Pure copper will roll tap fine. But copper is also abrasive and sticky so be careful and watch for the tap sticking in the copper after tapping a few holes. The copper may actually start to build up on the tap. Using a tapping fluid with sulfur will result in dark staining of the copper so you may want to avoid tapping fluids that use sulfur. Eric
I'm going to assume any ammonia type gun bore cleaner would be ok to clean copper off the tap.
What are favorite cutting fluids for use with copper? It seems to be the stickiest most awful stuff to work with.
I use cutting fluids and water soluble I buy in large quantities from industrial supply houses. You only need small amounts so I think you are best off using the clear thread cutting fluid from the hardware store. If it contains sulfur it doesn't have much and so will darken the copper slowly. So tap the hole and then clean the oil off. Some folks use whole milk to drill and tap copper. Really. Lard oil works well too but it is hard to find. I'm tempted to try some locally produced cream because it is just cream and even some of the "organic" cream has carrageenen in it. I think the butterfat in the heavy cream will be good for roll tapping. So next time I buy some to make caramel sauce I'll take a little over to the shop and see how well it works. Eric
good lube for copper is full fat milk
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