'Shapeing' Plane Blade

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I've often wondered what the correct way was to round-off those corners and I'm grateful to have discovered that in this thread. :)

In the past, I've done it using the narrow edge of an oil stone (to prevent grooving the face) with the blade held at 90° to it (parallel to the wider face)... For some reason, this affected the cutting performance of my smoothing plane and I ended up re-grinding it back to give me square corners... :roll:

I'll give the 45° tip a go next time though, thanks. :wink:
 
graween":n42azfjk said:
I don't really understand Alf about the scraping action of the corner. I'd be interested in understanding it.
It's so small as to be pointless to worry about it, but in theory at a certain point of the rounded corner it'll stop meeting the wood at an angle where it cuts and instead will be scraping. It's rather more of an issue with planing mouldings and the reason many wooden moulding planes tend to be "sprung" - to reduce the area of the moulding that's being scraped instead of cut. Maybe some nice person with a functioning woodworker's brain* knows of a handy diagram or summat somewhere?

Cheers, Alf

*Mine is currently in for reboot. :D
 
Many people have posted saying that they have a tiny camber, or they think (or hope) that the center of their blade is flat---they just nip off the corners. This suggests a method where you really wish your blade to be straight, but you need a little camber to prevent those nasty tracks from the corners.

But this type of camber is not going to help much with stock preparation as described in Charlesworth's DVDs. In that method, the whole point of the camber is that you can take a shaving that is markedly thicker on one side than the other. This gives a method for correcting an edge that is not square. But a teeny tiny camber won't do because it doesn't give a sufficiently uneven shaving---you'll plane your whole board away trying to get it square. If you want to work this way then you need the camber of 0.25 mm at the ends which in my experience is a pretty big camber, and it seems to require removing a significant amount of material. This amount of curvature could be larger than my microbevel, so I do not agree with the person who said the camber is applied "only during honing". I see this as part of the shaping of the edge. I find it takes an eternity to install such a camber with my 1000 grit stone. I go to coarser grits.

What is worse is that if you have a plane with a low bedding angle then the camber required to get the same cutting effect becomes much larger. So if you want to prepare a low angle plane with a 12 degree bed angle to cut equivalently you need a camber of 0.85 mm at the edges. I have used a powered grinder....

Regarding the shooting board, Charlesworth himself says that the 0.25 mm camber doesn't bother him with the shooting board. But as others have noted, if you're worried about it you can get a second blade for shooting. I personally never produced a square edge until I cambered my blade and used the Charlesworth method.
 
Rob,

Sorry to disagree, but out of square blades do not cause a crooked mouth.

Bench planes, BD, which have loads of lateral adjustment will tolerate significantly out of square blades.

best wishes,
David Charlesworth
 
David C":tillqf1u said:
Rob,

Sorry to disagree, but out of square blades do not cause a crooked mouth.

Agreed - it's out of plane bed that cause crooked mouths - esp on low bedding angle planes.

BugBear
 
The Jet jig is really for bigger cambers; grind straight and then put on the camber at the next stage. An easy way which gives repeatable results is to use a cambered "Odate" diamond stone (~600 grit) after grinding. The curvature is only about 2 or 3 thou. Unfortunately they've got expensive as pound is no longer worth the best part of two dollars.
 
ivan":37kc4tgv said:
The Jet jig is really for bigger cambers; grind straight and then put on the camber at the next stage. An easy way which gives repeatable results is to use a cambered "Odate" diamond stone (~600 grit) after grinding. The curvature is only about 2 or 3 thou. Unfortunately they've got expensive as pound is no longer worth the best part of two dollars.

Damn shame if you've got multiple width blades, or need different cambers for different purposes.

Could get a little expensive.

BugBear
 
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