You are attempting a most difficult drilling task! The bench drill
will not make it easier. If you don’t have a flex shaft or a micro
motor I would recommend a small hand drill. Hold the rod in a pin
vice or hand clamp. If using a hand drill then hold the rod in a
bench vice with wood jaws or clamp the pin vice in the bench vice.
The first step is to get the hole centered on the end of the rod. I
would use a small ball burr to get a depression because a centre
punch is tricky on such a small piece.
Start drilling and carefully observe the hole grow to the full
diameter of the drill bit. Tilt the drill slightly to correct any
wandering…if the hole appears to too close to the left edge then
tilt the drill to the left and the hole will creep to the right.
There is no ‘hole’ yet, just the drill bit getting to the full
diameter. You will see if it is centered easily as the hole grows
bigger, continually adjust the tilt as needed.
When the hole is centered start drilling down. Keep the drill bit
lined up with the silver rod as best you can, drill down 0.5mm, turn
the rod 90 degrees and repeat, always drilling all the way down from
the top each time. If using a hand drill with the rod in a vice then
you need to walk around the vice.
When you are 1mm deep you can see if the hole is following the
centre of the rod. It may help to remove the bit from the drill,
place it in the hole, and rotate rod and drill bit together so you
can see that they are lined up from all angles, but with practise
this can be done on the fly by feel and observation.
If the hole is leaning to one side, then re-drill from the top at
the correct angle, that is you must get the bottom of the hole back
to the centre of the rod before drilling any deeper.
Keep going like this 0.5mm at a time until you are half way through
Repeat all of the above from the other end.
When the two holes meet you will be able to see through the hole.
Small corrections can be made by gently drilling from the top at
each end to bring the two holes into line.
I could have said get a tube in the first place, but then you would
not have asked the question! With practise freehand drilling can be