I already showed my side drilling system on the lathe :
Homemade Transverse Drilling Attachment
This first version has the drawback of having a too big chuck and too long attachment sleeve behind it so that it really works only with short bits.
I recently found a new kind of smaller chuck and imagined a way to attach it at the end of a shaft with the bare minimum additional pieces.
Here is how I did it :
The mandrel is a small three jaws mandrel to be used on a power screw driver. It is quite precisely made.
It has an Hex shaft. Here is how I imagined attaching it at the end of my 12 mm shaft. I simply drilled a side hole in the 12 mm shaft like if I wanted to use a set screw.
But instead of using a set screw, I just filled the hole (two sides) by welding a little spot.
In order to avoid any projections, I wrapped the chuck and shaft with a piece of aluminum sheet.
I then cleaned up the welded joint on the lathe to get a smooth surface on the shaft.
Here this is the little fixture I use on the metal lathe QCTP. You can see that the chuck can be pulled back
much more than on the previous version.
And here on the wood lathe :