Make lathe gears easily

Page 2

Suitable metals

There are three basic types of metal suitable for making gears on a small or medium lathe.


Easy to work, and hardens with use.  Red brass is the best grade.

Expensive to buy and mainly available through merchants.

Can be difficult to obtain in larger sizes.

Hard aluminium

This is extensively used for timing gears in car engines and is very durable and quiet running.

Machine grade 2011 is the one to use. 

A good substitute is melted down scrap alloy car wheel rims, which can cost nothing off of Craig's list or Gumtree.  Any non bending aluminium will be quite OK to use.

You can easily make your own round stock.  It's not difficult to melt down scrap aluminum in a simple brick hearth, using wood or charcoal for fuel, and a hair dryer or vacuum cleaner with a metal extension tube for a bellows.

After removing the dross (oxide rubbish) from the surface of the melt, pour the alloy into a tin can larger in diameter than the gear to be made, and let it harden.

The aluminium will shrink away from the can, which can then be easily removed with snips and pliers, leaving a rough metal slug.

cast gear blank

It looks a bit ugly but beneath that surface lies a nice piece of alloy.

Turn the slug down to work dimensions and you're set to go.

aluminum gear blank

An excellent hard aluminum blank with zero defects seen emerging from the slug above.  You wouldn't buy better, and it cost nothing.

A damaged cast iron gear and the home made aluminum stock from which the new gear will be machined. 

aluminum gear blank

The great thing about this is that you can easily re-melt any failed gears and try again.  So no worries about cost blowing out while you experiment.

Here's a video showing how a gear blank is machined from the rough alloy casting.

And here's a video explaining which type of scrap aluminium to use.

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