A Shop-Made Compact Rotary Broach

[Suzuki4evr]

I believe in going by color

By this,do you mean straw color I always read about when people reffur to when tempering? And now I am sorry if this looks like a stupid question, but is this meaning the actual color of brownish straw????

 

[woodchucker]

yes, it's a yellow brown

 

[7milesup]

And now I am sorry if this looks like a stupid question, but is this meaning the actual color of brownish straw????

My friend... there are no stupid questions on this forum. I(we) all are here to learn.

 

[Suzuki4evr]

My friend... there are no stupid questions on this forum. I(we) all are here to learn.

Thanks for the statement and I know this is true on this forum,but still somtimes you feel a bit stupid for asking you know.

 

[RJSakowski]

A yellowish brown is probably too dark for a cutting tool for steel. A barely perceptible color to a light straw color is probably more in line for a rotary broach. the steel should be polished to remove any color prior to tempering. View in a bright light. The color is due to surface oxidation of the steel. Different thicknesses of oxidation affect different wavelengths of light much like an oil film on water. If the process is too slow, a false reading may occur.

A Google searching for tempering colors will provide all the information you need.

 

[woodchucker]

A yellowish brown is probably too dark for a cutting tool for steel. A barely perceptible color to a light straw color is probably more in line for a rotary broach. the steel should be polished to remove any color prior to tempering. View in a bright light. The color is due to surface oxidation of the steel. Different thicknesses of oxidation affect different wavelengths of light much like an oil film on water. If the process is too slow, a false reading may occur.

A Google searching for tempering colors will provide all the information you need.

telling him what straw looks like by telling him a light straw, well.. that's like defining what a word is with the word.
it doesn't help.

 

[Suzuki4evr]

When tempering, do you need to quench again in oil or leave to cool on its own?

 

[woodchucker]

When tempering, do you need to quench again in oil or leave to cool on its own?

Let it cool on it's own

 

[woodchucker]

notice that color charts represent things differently.

 

[pontiac428]

Color correlates with temperature. What color depends on the steel and the purpose. Check the data books and handbooks for the type of steel you are using and the hardness you want, and go from there. You can get well into the golden brown range on a hot plate.