Sharpening using the ruler trick

[David C]

Steve,

I find your thoughts on the narrow ura most interesting.

My feeling about the ruler trick is that it massively increases the probability that the wire edge will be properly honed away on the polishing stone. I see it float away either on the stone or on the sponge cloth that I clean the blade with.

It avoids the stiction of polishing stones and I find no need to strop.

What are the chances of the blade back and stone being perfectly flat to ensure contact at the edge? Not to mention the huge saving of work at the blade back prep stage.

best wishes,
David Charlesworth

 

[bugbear]

I've found that a back bevel of only a few degrees results in an edge that seems sharper than an edge honed on the same stone with the blade back kept flat.

I suspect that may be due to the "normal" method of a flat doesn't (in fact) allow the abrasives to work the back OF THE EDGE as much as we've historically assumed; even if the back is made fully flat, there is wear on the back from use.

At the least in theory (therefore) a flat abrasive will not work fully to the edge.

BugBear

 

[ali27]

Ali,

I grind plane blades at 23 degrees.

Get a wire edge on 800 grit stone at 33 degrees.

Change projection to 35 degrees and polish tip of blade on 10,000 stone.

THEN do ruler trick on 10,000 stone only.

This is very quick, as little work is being done on each stone.

I have found recently that I can flatten Plane Blade backs to remove manufacturers grinding marks on 800 stone, and then go straight to ruler trick.

David Charlesworth

Thanks for the advice Mr Charlesworth. Still Mr Charlesworth,
would you not agree that if the jig would allow us to sharpen a small
back bevel without removing the blade from the jig, that would makes things even easier?

Why do you go from 23 to 33 degrees? I know little about these things.
I understand that in a bevel up plane changing the cutting angle makes a
difference, higher degree for harder woods. What difference does it make increasing the cutting angle in a normal plane?

Regards,

Ali

 

[Mr Ed]

On a bevel down plane the angle of honing is more to do with finding an angle that suits the steel of the blade to hold its edge best. For example, the general view with A2 steel is that it performs best somewhere between 30 and 35 degrees.

The reason for the minute increase in angle is that it allows a final polish to be applied to the very edge of the bevel so you know that you have refined the part where the 2 edges intersect, whilst minimising the work that would be required if you were to hone the entire bevel.

Ed

 

[martin99]

There is a big selection of steel thicknesses available here http://www.cromwell.co.uk/category_page/05010209 if you can't find a suitable ruler.

 

[woodbloke]

performs best somewhere between 30 and 35 degrees.

The reason for the minute increase in angle is that it allows a final polish to be applied to the very edge of the bevel
Ed

My final bevel is set at 32deg on A2 steel. In my experience, a honed bevel with A2 at 30deg causes the edge to crumble, which is the reason I have a micro bevel just a tad higher, so the angles on my blades are primary bevel at 23deg (ground on the Tormek), honed bevel at 30deg and a micro-bevel (no more than a couple of swipes) at 32deg, with the ruler trick being used on 10000g Spyderco ceramic stone - Rob

 

[ali27]

On a bevel down plane the angle of honing is more to do with finding an angle that suits the steel of the blade to hold its edge best. For example, the general view with A2 steel is that it performs best somewhere between 30 and 35 degrees.

The reason for the minute increase in angle is that it allows a final polish to be applied to the very edge of the bevel so you know that you have refined the part where the 2 edges intersect, whilst minimising the work that would be required if you were to hone the entire bevel.

Ed

Ok thanks, that is clear.

 

[David C]

Grinding at 23 degrees instead of 25 allows me to squeeze in some extra honings before regrinding. (Perhaps 7 to 10).

Sharpening at 35 instead of 30 gives a slightly stronger edge. It reduces the clearance angle in a bevel down plane, from 15 to 10 degrees. This is similar to a block plane and I think perfectly acceptable.

David

 

[andyavast]

I am interested to hear how you fellas treat A2 low angle block plane blades?

I use my LN low angle block for end grain only so have always kept my micro bevel to 27 degrees having always believed a low effective pitch and tightly closed mouth is the only way to deal with end grain.

I have found the edge fails pretty quickly and assumed this was par for the course.

is this the case?

Andy

 

[Vann]

...so have always kept my micro bevel to 27 degrees ...

My understanding is that for a bevel that low, you need O1 steel (not A2), and Clifton make the best there is.

Cheers, Vann.

 

[gidon]

I think it would be great if a quality jig would be made
that can sharpen a backbevel of about3-5 degrees
without having to remove the blade from the jig while sharpening
the front bevel.

I have the newer Veritas jig which is quite good, but takes too much
time to do the backbevel and also the lowest is a 10 degree backbevel.

I have to remove the blade. Loosen the big knob and bring it from ''2''
to ''3'' to do the backbevel thing.

I suck at describing these things.

Ali

Ali - have a look at a post I made a while back:
https://www.ukworkshop.co.uk/forums/view ... 215#280215

Cheers
Gidon

 

[ali27]

I think it would be great if a quality jig would be made
that can sharpen a backbevel of about3-5 degrees
without having to remove the blade from the jig while sharpening
the front bevel.

I have the newer Veritas jig which is quite good, but takes too much
time to do the backbevel and also the lowest is a 10 degree backbevel.

I have to remove the blade. Loosen the big knob and bring it from ''2''
to ''3'' to do the backbevel thing.

I suck at describing these things.

Ali

Ali - have a look at a post I made a while back:
https://www.ukworkshop.co.uk/forums/view ... 215#280215

Cheers
Gidon

Gidon,

Thanks for the link. Nice idea. Makes me think about having
small wheels on the back of the jig.

Ali

 

[gidon]

Even without wheels it works fine.
Cheers
Gidon

 

[David C]

Gidon,

Very ingenious!

Is that a Shapton Glass Stone I see?

best wishes,
David

 

[gidon]

Thanks David! No it's a Spyderco ceramic stone.
Cheers
Gidon

 

[woodbloke]

Thanks David! No it's a Spyderco ceramic stone.
Cheers
Gidon

...and very good they are too, if you get a flat one - Rob

 

[ali27]

Thanks David! No it's a Spyderco ceramic stone.
Cheers
Gidon

...and very good they are too, if you get a flat one - Rob

I had never heard about the Spyderco stone. Googled it and found this
interesting comparison:

http://www.tzknives.com/razoredges.html

Seems the green buffing compound(10 strokes)produces a fantastic
edge. The spyderco ultra fine looks a little better than a 12000 chinese
waterstone.

Ali

 

[gidon]

Nice pics - thanks Ali - it is the UF one I have. And IIRC they (the UFs) are usually flat - although they have machine marks that I grinded out. The lower grits were a bit more variable when I last looked.
Cheers
Gidon