Fine Points of Boring

Advice on matching the bore-hole dimensions of various boring machines to the requirements of metric-based frameless cabinetmaking systems. September 7, 2006

I recently purchased a used Blum Minipress with the seven spindle head attachment. I have 4 kitchen jobs in the pipe, so I want to set this machine up so anyone in the shop can make perfect gables. In the Blum 32 book, it says to drill 22 system holes in each side. It leaves me pondering how to produce the 22nd hole. It seems like I'd be better off drilling 2 system holes at a time! Does Blum expect you to drill 6 holes twice to get the 22 hole?

The drawer slides I use are the Blum 550 and the Accuride full extension ball bearing slides. If I used 21 holes, I'd be forced to make gables that are for L and R only. Because of the 550s, I need the bottom hole to be pretty low - 46.5mm off the bottom if memory serves correctly. Any illumination on this would be very much appreciated.

Forum Responses
(Cabinetmaking Forum)
From contributor A:
According to the Blum sys32 manual, your base gables should be 775 mm tall and if you bore the first hole at 46.5 mm, the gables will not be balanced anyway and you will need to make lefts and rights. Your doors will be balanced and you will have 10 mm reveal on top and 0 at the bottom.

With your setup and without a double line boring machine, you will need to flip the panels end to end to bore the back holes in either case, so if you make left and rights, the only time you will miss the 22nd hole is when you have a cabinet 775 mm tall, base or upper, without drawers, and you bore your door hinges at 62.5 mm, as recommended by Blum, you will need to bore one last hole to hand the hinge plate.

You will also need to be able to index the first hole and the subsequent 7 spaces accurately on both sides of your machine, so you can either build one or buy the Pearls Sticks, which work great. When we had the sticks, we bored for door hinges at 126.5 mm for a variety of reasons, to be able to place a rollout drawer in the system holes in base cabinets.

From contributor B:
Four kitchens in the pipeline and you're screwing around with seven holes at a time? Get a 2X25 line bore. Then, anyone can use it.

From contributor H:
4 kitchens are not enough to warrant an 11,000.00 plus time cost, which is what a double line bore costs. If there are many more kitchens in the near future and you can afford to take this kind of money without hurting, then do it.

From contributor R:
Where can you buy the Pearl Sticks? I have been looking for one and just can't find it.

From contributor M:
You can buy The Sticks through Louis & Company. They're called The Sticks by Metricks.

From contributor L:
You could probably get away with buying an inexpensive 13 head line borer. I bought a used Delta 13 head for $600, 5 years ago, to get me through a commercial job. I've been waiting for it to go, and when it does, I'll get at least a 23 head or get a double row 23 head. Look in the Machinery Exchange on WOODWEB.

From contributor P:
Do the small thirteen spindle drills work for boring system holes like Kiss or Pearls require? I have heard a lot of advice both ways and still haven't decided if I can get by with the thirteen spindle for awhile. We need it to be pretty accurate for slide installation.
Anyone used them for more than just shelf holes?

From contributor H:
The thirteen spindle machines are just as accurate as you. Just use the spring loaded metal dowel as a spacer. The problem is that you can't bore the back hole for the slides because there is not enough adjustment in the fence. That's why they are fine for shelf holes, which can be 37mm from front and back. You cannot bore 500mm from front for a tandem 21" slide. An economical and fast way of boring slide holes is a jig that Blum sells with 4 sliding tracks. I have used it and still do occasionally when my double line machine is busy. If you do a lot of repetitive sizes, you can get more than one set and dedicate to each slide configuration. We do mostly 3 drawer banks of 6/12/12, or 4 drawers 6/6/6/12, or 1 drawer 1 pull-out garbage 6/24. These are approximate without reveals for illustration purposes. One jig works for all of these. It's around 250.00. Takes less than a minute to accurately bore a side for 4 drawers. For several kitchens a week, a double line machine will pay for itself quickly, but is in the 10k range.