View Full Version : Machining Zinc?

04-05-2011, 05:56 PM
My brother-in-law would like some light machining done on a zinc model railroading casting. Any tricks to it? Any toxicity concerns?


- T

Dr Stan
04-05-2011, 07:25 PM
I would not grind or sand it as the power is pretty nasty (toxic). Depending on the composition of the alloy it could be from easy to absolutely a PITA to machine. If it is 100% zinc its gummy and will like to build up on your cutting tools. I know as I machined sacrificial zinc anodes when I was in the Navy to reduce salt water corrosion in some tanks. If it has a fair amount of aluminum in the mix it will machine much like aluminum.

Hope this helps.

04-05-2011, 07:40 PM
Its probably not pure zinc but Zamac.

04-05-2011, 08:57 PM
Yep. probably Zamac. It machines nicely but it gets hot and it can dig in suddenly if the setup isn't really secure. When that happens it usually destroys the part.

04-06-2011, 12:10 PM
Is it possible to machine zinc coated pieces without cashing peeling/fractures in the zinc coating? I know this doesn't work on chrome plated pieces. I don't have any such project, just wondering...

04-06-2011, 02:23 PM
Zinc machines a lot like brass you need a razor shape end mill. I use to machine a lot of prototype parts at work. We bought zinc in bars and melted them down then I hand poured the liquid zinc into small hand made molds that cast the zinc into blocks about 1/4" wider, 1/4" longer and about 1/2" thicker than the finished part. A dull cutter will produce a lot of heat. Zinc must be abrasive because a brand new end mill will work fine for several days then it starts getting hot. It was always best for me to use water cooling for a day then swap to another razor sharp end mill. The end mill that I removed would still cut steel fine.

04-06-2011, 02:34 PM
Very sharp edge tool will be needed and probably a negative rake and/or clearance needed to help stop it from digging in. Try with something you dont care about first.