back bevels

[engineer one]

one of the reasons i started this thread was that the ian kirby article
had some interesting drawings and data within it,showing
clearance angles and also stated that the more back bevel you
have the harder it is to push the plane on figured wood,
which i guess might make you think that the blade is not as
sharp as you had hoped strange hey/ :?

if you read the TLN sharpening book,or that by Leonard Lee, and indeed
others i have read, to sharp an angle seems to cause problems and
change edge life.
paul :wink:

 

[MikeW]

...Wiley ... hoping Alf doesn't punch my ticket and send me to the corner for a while.

We don't even have a spittoon here, so you are probably safe--for now :lol:

As regards wear bevels on low bedding angles, yep, greater wear and faster than Holtley's 22.5*, which also is faster than a 45* bedding angle.

A BB, regardless of bedding angle increases the rapidity of the wear bevel's effect upon edge sharpness. Doesn't matter whether it be a BD or BU oriented blade. However, I believe that a BD plane has the edge (sorry) as regards edge retention, all bevel angles being comperable.

Mostly this is an academic excercise. It only really becomes a practical issue if someone is pushing the limits between honings. I hone frequently and or swap out blades to stretch out a planing session, so I could care less.

Well, I guess another slightly practical issue as regards the size/thickness of a wear bevel is one of honing time. More metal to remove during honing results in more time honing. But I think this issue with HC blades is moot and only becomes noticable with A2 and harder steels.

IMO, using A2 steels past the point they should be honed is one reason for the growth of better grades of stones and motorized equipment--it's just plain harder steel and takes longer to hone.

For me, the moral of the story is to hone frequently and before edges dull fully, regardless of the type of edge tool.

Well, now my head hurts too. So I'm going to go make some handles. Rasping is a relaxing activity. And seeing how I cannot sharpen my rasps, I don't have to worry about it :wink:

Take care, Mike