Toad Hall's rudder tube runs up at an angle from below the counter stern to the deck. I had installed the tube itself when I built the Central Girder and that was fine. But when I put the king plank down and epoxied it to the sub-deck I forgot to mark the location of the tube at the deck surface and the king plank completely obscured the position. I didn't want to spoil my king plank by guessing at the location. I knew that if I had a long enough drill bit I could just insert it into the tube from below and drill a small hole through the king plank which could then be enlarged quite easily.

Electricians use long flexible drill bits to get through rafters when running wiring, and my friend (who is an electrician) has a couple of these. But I wanted to drill the hole NOW!

Here's what I did.

The distance from the bottom of the hull to the top of the deck measured out to 27". I have a couple of long bits but they were not long enough to reach this. I didn't want to fiddle around making up some extension either. I did however have some 3/8" threaded rod that I found behind a business one day and put away until I needed it.

I never throw anything away, remember?

I ground a simple "bit" on the end of the threaded rod which measured about 36" in total length. The profile is as shown. Note that I ground the bit so that it had a flat on the tip rather than a point. In this configuration it scraped the wood to penetrate it. Since it is not possible to grind a true twist into the end with a simple grinder, it is important that you (if you try this at home) grind a profile which will quickly "scrape" away material in order to penetrate it.

It didn't have to be very precise because I was only trying to get through about 5/16" of material in the king plank.

I chucked it in my right-angle drill, pushed it up the rudder tube until it contacted the bottom of the king plank and pressed the button. With a little push the drill entered into the wood and to my surprise, climbed right through in double-quick time with no effort. In fact, I could not remove the "bit" without switching the drill to reverse and backing it out!

What had happened was that the point of the "bit", being smaller than the outside diameter of the rod, had allowed the threads of the rod to bite into the wood and pull the bit right through. It made drilling very easy.

If you ever have need of a long bit, use a bit of threaded rod like I did; it will make the job easier.