As those who have dealt with it know, keeping all four sets of shelf pin holes at the same height as their counterparts is critical, and can be difficult, without a jig.
You can buy some nice jigs downtown. Alternatively, you can make your own using aluminum, acrylic, wood or even temper board or peg board.
The thickness of the jig will determine the results you get using self-centering bits. For example, a piece of 1/8” thick aluminum will allow the bit to go 1/8” deeper than a quarter inch one would, so this should be kept in mind for the end result.
When done, your guide may be permanent or disposable, depending on how you use the guide holes. For example, if your drill bit come in direct contact with the jig holes, and they do not have bushings, your jig will, essentially, be a disposable jig, because the holes quickly enlarge with use.
Another option and my choice is, use a self-centering bit. These are commonly used to drill holes for door hinge screws. When used for a pin hole jig, each jig pin hole is enlarged just enough to accept the self centering bit.
During actual use, and if necessary, the holes drilled with the self-centering bit can be chased with a larger bit, to bring them up to the size you need. This goes quickly and with minimal effort, since the self-centering bits have done all the real work.
The bits on self centering bits are not exposed, until they are centered in the hinge screw or another hole, and you push down. As such, they do not have any moving parts in contact with hardware. This makes them ideal for jig use, because they will not cause wear on the jig.
Too, these bits have a very limited depth of travel, so are well suited for these purposes. If you do have to deepen the holes made with the bit, you can use a stop guide. That may be an actual guide that stops the bit from going too deep, or it can be a piece of tape on the bit.
Inexpensive sets [of three] self-centering bits can be purchased at Harbor Freight. You can even shop around and find this kind of bit for the hole size you actually need.
[MAKING THE JIG]
For the actual jig, you can use anything you want. I prefer 1/4” thick acrylic, both because I had some laying around and because it makes it a bit easier to see what is going on. I cut mine about 1-1/2” wide and about 18” long.
Once I cut my strip to width, I marked each hole position (I chose 1” center to center). Then I drilled a pilot hole of about 1/8” inch. After that, I enlarged the holes to the size of the self centering bit. Because I used acrylic, I had to drill slow, to keep from fracturing the material.
[USING THE PIN GUIDE]
With the bit in hand, the jig is now ready to use. However, I wanted to be sure all holes would line up with other sets of holes, and that spacing would remain the same, if I had to make long runs.
To insure this, I grabbed a screw the same size as the holes I would be drilling. It would fit, sloppily, through the jig hole, but snugly into any hole I drilled. To get it to also fit the jig holes, I just wrapped some duct tape around it, until it fit well. When done, I had an indexing pin.
After positioning the jig and drilling my first hole, I inserted the “indexing pin,” which looks, suspiciously like a screw with duct tape on it pressed into that hole, to hold the guide in position, while drilled the remaining holes in that run.
Of course, I just repeated the process for each corner and, if needed, center back supports.
Once done drilling all the holes, I chased them with a bit the same size as the pins I would be using.
Because the self-centering bit drill fairly large holes, chasing the bits, to enlarge them, was simple. It required no real pressure, so there was little, if any danger of pushing through the cabinet side (generally, the bit pulls itself in and stops at the bottom).
The router type shelf pin hole jigs seem unsurpassed for quality of hole (splintering/chipping). This is due to the high speed [and using a sharp bit]. A dull bit can tear or chip a hole too.
If you don’t have a router, your router doesn’t plunge, you don’t have the right template guide, or have to add holes to an existing cabinet, the drill jig may be the best bet. Even then, an angle drill may be required for tight spaces.
The centering bit can be faster, but the little speed gain isn’t usually an issue, if the project will be used for decades. Worrying over a minute or two would seem penny wise and pound foolish.
If you go the drill route, remember, the bit in the self-centering bit sets can be replaced. You may be able to replace the stock bit with a brad point for clean cuts. However, you may need to shorten it so it cuts to the same depth as the original bit [and doesn’t blow out the other side of your cabinet].
Usually, using sharp metal bits at high speed will give pretty good results. As such, rather than using a cordless drill, like in the pictures, switching to a corded drill can give better results, since they usually run at higher speeds.
The higher speed of corded drills is the reason Kregg recommends using them, instead of cordless, for drilling pocket holes. You get cleaner cuts and the bits stay sharp longer. The same applies in other wood drilling operations.