Negative rake scraper angle for box making

[John Whitley]

I took one of Eric Lofstrom’s workshops last year, and scraper sharpening and raising a burr was a topic. He recommended (and handed out to us!) 1/8” Dremel tungsten carbide spiral bits turned upside down. The twist part just gets screwed into the top of your handle.

IIRC, Eric said that he liked the smaller diameter burnishing rod as he felt that made it easier to raise a good burr.

 

[Michael Perez]

I made a 10° tapered pin from some O1 tool steel for a guy at my club to try using as a Burnisher but he’s not reported back. I may have to make another to try myself. After turning and polishing the pin I hardened it but didn’t temper it, I left it “glass hard”. As such the Rockwell hardness should be slightly higher than HSS? The pin is 10mm diameter at the base.

I have the Ron Hock burnisher but is for card scrapers I’ll have to search if it’s carbide but it’s 3/8 thick
But now I’m using an End Mill that broke and it’s 1/8" thick the shaft and both are straight.

 

[Michael Perez]

I took one of Eric Lofstrom’s workshops last year, and scraper sharpening and raising a burr was a topic. He recommended (and handed out to us!) 1/8” Dremel tungsten carbide spiral bits turned upside down. The twist part just gets screwed into the top of your handle.

IIRC, Eric said that he liked the smaller diameter burnishing rod as he felt that made it easier to raise a good burr.

View attachment 66850

Thanks, mine is very similar but from end mill also carbide 1/16 the bit and the shank is 1/8 so I’ll also turned upside down but with ca glue.

 

[Michael Perez]

Thanks, mine is very similar but from end mill also carbide 1/16 the bit and the shank is 1/8 so I’ll also turned upside down but with ca glue.

You maybe are right about that but carbide mills or router bits usually have a polished shank verses the slightly rough surface on a carbide blank.
About 15 years ago I bought some scrap "up cut / down cut" CNC router bits that had been sharpened beyond their useful range for about $20.00 per pound. I have been using them ever since and they do not show any surface scratches.
View attachment 66831
The tool to the right of the burnisher is the only one with a negative rake grind and the only one that would be commonly used flat on the tool rest. The second and third from left work well in end grain vessels doing a shearing cut on rounded inside bottoms by rotating the tool off the flat but never flat. The use of the burr is dependant on the way you present the burr/cutting edge to the work. I recently made a video with my Iphone but I have not figured out how to make one of those recurring videos that are often seen on this forum.

Great tool collection! For every specific task the perfect tool.
Greetings

 

[Michael Perez]

Hello everyone,

I want to express my gratitude to all of you for your support and guidance as I continue learning, this time about scraper angles and carbide burnishers. I’m also really pleased with all the interaction and knowledge-sharing happening here.

Thanks again! As a final note, here are some pictures of my new tools—the scraper and burnisher. Now, I’m ready to dive into designing my boxes.

Happy turning!