Jig for Drilling a Long Hole through a Dowel
- by Greg Alvey
I have just started on a new project to be built inside a very challenging bottle. The bottle I have chosen is round with a 13 inch long neck. I will be using a trick stopper, that is, one with a wooden piece going through the stopper inside the bottle making it impossible to remove. Allowing room for the crosspiece inside the bottle, the stopper will need to be at least 14 inches long with a hole drilled through the center the whole length. The length required is way beyond the capacities of my drill press and there is no way I can hand-hold the stock with any degree of accuracy.
I found a simple solution that works great using a handheld corded or cordless drill that is clamped to a wooden base. The hole for this project is 1/8” diameter, but sometimes I use ranges from 1/16”, 1/8” to 3/16” diameters from to 10 – 16 inches in length.
The drill bits I needed were bought at Menards but can also be found at Lowes or Home Depot or the Internet. I bought both a 6 inch bit and a twelve inch bit in each diameter. It is very important that the bit is straight without a bow or curve so that it drills true. This is usually not a problem with the 6 inch size but is a very common problem in a 12 inch length. I had to make three store exchanges before I found the right bit.
The jig setup is temporary and easy to set up and take down. I started with a piece of plywood approximately 16 inches by 30 inches that I had laying around for the base but that size is random and bigger than actually required so just choose a size that meets your needs. I clamped it to a 2 foot by 4 foot portable table.
For this project I turned a cordless drill upside down and clamped to the plywood with 2” x 2” x 8" length blocks on each side for stability. These blocks are then clamped to the table. Check the level from all directions and make adjustments where necessary. Notice that the clamps are positioned not only for good stability but also to allow changing the drill battery should this be necessary without have to disassemble the setup.
It is important to use a channel to guide the dowel you are drilling. This can be made by cutting a “v” in a length of wood on the table saw, or by other similar approaches. I happen to have an extra length of a bullnose or stair nose stock left over from a hardwood flooring project. The bullnose had been used to finish the wood where it joined the stairs. I screwed the bullnose upside down to a 6" x ¾” board approximately 2' long board. I then clamped the 6" board to the plywood to raise the stock to the required height in relation to the drill bit. I had to use some small shims to level the board to be sure it was exactly parallel with the drill bit. I also had to make some minor adjustment with the clamps holding the board to be perfectly aligned.
I am now ready to drill a 1/8” hole through a dowel 14 inches in length. First, I determined the center point on both ends of the dowel. I started drilling using a regular 1/8” drill bit approximately about 3 inches long to get the hole started. That done, I changed to the six inch long drill bit, taking my time to avoid getting off track. Once I reached the end of the 6 inch bit I changed over to the 12" bit. Be sure to recheck level to ensure you are still parallel with the bit and stock. Take your time and be sure to back out often to clear away the sawdust. You may find it advantageous or even necessary, depending on the length of the dowel, to drill from each end of the dowel with plans to meet in the center.
I tried a couple of times using a smaller 1/16” bit with plans to switch to a 1/8” bit to enlarge the hole thinking this would make it easier. This proved to be a bad idea and when I switched to the 1/8" bit it exited through the side of the dowel before getting to the end. I recommend starting and finishing with the actual diameter you plan to drill.
If using a cordless drill you should ideally have someone available to turn the drill on/off as needed. My wife was a great assistant for this process. But if you need to work alone I recommend you use a corded drill and purchase a foot treadle similar to one used with a sewing machine. You use the treadle by plugging the power tool into the heel of the treadle and then plug the treadle into an electrical outlet. The tool must be held in an "On" position. I used a simple clamp to hold the drill trigger in. I purchased my treadle - MLCS 9080 Billy Pedal Foot Switch, Deadman Style - through Amazon for $22.95 but there are several options for cheaper treadles that would likely work just fine. The treadle accommodates a three-prong plugin and can be used with most power tools for other projects.
The following is from an earlier project also requiring a long dowel with a a trick stopper: