Flattening, polishing and friction.

[bugbear]

...I do think that flattening is usually achieved sufficiently every time you turn a chisel over to remove the burr -

Unless your stone were to have a hollow, in which case you're creating a convex back as well as a convex bevel. :lol: :lol: :lol:

BugBear

I've been thinking about this a bit recently and would a slightly concave arkansas/waterstone give the desired camber to a blade that we emulate with jigs, techniques?

If the hollow were uniform for the full length of the stone, and just the right size for the blade camber you desire, and you want the same camber on each and every one of your planes, that might work well.

BugBear

 

[Jacob]

......

Unless your stone were to have a hollow, in which case you're creating a convex back as well as a convex bevel. :lol: :lol: :lol:

BugBear

I've been thinking about this a bit recently and would a slightly concave arkansas/waterstone give the desired camber to a blade that we emulate with jigs, techniques?

If the hollow were uniform for the full length of the stone, and just the right size for the blade camber you desire, and you want the same camber on each and every one of your planes, that might work well.

BugBear

Doesn't have to be so specific. In reality, if you are actually doing these things, they work out differently. Not least because a hollowed out stone tends to be hollow in the middle but flatter at the ends and edges, like a shallow bath. Which means all sorts of things are possible including accurate flattening - across the top of the bath as it were.
They vary depending on the user. I have one which is deeply hollowed end to end but square across. Probably used by a butcher or somebody sharpening big blades. I'll never know!

 

[wem]

Concave grind from the wheel?

Yes, sorry.

 

[wem]

The illustration showing the grind and the two points of contact with the stone along the edges.

 

[Phil Pascoe]

That's obscene! truly pornographic! Everyone knows it should be convex, not concave!

 

[GazPal]

I moved the tool rest round to the side and used the flat side of the wheel to take the concavity out after taking the material off.

Grinding on the side of the wheel is bad news. Unless the wheel is designed for it, which very few are.

If you really want a flat grind- http://www.ebay.co.uk/itm/Viceroy-Sharp ... 20c88fc357

Clocked a good few hours on one of those, messy bloody horrible thing...

JH

Grinding on the side of a low speed wet wheel is normally safe, but never if using high rpm. The vertical approach is much the same as using a horizontally mounted wet wheel.

Ye olde worlde Viceroy flat grinders were a bonus to have around in a busy workshop, as you could basically set up a blade to grind and allow the tool to do it's job while you got on with your work. Very little mess - if any - unless set up poor or the machine was faulty.

------------

 

[Jacob]

Thanks Jacob. I have also been reading Krenov's books and he achieves a secondary bevel by relying on a concave grind from the wheel, this he rests on his stone and hones using small left to right or circular movements, nothing more, only the outer edges of the hollow grind contact. I have found this gives me much better results that last longer than any primary/secondary honing guide system. I suppose it is whatever works for you? Unfortunately it can be an expensive learning curve.

Edited because i meant concave.

Wel yes it'll work but only if you can hollow grind accurately enough to give you the 30º edge and don't mind the edge weakened by hollow grinding.
A lot of these methods are predicated on the assumption that people can't easily hit an angle of 30º freehand. I don't believe this is true and in fact most of the work these same people do is much more difficult and requires a much higher level of craft and hand/eye ability.

 

[wem]

Wel yes it'll work but only if you can hollow grind accurately enough to give you the 30º edge and don't mind the edge weakened by hollow grinding.
A lot of these methods are predicated on the assumption that people can't easily hit an angle of 30º freehand. I don't believe this is true and in fact most of the work these same people do is much more difficult and requires a much higher level of craft and hand/eye ability.[/quote]

He used a rest made from wood.

 

[Jacob]

Wel yes it'll work but only if you can hollow grind accurately enough to give you the 30º edge and don't mind the edge weakened by hollow grinding.
A lot of these methods are predicated on the assumption that people can't easily hit an angle of 30º freehand. I don't believe this is true and in fact most of the work these same people do is much more difficult and requires a much higher level of craft and hand/eye ability.

He used a rest made from wood.

Glad to hear it! :lol: