Boring Clean Shelf Holes
Here's a nice selection of practical advice for getting sharp-edged shelf holes bored in questionable panel material. April 9, 2008
Question
I am having a problem with tear out when I drill the holes for the adjustable shelves on my cabinet sides. I have a brad-point drill bit, and I have tried placing tape between the drill jig and plywood surface. However, it is unpredictable. The main problem is on the Chinese birch. Hardwood plywoods turn out pretty good. I have looked at other cabinet makers products, and see tear out from time to time. I have a high-end shelf-pin jig. Does anyone have a proven method? It is not a really critical situation, but I am sure you know the pain we cabinet makers go through when things are just 1/16" off.
Forum Responses
(Cabinetmaking Forum)
From contributor A:
Have you tried a brad point bit from Lee Valley? They bore the cleanest hole I have seen. China birch is very brittle and prone to tear out anyway which is a good reason to avoid it.
From contributor B:
Try increasing the rpms of the drill bit and entering the wood slower.
From contributor C:
The following has helped us, but it is slow! Let the bit stop spinning before you remove it from the hole.
From contributor D:
I use a plunge router and a spiral upcut bit instead of a drill. Works like a charm.
From contributor E:
Try a self-centering bit. I started using a self-centering bit and it cut way down on the tear out. I don't have a fancy jig, just pegboard, so I didn't mind drilling the holes out.
From contributor F:
Contributor D’s method is what I do (while lusting in my heart for a line boring machine). I build plywood jigs with 5/8" holes and use a 5/8" OD collar on the router. It works great. Peg board comes in handy for laying out the holes on the jigs. Tap on a 1/4" brad point bit in the desired holes and drill with a 5/8" Forstner bit.
From contributor G:
Not to be critical but unless this is the last job you plan on doing, I'd suggest spending the money and time you're wasting on hand drills, routers, tape and pegboard and purchasing a line boring machine. You're already paying for one - you just don't have it. It is entirely possible to be too thrifty.
From contributor F:
I completely agree. In my case there are tools that take priority over line boring machines while this business is growing. We're picking them off one at the time with the goal of staying out of debt.
From contributor H:
You don't know it, but a line boring machine is one of the most top priority tools if you're going to make cabinets with adjustable shelves. After you get one you'll realize it, especially when you drill your first 10,000 holes in an hour or two. How long would it take to drill 10,000 holes with a router, drills, bits and drill bits, and some crappy pegboard contraption? The thing will pay for itself before the check clears.
From contributor I:
I have the above mentioned drill and jig. The 5mm works great; the 1/4 inch tears out for me.
From contributor J:
I have to agree with contributor H - time is money, and how much is it costing you not to have one?
From contributor K:
I'll pile on too. I'm a one man shop. I bought a Delta line borer about a year ago after waiting too long. It seemed hard to justify the cost at first, but it saves so much time and makes such clean holes that I don't know how I managed without it. As contributor H said, if you're making cabs with adjustable shelves, you need to make it a high priority.
From contributor L:
I first bought a Ritter 13 spindle machine for about 2 grand, and it worked great. I now have a Laguna 23 spindle. Both are not just for shelf holes. I build frameless cabinets and a line boring machine is central to the whole process.
From contributor M:
Festool LR32 guide rail + router base + spiral bit (whatever size you want). It only works with Festool routers. It is much faster than a drill, but nowhere near as fast as a line borer. Holes are super clean. Spacing is 32mm, and can be used for system holes, too. You can buy long guide rails, or link smaller ones together if you need a long series of holes. It's very hard to maintain accuracy across 4 sets of holes when trying to use a drill template for runs longer than the template.
From contributor N:
I love my new Conquest Mini 13 (the American version of the Delta). I wish I had the $1500 5 years ago. I had miles of bookcases to build and my elbow started hurting while I was looking at the prints. I made the call, coughed up the dough and smile everytime I have to bore holes. Best $1500 I spent last year.
From contributor F:
To contributor N: Does the Conquest have metal gears? I'm inclining toward the Ritter entry level machine but have thought about checking into the Conquest.
From contributor O:
Yes, Conquest has steel gears in all their machines. One thing I found on the entry level machines is some run at slower at a slower rpm than others. This can be a factor so check it out.
