Hi everyone. quick question, as i've been practicing and expanding (without new tools) i have come across the need to make more of my own tools and since i don't know much about the differences between punches, hot cutters, and chisels i was wondering what seperates the metals in each and if the methods behind making each of them differ. any input is greatly appreciated. =)

Generally an edge designed for hot cutting will be a more slender taper and a more acute angle grind than an edge designed for cold cutting. More subtly most hot cut edges will have a curve that functions to limit the length of edge that is exposed to heat at any given moment and also delivers more cutting force to a small area in use. Cold cutters actually benefit from the second advantage above and work well with a curved edge too, but are less commonly made that way. To a certain degree either type of cutter can be used in limited applications for either type of cutting. Heavy use of a hot cutter on cold work is likely to damage it some though and a cold cutter does inferior work when used on hot metal.
This thread has a most AWESOME discussion in incredible detail on the shaping of slitters and other punches.

slitter geometry

If you will use the search function on this page to search for "slitter geometry" you will get several other useful threads also.

Generally an edge designed for hot cutting will be a more slender taper and a more acute angle grind than an edge designed for cold cutting. More subtly most hot cut edges will have a curve that functions to limit the length of edge that is exposed to heat at any given moment and also delivers more cutting force to a small area in use. Cold cutters actually benefit from the second advantage above and work well with a curved edge too, but are less commonly made that way. To a certain degree either type of cutter can be used in limited applications for either type of cutting. Heavy use of a hot cutter on cold work is likely to damage it some though and a cold cutter does inferior work when used on hot metal.
This thread has a most AWESOME discussion in incredible detail on the shaping of slitters and other punches.

slitter geometry

If you will use the search function on this page to search for "slitter geometry" you will get several other useful threads also.

I agree with all said, and would just like to expand a couple of points re cold chisels,

Use a cold chisel on hot steel and it will remove the tempering from the edges and should be re heat treated if they have been used on red hot metal.

The curved end on a cold chisel enables the user to mark out or cut out curves in plate easily leaving a 'smooth' line/edge

Cold chisels to be used on mild steel have a 60º included angle. Hot chisels have a 20º to 40º included angle.

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