In Googling "drill bit guide" came across this and other tools like it:
Something like this seems perfect for being able to drill a straight hole through wood. However, I can't seem to find anything like it at Lowe's, Home Depot, or Menard's. Surely, I must not be searching properly as it would appear that such a tool would be a very handy addition to one's arsenal of precision tools.
What, exactly, is the industry term for such a tool that makes for the easy centering of a drill bit?
Update 5/12/2013
While my jig below does work, this product is even better!
Big Gator Tools V-DrillGuide Standard Size Portable Drilling Guide
Original Answer
I am answering my own question here with an awesome, home-grown solution to my problem. I fastened two pieces of wood together at a 90 degree angle. Corner clamps made it easy to get it perfect. I then took a third piece of wood and cut a 45 degree bevel off the corner. This piece is my drill bit adapter that fits a number of larger-sized drill bits, but was made with my 3/8" bit in mind. I also made another for smaller sizes (not shown).
To hold the adapter firmly in place and tight against the bit, I use one of my smaller c-clamps. Using this custom guide, I was able to drill a near-perfect hole into the subject. I also used another similar custom assembly that works with a plug cutter bit for my power drill.
No expensive equipment required!
Amazon carries a drill guide that looks almost the same as the one you found. The manufacturer brand is WoodRiver.
In my quest to the perfectly perpendicular and/or perfectly placed hole, I have tried multiple solutions but the truth is, for truly, 100% accuracy you need: A high-quality drill press with a chuck that is made to tight specifications. Then, you need to calibrate it with a special dial indicator (even drill presses drill inaccurate holes out of the box). Must calibrate the table left-to-right and in many cases the front-to-back needs some work as well. It is the only way to make a hole truly perpendicular to the face of the piece you are working on.
Then, no standard drill bit will work on metal (for wood this is not as critical) without a bit of wandering: they usually deflect a bit and "walk" slightly to one side before penetrating the material. This is more so in hard metal than on soft alloys but it happens almost all the time, even if you start with a smaller bit and enlarge the hole with subsequent passes with larger bits.
To solve this you need a "Center Drill". This are very short and hard bits made specifically for this purpose. You use them to drill a tine hole, always smaller than the final hole you need but it will give your final-size bit a depression where it will start to drill WITHOUT deflecting.
Now, this level of accuracy is only needed is some situations but the point of this post was to pass some info I have gathered by researching the subject in depth and then my own trial-and-error not to mention a lot of cash spend on tools. I can say after all this money and time spent I can make a hole in almost any material right where I want it, less than a thousand of an inch off, without breaking any drill bits.
To top it off, you cannot make a perfectly round hole with a drill bit, if you want to take it to the extreme, you need to finish with a drill bit slightly smaller than the true hole size you want and then use a reamer (again, mostly for metal drilling and more pronounced with the larger bits).
I understand this is taking it into the machinist territory but I am not a machinist and enjoy seeing how accurate I can be in my work/hobbies, sometimes well beyond what is needed, just to see how far I can go.
Harbor frieght has this http://www.harborfreight.com/angle-drill-guide-95622.html. Reviews are mixed about its usefullness. Set up does seem more involved than the unit you are looking at,but may be more versitile.
This guy had a really good idea for a DIY drill guide, using mirrors to keep your drill bit aligned. Looks like it might work better than any of the drill guides shown here.
I have been looking to do this myself and am trying to drill a hole into a pool ball without a drill press (I know, what an idiot)
I was almost going to give up until I got some clues on this page.
Grab a piece of wood which is about 1 cm thick and drill a hole in it the same size as the drill bit you are going to use to drill through the final object. Then, put both in a vice with support so they line up perfectly. You can then use the drill piece of wood as a guide to ensure the whole is roughly central.
Of course, this isn't going to come close to using a drill press but it's a starter for 10 and should stop me drilling through my knee-cap as I slip off the pool ball.
Take a 3x3 block of wood thats 1/2 inch thick and drill a hole in it. There's your guide.
Drill a larger hole into a base board and set the ball in the hole. It'll hold the ball steady. You may want to make a pilot hole or dimple in the ball but you could also sand a wee bit of a flat spot on the ball as long as you know the hole you ultimately drill will eat up the entire flat spot. You could also use painter's tape to steady the drill tip against the smooth surface of the ball and possibly even around the diameter of the ball in the "cradle" hole to both keep it from sliding and to use as an eyeball gauge to keep the ball upright. Good luck!
