Tracy’s tip this week was different ways to drill a hole in a blank to show the maximum depth for hollowing. There are many ways that can be used to achieve the end result, some of which can be quite dangerous.
One of the safest and quickest ways of drilling the hole to show the maximum depth, is to make one of the tools shown below.
The tool is quite easy to make. The only parts that are needed are an SDS keyless drill chuck and a wooden handle that can be turned to your own design. This is an example of an SDS chuck and shows a groove in the shaft, which helps the grip when the chuck is bonded into the shaft.
When the tool has been constructed, you will find it quite easy to use, there are a couple of points to remember:-
When entering the drill bit into the work, ensure it’s on center or the tool will be pulled side ways.
Don’t attempt to drill the hole in one go as the drill bit will tend to bind and jam. Drill a little at a time and clear the flute.
Set th lathe speed as low as possible.
This is a rough sketch of the tools handle. Drill the larger hole first and the second hole to suit the chucks shaft size. 
The handle can be shaped to your own design but ensure it will allow a good grip when in use.
I hope you find this information useful.
Alan