When it comes to working in the shop, I am not a die hard fan of any one method for every application. For example, it is easy enough to do all my drilling for a seat with just a battery powered hand drill. But I have been known to use my drill press and an adjustable angle jig to drill critical spindle holes for referencing an arm bow for a continuous arm chair. On the other hand, I drill many holes with a bit and brace. For instance the leg holes and the arm post holes. I love the set up that I starting use for this that I will show below. I have learned that really as much as I like the hard work in making things with muscle power, I am lazy. I mean, as long as I am not compromising quality, I will take the easiest route to complete a task. As much as I admire the set ups used by Pete Galbert, like his mirror and bevel gage combination, which work super accurately, I tend to just grab my tools and start going at it. I dislike setting up things. So when I got this extension for my bit brace I suddenly knew I was going to be drilling differently.
This extension allows me to set my angle gage, place it next to my sighting line and not have to move it while drilling or looking over at it from the side to see if it lines up. Look at how I sight up to drill in the next two photos.
Above, I just keep the shaft of my extension in line with the gage and it is dead on. Since I am so far above it that is easy to do and of course it is nice and close to the drill shaft which is usually not a possibility. An added advantage is that the additional length on both the gage and the drill add to the accuracy, where as, the shorter angle gages and drill bits don't show discrepancy between the two as dramatically.
Here I am looking down the sighting line in order to keep it 90˚ to my resultant angle. (Not sure if that is technically the accurate way to say it but you get my drift) This again works well because of the long shaft. Aiming this is a bit different than the other angle but does well once you get the sense of it. Just keep the shaft pointing down the line. It will be dead on as long as you are aiming while the square is on the line as well.
Below, the results speak for themselves. Here is an arm post hole, with a dummy place in the hole for reference, that was drilled and you can see it is dead on in both planes. The nice thing really is that you can drill all in one go without stopping. No stopping and checking your progress or worse yet asking someone to watch you as you drill to keep you in line.
As a note, the seat blank is set up about 11" off the floor while drilling. I have a cross bar on my bench at that height to support one end and a stool for the other. A clamp keeps everything from shifting.
Well, I love this method. Maybe you will too, maybe not. By the way, there really is no reason you couldn't try this with a battery powered drill and an extension. Give it a whirl! (Pun intended)
If I get around to it, I will show you my even lazier way of drilling for my stretchers. It doesn't require the use of an angle gage, which is a plus.