Honing angle for Bench Planes

[EricU]

I imagine that most bench planes were sold to carpenters here in the states, even the big ones. Probably where the 25 degree angle came from

[Derek Cohen]

A bevel angle for planing soft pine? That is a wood?
Just kidding. Allan, I accept that you can use a 25 degree bevel but, regardless of the wood, you would be better served with a 30 degree bevel. Even soft woods benefit from a longer lasting edge.

Bevels from the factory that arrive at 25 degrees are generally intended to receive a secondary bevel of 30 degrees ... "grind at 25, hone at 30".

The reserch I have done shows a significant improvement in edge longevity when taking it up to 30 degrees.

Regards from Perth

Derek

[Joe Bailey]

A bevel angle for planing soft pine? That is a wood?
Just kidding. Allan, I accept that you can use a 25 degree bevel but, regardless of the wood, you would be better served with a 30 degree bevel. Even soft woods benefit from a longer lasting edge.

Bevels from the factory that arrive at 25 degrees are generally intended to receive a secondary bevel of 30 degrees ... "grind at 25, hone at 30".

The reserch I have done shows a significant improvement in edge longevity when taking it up to 30 degrees.

Regards from Perth

Derek

Some support for Derek's theory, from Stanley's reference charts:

[Timberwolf]

It depends on the steel somewhat.  O1 steel can be sharpened to a 25 deg bevel without sacrificing durability of the edge.  A2 seems to want 30 deg, because smaller angles don't offer enough resistance to chipping on the edge.  The bevel angle on a bevel-down bench plane does affect the clearance angle of the cut.  Too steep a bevel angle and you'll get more wear on the bevel in use, and that may become noticeable as the wear increases as increased resistance to pushing the plane.  It's a minor effect, but it is part of the equation.

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It depends on the steel somewhat.

This.......I grind to 25* or lower, then let the steel tell me how low it likes to be.. Micro-bevel to what angle it can tolerate. Same procedure for knives and other edge tools...Lower takes less effort {sharper} in cutting if the steel can stand it. Everything in life is a trade-off.

[Bill_Houghton]

On a bench plane, where the effective cutting angle is the bedding angle, is the blade really "sharper" with a 25 degree bevel on the back of the blade (as it presents to the wood) than with a 30 degree bevel?  I know the angle has to be sufficient to provide some clearance behind the edge, relative to the sole of the plane, but am having trouble understanding how it will affect cutting action.

[omark]

On a bench plane, where the effective cutting angle is the bedding angle, is the blade really "sharper" with a 25 degree bevel on the back of the blade (as it presents to the wood) than with a 30 degree bevel?  I know the angle has to be sufficient to provide some clearance behind the edge, relative to the sole of the plane, but am having trouble understanding how it will affect cutting action.

Exactly. There is no tradeoff for BD blade.
My answer to original question: why would you sharpen to 25 if you can to 30?

[Rob Young]

Last in line : I grind at 25* (-ish) and hone at 30* (-ish) for bevel down blades, most of my bench chisels and most of my joinery/moulding plane blades.

Grinding is usually on a wet grinder these days but I do have a hand-crank grinder with a small wheel that is great fun. But some things like router plane blades I just "grind" on sandpaper stuck down to granite. Maybe once in 5 years I've had to do that.

Exceptions to the 30* honing are mortise chisels (higher, more like 35*) and a few chisels that get lower and higher honing.

I have a few bevel up planes. The small block planes get the same 30*-ish honing. But for a few of the larger BU planes I have extra blades and have various angles to play with. I don't use them as much as I did a few years ago as I'm getting the performance I need from my BD planes.

Honing is usually on oil stones (go-to is a fine India) without jig. Stropping on the leather wheel of my wet grinder or a board-mounted leather strop, whichever is closer at hand. But I have diamond stones and some diamond paste that is fun to play with occasionally too, mostly for flattening and polishing backs. And finally I do have an Eclipse-clone jig for those days when things just don't go right. Thankfully, those are few and far between these days. Learning to hone without a jig was one of the best things I think I could have done for improving my handwork speed.

[Admiral]

Last in line : I grind at 25* (-ish) and hone at 30* (-ish) for bevel down blades, most of my bench chisels and most of my joinery/moulding plane blades.

 Stropping on the leather wheel of my wet grinder or a board-mounted leather strop, whichever is closer at hand.    

I've said this before, but try a final stropping on a piece out of a brown paper grocery bag on a flat surface.  That kraft paper has some micro abrasives in it from recycling, and I'll tell you, it really does work.  I keep a piece on my jointer bed.  Just do the back flat, then hit the angle of the bevel such that it shaves the top layer of the paper a bit.

[Rob Young]

I've said this before, but try a final stropping on a piece out of a brown paper grocery bag on a flat surface.  That kraft paper has some micro abrasives in it from recycling, and I'll tell you, it really does work.  I keep a piece on my jointer bed.  Just do the back flat, then hit the angle of the bevel such that it shaves the top layer of the paper a bit.

Yep.  Done that.  Also used "white" paper bags, copy paper and even just plain old MDF.  They all work.  Some work faster than others based on the steels.  Since I've got a mix of O1, W1, A2, D2 and rando-cheapo-hardo-no-idea, I really like the power strop.

And I've mostly given up on the green crayons of stropping compound in favor of Autosol polishing paste.  Seems to work better for me when used on leather. No scientific testing, just how it feels. 

Always wondered about "cheap" toothpaste as a stropping compound.

[Timberwolf]

I've said this before, but try a final stropping on a piece out of a brown paper grocery bag on a flat surface.  That kraft paper has some micro abrasives in it from recycling, and I'll tell you, it really does work.  I keep a piece on my jointer bed.  Just do the back flat, then hit the angle of the bevel such that it shaves the top layer of the paper a bit.

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I think it's the silica in paper and cardboard that makes it work so well...and it dulls the edge just as quickly when you cut it...Very few materials can dull edges faster than cutting cardboard..Knife makers at one time determined how good a knife steel was by how many inches of cardboard it would cut cleanly.