Sharpening Secondary Bevel: Honing and Polishing

[Ned Mcbee]

Now that I'm tryin to systematize my sharpening regimen the one area of greatest confusion seems to be all the various angles I have to keep square ... not merely on the blades but more importantly in my head. With a Lie Nielsen honing guide and protrusion jig with shim, I finally have a tool capable of repeatable precision (my Eclipse clone's screw was chewed as it struggled with its blade securing duties).

When I contemplate all the various angles for different blades, and the subset of primary, secondary, and tertiary bevels Chris Schwarz's idea of a single bevel angle for all blades looks promising. I've not yet thrown in the towel and adopted a single sharpening angle and will make an effort to apply a different angle to different blades as needed. I'm also still new to cambering a blade only having tried it once. I primarily woodwork periodically in great bursts and the lack of daily continuity interferes with the formation of memory and habit to lock in a system. I'm also new to cambering having only done it once on the last honing my #4 plane, but it's time to make that a permanent sharping feature.

don't have a dedicated sharpening area. I'll need to have a chat sheet of sorts and/or write on my blades the angles so I can keep confusion at bay.


However, I want to get some feedback on what how others are altering the bevel angle for subsequent stages of the honing process.

For example, assuming a blade with a primary grind at 25° and targeted for a secondary bevel at 30°:
1) Primary Bevel: the 25° need not be honed or polished, correct? It could conceivably be established on a coarse stone and left as is.
2) Secondary Bevel: of 30° is honed (for ex. with a 1k +/- stone) to raise a wire edge.
3) Polishing Stage: do you, a.) maintain the same 30° bevel angle but just polish it, or b.) add a tertiary bevel of a couple more degrees - in this example to arrive at bevel of 32° [for ex. by use of a shim in a protrusion jig or by other measurement]? Or other?

Thereafter when the blade requires routine touching up from use, do you only do a few passes on the polishing stone at 32° if using a tertiary bevel (or at 30° if your sharpening routine only uses a secondary bevel)? Or do you raise a wire edge on the honing stone at 30° first?

[FYI, I'm still working on King water stones from the '90s a 1k and 6k. Hoping soon to upgrade them].

[Robert Hazelwood]

Those angles sound about right for a plane blade. I sharpen freehand but it works out to be pretty close to your angles.

The primary is normally ground on a power grinder or on a very coarse stone (like a Crystolon) or with coarse sandpaper on a flat surface. This can be done with an extremely coarse grit, no benefit to a polish. I grind at 20 degrees, but 25 is probably more common and less work if you are grinding by hand.

The secondary establishes the edge and is what you will start with on most sharpening sessions. You'd start with something like a 1k synthetic waterstone or Fine India. Sharpen until you raise a wire edge. I then move to a finer stone (soft arkansas or maybe 4-5k waterstone) and refine that for a few strokes. I aim for 30 degrees.

Then I increase the blade angle just a hair and polish on the final stone (Translucent ark or 8k+ waterstone). This "tertiary bevel" should be almost invisible, and easily removed with your 1k/India stone at the next sharpening. Probably ends up at about 33 degrees.

Then I work the remaining wire edge down by alternating very light bevel and back strokes. A few strops on clean leather and it's good to go.


Notes:

After several sharpenings the secondary will get larger, and it will take more work to create a wire edge. That's when you go to the grinder or coarse stone and work the primary until the secondary is almost (but not completely) gone.

If you are using fast-cutting synthetic waterstones with a honing guide you may not need to do a tertiary bevel. The fine stones might polish the secondary quickly enough that its a waste of time to reset the guide for the 3rd bevel. With slow-cutting oil stones and freehand sharpening I think it's a good idea.

The ideal final angle will be based on experience. If the blade chips/rolls then it needs another degree or two. Keep increasing until you almost never get edge damage. For most blades that's around 32/33, some can be lower or higher.

[Curt Putnam]

You are correct - the primary bevel can be left coarse. You might wish to do a web search for the "Unicorn Method". Suggest your next upgrade should probably be a 13K or higher. I consider a 6K to be a mid grit stone and suggest finishing with a strop until you get the next stone. When your secondary bevel gets too large, a power grinder is the most efficient way to grind off the excess metal.

[Ned Mcbee]

You are correct - the primary bevel can be left coarse. You might wish to do a web search for the "Unicorn Method". Suggest your next upgrade should probably be a 13K or higher. I consider a 6K to be a mid grit stone and suggest finishing with a strop until you get the next stone. When your secondary bevel gets too large, a power grinder is the most efficient way to grind off the excess metal.

Thanks.
I'll look into the unicorn.
Yes, next up on my list of upgrades is two new stones. Been looking into Sigma Power II but that's another thread.
No power grinder here.

[Ned Mcbee]

Then I increase the blade angle just a hair and polish on the final stone (Translucent ark or 8k+ waterstone). This "tertiary bevel" should be almost invisible, and easily removed with your 1k/India stone at the next sharpening. Probably ends up at about 33 degrees.

...

If you are using fast-cutting synthetic waterstones with a honing guide you may not need to do a tertiary bevel. The fine stones might polish the secondary quickly enough that its a waste of time to reset the guide for the 3rd bevel. With slow-cutting oil stones and freehand sharpening I think it's a good idea.

To use a tertiary bevel or not - and adjust bevel angles accordingly - has been an area of uncertainty. My stones are old tech and also not very fine/high grit.
Thanks for your recommendations.

[Gary Focht]

I just unicorned my chisels this past weekend. They have never been better. Did a few test dovetails and they performed flawlessly and sharpening is very quick.

[Warren Mickley]

It sounds as if you have been reading too may bloggers.

I have used a single, flat 30 degree bevel for over fifty years. Paring, chopping, mortising, planing, molding, carving, turning, etc. Much more effective, much less confusing.

[Joe Bailey]

It sounds as if you have been reading too may bloggers.

I have used a single, flat 30 degree bevel for over fifty years. Paring, chopping, mortising, planing, molding, carving, turning, etc. Much more effective, much less confusing.

Amen to that, though I'm not quite at fifty years yet.

[Tom M King]

I'm only at 47 years, but flat bevels for me too. I do use a few different ones though.

[Stephen Rosenthal]

I just unicorned my chisels this past weekend. They have never been better. Did a few test dovetails and they performed flawlessly and sharpening is very quick.

Ditto. Can’t believe how sharp they are and how quick the process is. I’m going to try it on an old Stanley plane blade. If it works as well, I’ve got some sharpening to do.