Colorado Model Engineering Society


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Removing a broken drill or tap in
nonferrus metals (brass - aluminum, etc.)



At most any grocery store, buy a box of alum. Select a glass or ceramic container (made for stove top use) or an aluminum pot large enough to place your part in so it can be submerged in water. Remove the part and bring the water up to just below the boiling point of the water. Add alum until no more will disolve, then place your part in the solution. Keep the solution at a simmer and you will soon observe a trail of tiny bubbles coming from the broken drill/tap. Keep the solution at a simmer and add water as needed as long as the trail of bubbles continue. When the bubbles stop, remove the part and let cool for inspection. You should discover that the steel drill or tap has turned to a rusty mud which is easily removed from the hole.


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