|Forum topic by Kelly||posted 02-18-2015 06:16 PM||2299 views||0 times favorited||4 replies|
02-18-2015 06:16 PM
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. You can also use temper board for what, essentially, is a disposable jig, because the holes quickly enlarge with use.
Some of the commercial jigs use sleeves to avoid enlargement of the holes. Another option is, use a self centering bit, which is used to drill holes for door hinge screws and such on a jig with pin holes enlarged to accept the self centering bit.
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.
Inexpensive sets [of three] of these bits can be purchased at Harbor Freight.
For the actual jig, you can use anything you want. I prefer 1/4” acrylic, both because I had some laying around and because it makes it a bit easier to see what is going on.
Once I cut my strip to width (I chose 1-1/2”), I marked each hole position (I chose 1” center to center). Next, I drilled a pilot hole of about 1/8” inch. After that, I enlarged the holes to the size of the self centering bit.
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 that screw with duct tape on it) into that hole, then 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).