Yes, beef fat is commonly used, but it's not what you cut off a steak.

Use "tallow" mixed with powdered graphite.  I quickly heat some up in
a 35 mm film canister in the microwave, then mix in some graphite.
It hardens like candle wax. You can rub it on the parts or re-melt and
brush on.

I bought my tallow from Organ Supply Industries, P.O. Box 8325, Erie,
PA 16505.  Email <osi@organsuply.com>.

Philip Jamison
West Chester, PA