Drilling holes in HHS

You can anneal (soften) the portion to be drilled by heating it red hot (cherry red) and permitting it to slowly cool. It is important that the working end of the tool be protected from the heat by use of a heat sink, or the tempering (hardening) will be affected.

I fasten a couple pairs of vise grips just below the area to be annealed and the area to be protected as a heat sink. In addition, wet rags wrapped below the vise grips help to absorb heat as well.

Once the HSS is annealed, it will readily accept drilling and shaping.

Tim

Tom Thorsen wrote:

You can spot anneal it by putting a nail in a drill press and running it at a medium speed. Just maintain a steady pressure with the nail on the HSS until the HSS gets red hot.

You can also drill it with a carbide drill bit, masonary bit, or carbide end mill.

Grinding a hole with a Dremel type tool also works.

HSS is valuable because it has what is called "red hardness". You can run it at a red heat in metalworking without it losing its edge. You won't find it very easy to anneal.

Grind it, or find a machine shop with an EDM machine,

John Martin

Bill:

You did not offend. I want to add a wooden handle to increase the length and the leverage associated with the tool. It is a matter of adding finesse to an already fine tool. The problem with the tool is that you can often end up with a leverage ratio of 1:1 and this makes it harder to control (grabby). The grind and tool position are correct and I do not really want to "waste off" 1/2" making boxes and other items in fine woods where I am really concerned about maintaining grain continuity.

From a recent class with Stuart Batty, he drilled into us the need to maintain the minimum ratios for cutting and scraping tools for fine tool control. I wish I could take credit for this idea but it is his. I have make several adjustments in the way some of my tools are ground and how I approach a cut depending on what I want to achieve and they are because of his insight.

HI, To penetrate the HSS, you need to soften the steel, or use a tool harder than it is. In practical terms, that leaves you with either carbide or diamond drills or burrs. (Titanium Nitride is a possibility, depending on the hardness of the HSS.) You can use a diamond burr in a Dremel at low speed to open up a hole and go to a larger cylindrical burr to enlarger it to you desired size. You can cool with water as you cut.

Ken Moon Webberville, TX

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You could try a solid cobalt drill ( these are available at any industrial supplier. I have drilled holes in 1/8" stellite using carbide tipped masonary drills at a slow speed with good tapping fluid and lots of pressure.

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