oxide. Some also contain coarser abrasives.

The MDF strop does not have a soft surface like leather,and does not contribute to the edge getting more rounded.

[Jim Matthews]

x or the back bevel from the ruler trick got rounded jtk

+1 on this. The ruler trick doesn't look like much steel, but it's enough to throw off this method.

You need to grind the steel back past the back bevel and verify the back is flat.
Note that the stropping step requires considerable downward pressure,
and vigorous 'pulling' to work.

If you swing your arms through an arc on this step, you will round the edge.

I have it on good authority that the stropping step can be done quite
well on oiled leather, without any rouge or polishing compound.

[Daniel Rode]

I'm no expert but Seller's chisels "look" too blunt to me also, but watching him they seem to work well for chopping and paring. I've experimented with sharpening this way and it seemed to work well enough but I didn't find it any faster, easier or sharper than using a flat primary with a secondary a couple degrees steeper.

Sellers says to start at 30 degrees and then lower the iron so the angle is somewhat less than 30 at the back of the bevel. Had you done this, it would not have been any trouble sharpening at 30 degrees with your honing guide. The evidence is you started at something like 40 or more at the bevel and that is why it is so much work to sharpen at 30 degrees again.

Sellers himself seems to have a very poor concept of 30 degrees. If you watch his videos he sometimes seems closer to 45 than 30 degrees and if you look at his chisels they also look much to blunt at the tip. You could find someone better to copy.
sellers chisel 2012.jpgsellers chisel 1.jpg

[george wilson]

You can get by without any strop except a sheet of paper,like I did when I was a kid with no money. You just have to keep at it longer. I often touch up my pocket knife when sitting in my recliner,by stropping it on the back of my wide leather belt. I pull out the several inches of belt that go beyond the buckle,and use it as a strop. It has no compound on it. If the edge is ALMOST razor sharp,I can bring it back to razor sharp without going out to the shop. My pocket knife is plain carbon steel. I have thought about rubbing a bit of the green compound on the back of my belt,but haven't done so as I don't want to get the compound on my hands or clothes. If I did rub compound on it,it would only be a very small amount. I don't want to end up ingesting a little chrome oxide.

My belt is made from good strong harness leather,made by the shoe maker in the museum. The suede side is pretty smooth,rather than fluffy like most. It has a bit of tallow in it.

[Jim Matthews]

George, how do you feel about using a strop with only a little oil - instead of rouge?

[Brian Holcombe]

You MAY have gotten the edge so convex that the cutting edge is not able to contact the wood,if you see what I mean. I only EVER sharpen freehand and have no trouble like that because I learned to judge angles freehand.

I use a diamond stone,then black,then white Spyderco ceramic stones. Then,a few licks on an MDF strop with Lee Valley green buffing compound on it. Beware of some green compounds. Not all are the same. Lee Valley uses superfine green chromium oxide. Some also contain coarser abrasives.

The MDF strop does not have a soft surface like leather,and does not contribute to the edge getting more rounded.

This is certainly the case. It's easiest for me to simply know the angle I'm working, it removes my tendency to cheat by raising the back, something I do without a conscious intention.

[george wilson]

As mentioned,my belt has a bit of tallow in it,so I'm already doing the oiled leather strop,sort of.

Since I don't want to have to strop a long time,I prefer to use a bit of green compound. When I was a dirt poor kid,I spent hours stropping a 50 cent chisel sharpened with a cheap,grey hardware store stone. I used note book paper. Eventually,I got the chisel real sharp,but,being a cheap chisel,it would not stay sharp for a long time. So,I spent a lot of time stropping! Hard head paid off eventually. What other teenager was stupid enough to spend hours sharpening a chisel? Never did learn how to dance!!!

At the time,with no one to teach me,I wasn't even aware that there were better stones available. Good thing,as I could not have afforded them anyway.