How do I put a really long narrow straight hole in a piece of wood?

Question

I tried using a really long thin drill bit that probably had a different purpose (like maybe drywall stuff) to put a hole in a tobacco pipe project. But the bit blew out the side of the wood because it didn't drill straight.

This pipe is about 20 inches long, and I need to drill about 16 of that.

How do I put a really long narrow straight hole in a piece of wood?

Answer 1

You can do it without using a drill.

See how pencils are made

• cut some square stock to length
• saw it in half lengthways
• cut a groove in each half
• glue the halves together
• shape the outside (e.g. using a spokeshave and dowel plate)

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There's a useful video of using a drill to make a hole in dowel. In summary the technique shown is

• start with well oversize dowel
• use a variety of drill bit lengths starting with the shortest
• drill very slowly, a quarter-inch at a time.
• use a spirit-level on the drill
• shape the dowel after drilling to take into account
  • the direction of the hole (which won't emerge at centre)
  • the curvature of the hole (ruling out using a lathe)

Answer 2

I don't think a hole this long is possible with any conventional drill bit, and finding a suitable one of this length which would be difficult to say the least. And anyway there is a significant problem with drift or wander, particularly when drilling into end grain as you might be here. Note: this is even if the drilling is done on a drill press, the amount of wander can be quite amazing.

Even in the past when very long drill bits were more commonly seen as part of the woodworking tool kit (either augers to be turned directly with a wooden handle, or for use with a brace) once you got to very long lengths in relation to the diameter of the hole it was common to use specialist bits made for that purpose only, for example shell bits.

Here's a modern shell auger to give an idea of what the traditional style looks like:

I suspect the only way you'll achieve this length of hole is if you can find a suitable shell auger bit or are willing to go to the trouble of making your own. You'd start the hole with a normal bit or matching diameter, then slip the shell bit into the hole and continue from there.

Answer 3

But the bit blew out the side of the wood because it didn't drill straight.

I think you already identified your problem. When you start doing things where small misalignments can lead to large issues, setup is key.

I've made a couple pipes before, though the draft hole was only about 3" long. Even that took a large amount of measuring and tweaking to get the bit to exactly where I needed it and to drill straight.

This pipe is about 20 inches long, and I need to drill about 16 of that.

I won't lie, what you're trying to do is very difficult. Your pipe stem is likely thin to begin with, so you have very little margin for error in the setup of your drill bit. The only advise I can give is to check, re-check, and re-re-check your alignment before drilling and hope that the bit doesn't wander through the cut.

Answer 4

I'm facing a related issue, though not to tolerances so fine as you face.

In the course of my researches, I learnt how boat builders stay true while drilling a hole for a propeller drive shaft several metres through the keelboard.

They don't move the drill, they move the job using a jig similar to a saw table fence. But instead of a circular saw blade there is a spinning auger perfectly parallel to both fence and table.

Build yourself a jig like this and you will be able to turn out Gandalf pipes by the dozen.

Answer 5

You need a "gun" drill, it cuts on one side . It would costly for making a pipe. Cost not a problem when you are drilling several expensive gun barrels.