Tuesday, October 25, 2011

Coal Dust Punch Lubricant

This week I made some forming dies with the hydraulic forging press. The depressions were sunk in several heats with progressively larger top tool positive forms. Slight upsetting and entrapment of the pushing form is always a possibility and a problem if it occurs. I thought about how I sometimes use a pinch of coal dust in the hole when hot punching to prevent the punch from sticking and how sometimes dipping the punch in grease or Anti-seize also helps.

When I first was setting up the shop I needed a 55 gallon drum to build a small tumbler. I went to a local bakery, which gave me the drum, but it still had about 5 gallons of grease inside. They said it was edible grease - Linoleic acid - and was really high quality. I scraped it all out and filled a 5 gallon drum and filled several more clear plastic jars with it and have used it ever since for general lubrication.

I mixed some of the grease with some sifted coal dust about 50/50 and filled two small cans. It seemed to entirely prevent sticking as I worked with the press so I’ll continue using it. Apparently the escaping gases from the combusting grease prevent the punch from binding.

I looked up linoleic acid http://en.wikipedia.org/wiki/Linoleic_acid and found it is a colorless liquid at room temperature and what I scraped from the drum was a pale green soft solid so it must be mixed with something else. Any cooking grease or canola oil probably would work too. Use good ventilation. I have no idea what is in the fumes.


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