Hand scraper geometry for brass

[AndySomogyi]

Any tips for hand scraper blade geometry for brass?

I laminated brass sheet to the back of my tapered gibs to build up size, and having a bear of time scraping it to match the stationary gib dovetail.

Standard carbide rake angle of 90° Just seems to mush the brass around. I really don’t have that much more to go, basically about 2-3 tenths and it’s there.

 

[Ulma Doctor]

good question.
although unorthodox sounding, Richard King had suggested using a 1/2 moon flaker blade in a discussion we had in class

 

[AndySomogyi]

good question.
although unorthodox sounding, Richard King had suggested using a 1/2 moon flaker blade in a discussion we had in class

Thanks, but I’m not sure what a flaker blade looks like. Does it have pos or negative rake?

 

[Braeden P]

sure hope the bluing is water soluble!

 

[francist]

I mucked around with this a while ago. HSS blade, 140 radius, standard 3 to 5 degree bevel on the edge. This is leaded brass (SAE360) and I found a low angle of attack produces better result. I have a fairly flexible shaft on the scraper as well and I think that is also of benefit. Easy to dig in though.

-frank

 

[homebrewed]

This is something I may end up doing as well. Watching.

I've scraped 6061 aluminum (mostly out of curiosity) and it worked OK with the same scrapers I use for steel.

 

[francist]

Ugh, I cannot imagine trying to scrape aluminum! Good on you for trying it

 

[AndySomogyi]

Ugh, I cannot imagine trying to scrape aluminum! Good on you for trying it

Aluminum scrapes super easy, I've experimented with it. Nice smooth chips, doesn't dig, and doesn't work harden.

 

[AndySomogyi]

I mucked around with this a while ago. HSS blade, 140 radius, standard 3 to 5 degree bevel on the edge. This is leaded brass (SAE360) and I found a low angle of attack produces better result. I have a fairly flexible shaft on the scraper as well and I think that is also of benefit. Easy to dig in though.

-frank
View attachment 360555View attachment 360556View attachment 360557

Thanks, I'll try lower angle, and make sure my scraper is really sharp.

 

[Ulma Doctor]

Thanks, but I’m not sure what a flaker blade looks like. Does it have pos or negative rake?

the flaker blade is #R60 through #R150
negative grind