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Machining titanium on the mini-lathe in the home metalworking workshop

Some time ago I picked up a small billet of titanium on ebay. This rough unfinished billet has sat on top of my desk looking at me ever since. I've not done a thing with it. The main use has been handing it to people and asking what it is. People are suprised to learn it is titanium - it is not a metal that people are familiar with, like aluminium or steel, and it is thought of as rather exotic. Uou tell poeple that over one hundred tonnes of titanium goes into making an airliner, and they are impressed!

The other day I decided to pull my finger out and clean up the titanium billet into a nicely finished billet. It doesn't serve much use, aside from an extra-thick drinks mat for extremely hot and heavy drinks, but it looks much nicer. I suppose I could slice it up and make 3 normal drinks mats, but that is a lot of hard work.

I like to think of titanium as being about as light as aluminium, and about as hard and strong as steel. It is also more expensive than both put together!

Here are some photos and comments on tidying up this simple titanium billet on the mini-lathe.

I purchased this billet of titanium from Ebay for a few pounds. It is approximately 90mm by 25mm.

The first task of cleaning up this billet of titanium on the mini-lathe is to use the 4 jaw chuck and indicator to adjust the jaws on the titanium billet so that it is turning concentric to the rotational axis of the lathe. This means that I will only have to remove the minimum amount of material to get a smooth finished lump of titanium.

Here I am using an indexable tool to turn the outside of the titanium billet. Obviously the jaws of the 4 jaw chuck prevent me turning the quarter inch or so. It is important to give the chuck jaws a wide berth.

Without removing the titanium billet from the chuck of the mini-lathe, I move onto facing the front face of the billet. Tool height is important here to avoid a "nipple" of uncut metal in the centre. A 3.5inch diameter titanium billet is a "long" facing cut, so I attach the power drill to the cross slide and use the power screwdriver setting to drive the cutting tool back and forth over the face. This saves a lot of aching fingers.

Now we remove the half finished part from the chuck and swap it around. It is important to use the dial indicator on the finished surface to make sure it is properly centered in the lathe. Then we can proceed with facing and turning up the unfinished end of the titanium billet.

Here we see the partly faced end of the titanium billet. You can see some of the surface is nicely smoothed, but there are still some rough areas, so we need to face off a bit more of the surface. Making sure you've got the part properly centered at the beginning reduces the amount of cutting you need to do.

Here I use a small ground patch on the end of some HSS tool steel to bevel the edge of the titanium - the action of facing after turning raises a small burr, and it is much nicer to have a bevelled edge rather than a sharp corner.

Finally make sure all sign of a burr is removed with a light touch of the diamond file.

Here is the finished nice and clean billet of titanium. I was actually impressed at how easy it was to cut the titanium. I expected it to be a nightmere to machine, but in reality it was easier than steel. There is a huge amount of heat generated by even the lightest of cuts - thick white smoke was quickly aparent. I was terrified of setting fire to the titanium, so I tried using oil as a lubricant, but this didn't seem to help much. I also tried using 3 in one silicone spray lubricant, and this seemed to help a great deal and removed the smoking almost entirely. Like all hard metals, slowly but surely is the way to go.