Best inserts for finishing gummy 1018?

[Toolguy]

For those wanting a HSS type cutting tool that holds an edge longer, try Tantung. One note of caution, when grinding, don't quench at all, only air cool. This is one of the things they used before carbide was widely available.

[Axkiker]

For those wanting a HSS type cutting tool that holds an edge longer, try Tantung. One note of caution, when grinding, don't quench at all, only air cool. This is one of the things they used before carbide was widely available.

Never heard of this stuff before but based on the description I found seems promising. Does it require special grinding wheels to sharpen?

Tantung Description

Can be used on machines where speeds and rigidity are limited. With tantung tools, older machines can handle increased production loads and help reduce costs. Performs interrupted cuts significantly better than carbides.

[MattiJ]

Never heard of this stuff before but based on the description I found seems promising. Does it require special grinding wheels to sharpen?

Tantung Description

Can be used on machines where speeds and rigidity are limited. With tantung tools, older machines can handle increased production loads and help reduce costs. Performs interrupted cuts significantly better than carbides.

Afaik can be sharpened just like HSS but just takes more time. And maybe you could also use diamond wheels since it doesn't contain iron like HSS. "Only" problem is very limited availability and high price. I belive in europe these alloys are more commonly referred as "stellite"

http://conradhoffman.com/stellite.htm

[J Tiers]

Hah........... nice, thank you.

I may have some of the notched cutters, so I will be checking with my pocket magnet, you bet...!

[MattiJ]

So I decided to head in to the "you must be full-of-sh*t tenths category" and see what is the minimum DOC I can get.
0,001 mm digital dial gauge set to cross slide and afterwards measured with 0,001mm digi-mike:

DOC measured with the dial gauge:
0,010 mm DOC, actual diameter from 14,717 to 14,700
0,005 mm DOC, actual diameter from 14,701 to 14,695 (still cutting actual chips, albeit almost invisible)

Looks like there is 0,003 to 0,004 mm error on measured diameter vs. measured DOC. Or abouts one and half "tenths"
Or it could be measurement errors piling up.

[Jaakko Fagerlund]

So I decided to head in to the "you must be full-of-sh*t tenths category" and see what is the minimum DOC I can get.
0,001 mm digital dial gauge set to cross slide and afterwards measured with 0,001mm digi-mike:

DOC measured with the dial gauge:
0,010 mm DOC, actual diameter from 14,717 to 14,700
0,005 mm DOC, actual diameter from 14,701 to 14,695 (still cutting actual chips, albeit almost invisible)

Looks like there is 0,003 to 0,004 mm error on measured diameter vs. measured DOC. Or abouts one and half "tenths"
Or it could be measurement errors piling up.

Whatever the actual measurements, you can positively say that it can take less than you need

[dian]

not clear what you were doing. carbide or hss? what geometry? you know, you can get the diameter down without cutting. the tool just burnishes the work.

[MattiJ]

not clear what you were doing. carbide or hss? what geometry? you know, you can get the diameter down without cutting. the tool just burnishes the work.

Same Kennametal KY1615 ceramic insert sharpened with 0 degree relief and 7 degree rake angle, both surfaces now lapped close to mirror polish with 600grit +5 + 1 micron diamond lapping compoud.

[mattthemuppet]

I ground a threading tool out of Stellite. Only a 1/4in bit but holy cow it took a long time. I wish I had had a coarser wheel than the 100grit white wheel on my grinder.

[lalatheman]

Same Kennametal KY1615 ceramic insert sharpened with 0 degree relief and 7 degree rake angle, both surfaces now lapped close to mirror polish with 600grit +5 + 1 micron diamond lapping compoud.

Did you round or break the edge , where the two highly polished surfaces come together ?

Thanks
Dave Lawrence