Image of burred iron for scraper plane

[patrickjchase]

Tangential to the scraper plane thread, attached is an image of the burr at the edge of a scraper blade iron. The iron has a 45 deg bevel and was burred with the burnisher held ~15 deg below horizontal (~30 deg above the bevel).

I created the image by notching a sawtooth into the iron's edge with a needle file and then wasting the metal between the tooth's vertical face and the edge of the iron to expose it. Each pixel in the image is 1.3 microns.

As I've said in the other thread, the resulting profile (and cutting mechanics) are similar to a plane with a tightly-set cap iron.

 

[MusicMan]

Nice one!

 

[Rorschach]

I can't work out what I am seeing lol.

 

[AndyT]

Nice photo of what used to have to be shown as a diagram, eg in "Woodwork Tools" by JC Brough, about 1920.

 

[MusicMan]

Furthermore, this picture does seem to show that the idea of altering the angle of the burr with the point of a tapered burnisher is nonsense (see the current thread on scraper planes). That idea seems to assume that the burr is a flap that is hinged at the edge. The image shows clearly that it is not, but is a progressive hook.

The way to sharpen them is clearly with the burnisher working at progressively greater angles. Funnily enough, this is what Stanley specified in their original manual ....

 

[Rorschach]

Nice photo of what used to have to be shown as a diagram, eg in "Woodwork Tools" by JC Brough, about 1920.

Ahh now I see it.

 

[David C]

Excellent photo.

David

 

[Trafalgar]

Tangential to the scraper plane thread, attached is an image of the burr at the edge of a scraper blade iron. The iron has a 45 deg bevel and was burred with the burnisher held ~15 deg below horizontal (~30 deg above the bevel).



I created the image by notching a sawtooth into the iron's edge with a needle file and then wasting the metal between the tooth's vertical face and the edge of the iron to expose it. Each pixel in the image is 1.3 microns.

As I've said in the other thread, the resulting profile (and cutting mechanics) are similar to a plane with a tightly-set cap iron.

Textbook!

 

[bugbear]

I've added a little scale bar to Patrick's excellent photo, based on a 1.3 micron pixel (so 384 pixels = 0.5mm)

BugBear

 

[patrickjchase]

I've added a little scale bar to Patrick's excellent photo, based on a 1.3 micron pixel (so 384 pixels = 0.5mm)

Yes, the scale is correct.

The picture I posted is a crop from a 5:1 image taken with a Canon MP-E 65 lens and Canon 1Dx II body. The 36 x 24 mm sensor captured a 7.2 x 4.8 mm area. I focussed with a macro rail and lit with a lens-mounted closeup flash.

 

[swagman]

I created the image by notching a sawtooth into the iron's edge with a needle file and then wasting the metal between the tooth's vertical face and the edge of the iron to expose it.

Patrick; is there a chance you could provide a similar photo without the latter intervention. It would provide a clearer indication of what the turned hook looks like prior to use.

regards Stewie;

 

[patrickjchase]

I created the image by notching a sawtooth into the iron's edge with a needle file and then wasting the metal between the tooth's vertical face and the edge of the iron to expose it.

Patrick; is there a chance you could provide a similar photo without the latter intervention. It would provide a clearer indication of what the turned hook looks like prior to use.

regards Stewie;

Not with my equipment. You could probably get a usable oblique shot with an SEM since those aren't limited by diffraction the way an optical camera is, but I don't have one laying around.

Being explicit, the reason for notching the face like that was to expose a perpendicular non-corner section for a head-on shot. I only had 0.002" of focus depth to work with, so even that was a big challenging to set up. I mounted the camera+lens to a lead-screw-driven stage, which is a fairly common trick in "serious" macrophotography.