Methods of 32 mm system layout

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Different interpretations on the 32mm system. (Cabinetmaking Forum) March 23, 2003

Is anyone interested in discussing how they lay out 32mm casework?

The Blum Pearls booklet outlines a method for laying out 32mm system hole locations. It starts the first hole at 44.5 mm, splits door and drawer face reveals on hole centers. It recommends using balanced panels, which gives a top reveal of 14 mm in the Pearls system.

I basically made up my own system years ago. I have been starting my first hole at 38mm, mainly because a Blum 230 slide sits neatly on a 3/4" bottom panel with 1/4" clear below the drawer box. I have been splitting my reveals at 22 mm below the hole, because with a Blum slide that puts the drawer face 1/8" below the bottom of the drawer box. I line bore with a machine that drills 2 rows of 32 holes at a time. I use "The Stick" on a Blum Minipress to locate my hinges, so drilling hinges the same distance from the top and bottom of the door is not necessary.

A 14mm (9/16") top reveal seems a bit large to me. Balanced end panels sound like a good idea, but unless *all* your boxes have balance ends, you would be asking for trouble in my shop...

I did notice an Accuride slide can be mounted in the first hole with the "Pearls" layout. Are there any other good reasons for using 44.5 mm as a starting hole location? What are you doing?

Forum Responses
(From WOODWEB's Cabinetmaking Forum)
From contributor K:
My starting hole is 37mm from the panel bottom edge for the same reason you cite - Blum 230 works with 5/8" or 3/4" thick bottom. Use the next hole up to install Blum 430 full-extension slides with no thinking required. I put the split line halfway between the holes - 16mm - to get maximum headroom in the drawers and also to keep from confusing myself any more than usual.

Kitchen base panels are 769 mm high. Vanity and desk drawer pedestals are 609mm. Drawer/door top-reveal varies with countertop edge treatment but 3mm gap over door/drawer top is maintained.

44.5mm as a starting hole was probably selected because it made perfect sense to someone for reasons only known to them. Where to start would depend upon what drawer slides the system is designed to accommodate, I would think.

My first hole used to be 49.5 from the top or bottom as it was centered, but I have no idea who decided that. We have since thrown that method out the door and now only drill holes where they are needed. Much easier training a new person when they only have one hole to choose from for drawer slide placement, etc.

From contributor S:
Iíve just finished setting up my hole patterns. As with Blum I'm setting the first hole at 46.5mm. This allows me to use their spacer blocks for pullouts. I think I need to reduce panel height to get a proper top reveal. Do any of you have advice on purchasing a DBL row line-boring machine?

You are all on to something that you've each arrived at personally. The hardware and drawer systems are the primary component of choice. If you used Metabox or Zargen drawers the first hole would be different. For uppers the first hole is even more discretionary since drawers are not the usual consideration. When we used to have schools on 32 in the 80's we always explained that primarily the first hole is a choice based on hardware used. It seems that this conclusion is still the one being reached.

Jon Elvrum, forum technical advisor

From contributor J:
A few years back Mark Poole gave the most logical explanation of where the first hole should start and why. There are only 4 possible starting points (outside of the fact these can be increased or decreased incrementally.) The gist I remember is that (as a starting point, anyway) panels and fronts should all be in increments of 32mm steps since the holes are. You can either start a half step up or full step up so to split fronts on or between holes. Reveal between fronts must be taken into account along with whether fronts are centered top to bottom or shifted down.

Jon, I'm surprised to hear you suggest changing a first hole based on brand name as much as I am surprised to hear you suggest a different starting hole for different type boxes.

To choose a starting point for unknown reasons is just as ludicrous as basing the first hole position purely on brand name. The brand can influence the choice of one of those four starting points, but that should be it.

Good grief! If you use Blum's system you're locked into Blum. If you use Grass's system you're locked into Grass. Use the 32mm system and force suppliers to follow suit. At least some have started putting holes on 32mm centers. Now they need to remember *increments* of 32 above and below.

Oh, the four starting point options. 16mm, 32mm and (for my 4mm reveals and a shift down) 14mm and 30mm. This doesn't necessarily mean a hole at 16mm and so on but rather holes indexed from 16mm. That first hole could be at 16mm or 48mm or 80mm, etc.

I use 46.5 also as this is the layout for true32 - I'm not smart enough to remember why exactly that was chosen!

I would prefer having 14mm reveal on top but live with 3mm in order to have balanced panels and stay within my system. My doors are balanced but I don't drill from both top and bottom but use the Grass extension guides on drill to drill all holes from bottom reference.

I bought a Marcon double-line drill used for $4000 - it's a good machine and has never given me any problems for over 2 years. I've seen the Ritter used for more in the $5000 up range - it seems to be a good machine from what I have read and heard.

From contributor J:
Your panels aren't balanced or you'd start at 48mm. Why don't you add 11mm to jams underneath counters, which is almost all base cabs? 38mm tops foul up incremental jams above them anyway.

From contributor T:
I know very little about the way the 32mm system is supposed to work. But apparently there are a few different ways to use it.

I have been centering my holes in the panel - this may be the balanced panel mentioned above. I do it this way so there are not right and left sides when assembling the cases. It works for that, but I have recently decided on drawer cases to not line bore those sides, but only drill for the drawer runners. Using the line bore holes seemed to make fitting the drawers too time consuming.

I realize that my method is not the way to fully utilize the 32mm system, but it does work with American sizes.

What is a jam? Is my idea of a balanced panel correct? Do you need to use certain height drawers to make use of the line bore holes?

35mm to center of first hole off bottom or top edge works for 5/8" or 3/4" material and use a balanced panel/split reveals on holes. Grass has pretty good layout sheets and diagrams - gives panel heights, door and drawer heights. I do have to move up one hole for Accuride full extensions, though.

Always happy to surprise people. The truth remains that there are a lot of possible options. Over the years first hole from edge has been 32 (Grass before 1988) 35 Mepla for a long time and 37 which was 35 +/- a "fudge factor" controllable by the inherent adjustment in plates and/or hinges. It's easy to look backward and see the changes that have led to the homogenous 37mm but first holes do vary precisely because of the actual drawer guide used and the thickness of the material you employ. If that's a surprise, so be it. I wasn't "advocating" but "reporting" a reality that exists.

Jon Elvrum, forum technical advisor

I use the Blum Pearls, but my first hole is not at 46.5. It's at 12.5 + 32 which is 44.5. I have 44.5 before the first hole and 44.5 (or 12.5) after the last hole. So all of the panels are an increment of 25 + a row of 32's. Bases are 793---30" uppers are 761 (25 + (23*32)). I can use bottom mount drawer slides or metabox. I split on a hole.

From contributor S:
Okay, there may be a little truth in what Jon is saying. I have been using tandem slides and the only way I could figure to mount the bottom pullout was to use their plastic space blocks turned on the side. If I'm missing something, someone please speak up.

From contributor J:
That's what I do and you're not missing something, Blum is. Their slide is the best of that type but their hole patterns were engineered by someone who has no clue what increments of 32 relates to, or for that matter what round numbers are in metric or Imperial. I mean, look at all the holes on that thing and read the dimensioning sheet. Good grief. One hole for up top, another hole for down below, another for Monday and another for tomorrow, which never comes.

Jon, no offense was intended, but I was just surprised at your stance. As you mentioned, the "reality" of poorly designed hardware, even by the biggies like Grass and Blum, forces work-arounds as one works up and down the ladder of holes in a jamb, changes heights of fronts, or changes hardware. ("Jam" is a word we use out here in the sticks for bulkhead or end.)

Outside of P2P arguments, if one sets up a system using conventional hardware and more recent system hole borers it must/should be based on something in increments of 32mm, otherwise there's no system. To each his own on that. Why then are there all these claims of "systems" that have so much in conflict with that magic number of 32?

From contributor K:
Any slide which is bottom mounted and used often enough is the one that probably should dictate where a starting hole is placed. This is important if you're trying to utilize as much of the vertical dimension as possible - gaining maximum headroom per drawer and eliminating useless drawer-front hangdown or "clearance". My notion was since I like the bottom-mounted Blum 230 and 430 slides, they would dictate the starting hole. It is positioned as low as possible to keep the bottom drawer box or roll-out shelf from having excess space under it. Some of the drawer stack arrangements I have seen are wasting an entire drawer or additional headroom because of offsets and clearances worked in for no useful purpose. When a side-mounted drawer is used (such as most Accuride, Grant, KV, etc.) the hole location doesn't matter since the drawer member is placed to position the drawer "in system" so to speak. I suppose in the great Cosmic Scheme it doesn't matter much but I use the "less wasted space" deal for part of my talk with customers. (Everyone seems to get all giggly about "maximizing storage space.") An extreme example would be a stack of 7 drawers in a 769mm base for a dental office with five of them having about 3 1/4" of headroom and two having about 4 1/2" headroom.

"Jam" is what I spread on toast. A "jamb" is what I use for right and left sides of a cabinet box. I think they're called "gables" in some neighborhoods.

The True32 system of Bob Buckley and Mark Poole has several pluses.

All hole indexing is from the bottom and front edge of *every* end panel (or gable or jamb).
All hole indexing is at the same offset from the bottom of *every* panel.
All panels are in 32 mm increments.
All doors and drawer fronts are in 32 mm increments less the reveal chosen by you, most True 32 folks are using 3-4 mm.
All doors are thus drilled for hinges equidistant from both ends and are thus balanced. Balanced doors are reversible doors (pairs can be flipped for grain and color match).
All cabinets can be stacked without a double reveal being the result (makes tall cabinets easy to install as stack of 2 or 3 short boxes).

The TRUE32 system is a *system*. There are no exceptions or deviations for special situations because it is well engineered. Order the book - it is well worth the price.

Just so I stay on topic, I start at 78.5, which is 46.5+32. I donít line bore, I just bore the holes I need, but they are all ďin systemĒ starting at 46.5 at the bottom and ending at 49.5 from the top. To add to contributor J's position, I use the half hole approach, 16+32-1.5 (half of 3mm reveal)=46.5.

Contributor T, to address a couple things you asked: jamb, gable, side, end, whatever you want to call it - itís the side of a cabinet. I like to employ the KISS method, so I call it a side.

This all ties together with the idea of balanced panels. I understand full well why people use balance panels, and if it works for you, by all means use it. I donít use balance panels for several reasons. First and foremost is I like for there to be only one way for a cabinet to go together. When the guy is putting it together, thereís only one way to do it, which eliminates any room for error. Another way to look at it is when you look at a cabinet, say itís a wall cabinet, thereís a left side, a right side, a top, a bottom, a back, and maybe a door or two. It doesnít have two sides and two bottoms/tops. Does that make sense?

I also developed my own naming convention so I can easily identify each piece. Take the left side, itís a WSL= Wall Side Left, or the bottom is a WBT= Wall BoTtom. With these simple three letter codes each part is easily identified, thus leaving no room for mistakes (hopefully). Take it a step further - to uniquely identify each part in a job, I add the job name and cabinet number to each part so I can easily keep track of parts. I do for the most part all commercial cabinets, and use the room number for a job name, so say Iím working in room 137 and Iím looking for the left side of cabinet number 27, thatís 137BSL27.

Hopefully that gives you some insight into why I choose not to use balance panels. There are also hardware considerations as well as reveal considerations.

As for certain height drawers, I typically use a Grass 6136 for the top drawer. I donít consider opening sizes - I look at the overall height of the cabinet in 32mm units. My typical base cabinet is 768 high, less toe. 768/32 is 24, so Iíve got 24 units to work with. It takes 5 units to fit a 7136 in, so I know the top drawer front will be 5 units, and that leaves me with 19 units to use for the rest of it. If this were a drawer over a door, my door would be 19 units or 19*32=608-reveal of 3 or 605. Top drawer would be 5*32=160-reveal of 3 or 157. Say itís a drawer stack, I like to go from smallest to biggest as I go down, 19/3=6.333333, not good, so how about 6/6/7, yeah. So the next drawer going down would be 6*32=192-reveal of 3 or 189, then another 189, then the bottom would be 7*32=224 less reveal of 3 or 221.

As long as I keep my drawer fronts or doors on multiples of 32 less the reveal, any combination will fit in a system hole. Itís foolproof. If you so desire, you can come up with the same type of deal utilizing balanced panels. I believe itís laid out in Blumís Pearls. Grass also has a similar layout. This particular system works for me. Whatever you do, it behooves you to come up with a system and stick with it.

From contributor D:
Contributor R, I caught your post in a thread below, where you stated:

..."I've taken interest in the discussions going on about how people lay out their 32mm panels. I find it interesting that people go through all the time and trouble to make "balanced" panels and such. Even if they bought a cheap PTP, all they would have to do is tell the machine what holes you want where, and press the START button. Few minutes later... DONE. Next part please."

I hope you don't mind that I brought it up to this thread for a response and to hopefully keep this (most interesting) dialog going.

First, I begin by stating that I donít own either a P2P (CNC router) or a line boring machine at present. I am, however, actively searching for a decent, used boring machine. I have visited shops that use both types of machines and have attended the regional hardware and machinery trade shows for the past several years, learning what I am able to about such machinery.

It's true that a P2P gives the capability to direct system holes just where you want them, yet it seems to me that there are some advantages to producing system holes with a double row line boring machine. If I did have a CNC router, I donít think I would want to drill holes that werenít absolutely necessary, which would slow production and increase wear and tear on the router drills, guide rails, and electronics. I could also take a certain amount of pride and pleasure in my shopís ability to produce cabinet parts with ďjustĒ those holes necessary to accomplish the mission of each custom cabinet. Then there is the matter of me being able to justify the machinery purchase, which may be no small matter indeed. Then there is the competition factor. We are all in a never-ending battle to gain ground on our competition. So why would I want to produce all those holes, which the fellow down the street has to do, with his low tech line boring machine?

A line boring machine, drilling 46 (2x23) holes a one time, is able to produce those holes at a faster pace and can be as accurate as even the most expensive CNC routers. The banding goes on before the holes go in, which eliminates the possibility of banding the wrong edge, sets up the part orientation and the holes are drilled exactly 37mm back from the front edge, without thinking, every time. With system holes the full length of the end panels, the finished cabinet can be configured any way you or your customer wants, now or any time during the life of the cabinet. Roll-outs can be added to base cabinets at any time, a pair of doors can be exchanged for a drawer bank at any time; no fuss, no muss, with ease and with full customer satisfaction. Once the cabinet parts are discriminately drilled, that cabinet is destined to be only what it was designed and bored to be.

True again, that an assembler can't put hardware into holes that aren't there. With all end panels fully drilled, labeled, and with the use of a few templates as guides, it's really not difficult for even a simple-minded worker (like me) to determine which holes to place the appropriate hardware. Certainly there are many views on ďwhereĒ to start the system hole, but once that decision is made, the remainder of the holes are 32mm apart and run the full distance up (or down) the panel, each and every time, for every end panel produced. If the question was asked (of face frame cabinetmakers) how wide do you make all your frame parts, Iíd bet most are producing frame stock of different dimensions for their own (valid) reasons. As a face frame guy for several years, I can say that I changed frame widths very often, sometimes from job to job, and for many different reasons. Like many others, my starting hole begins at 78.5 and thatís a done deal. I may change it in the future, for good and sufficient reasons, but then I will carry on with that single decision having been made, the rest falling neatly into place.

The cost of machinery is obviously a factor in deciding which way to go. Cost is also relative, as the larger shops are trying to decide which CNC to purchase, to replace the last two or three P2Pís they have had or currently own. For the small shop, or the start up shop, a CNC machine of high quality and capabilities might be a future consideration, but the line boring machine may well be the machine to put them in that most desirable future position.

From contributor R:
There is no doubt about it that a double row line drill can out-produce probably even the fastest PTPs on the market today. But I think that would only be true if you were running large quantities of parts.

In my other post, the main point I was trying to make is that I think people should try to overcome the sticker shock at the price of machinery, and look at its purchase from a business perspective also. I own a small PTP (HolzHer 207). Was it a good business decision? No. My machine sits idle collecting dust for all but 2 or 3 days a month. But the bottom line is that I could not efficiently do the same work my machine does when it is running. My $700 month payment hurts some months. But out of all the bills I pay, the machinery leases are probably the ones I complain about the least. I think about all the bad employees I've wasted money on in the past... and I'm still happy to own machinery (well, after 45 more payments!).

When I consider a new piece of equipment, I don't think of it as giving me a competitive advantage. The truth is there is always going to be someone out there with a bigger, better machine, etc. You would bankrupt yourself trying to outdo the next guy.

I think people should buy machines that solve their individual problems in their shops. We all have problems, but the solution to yours might not be the solution to mine.

From contributor L:
Contributor D, you offer several very eloquent suggestions with no actual experience utilizing either piece of equipment to support your assumptions. You've overlooked several capabilities of a modern machining center (which is different from a CNC Router).

Construction boring, grooving and routing are totally separate operations from a double line drill.

Any comparison based on speed should include aggregate rather than isolated run-times, don't you think? If speed is to be the criteria, where does a feed-through drill enter the decision process?

Taller panels requiring multiple movements, as well as short panels that may require bit removal, must be factored in for a fair comparison. These additional steps would not be required of a modern machining center of adequate y-axis length.

It is somewhat misleading to suggest "top-to-bottom" drilling is required in order to add or interchange components at some nebulous distant date. It is entirely possible to drill base panels to accommodate the same configurations without "top-to-bottom" drilling. This is especially important for shops that want a common base side panel. It is also quite possible to do this with a basic double line drill.

In the end, both types of machines can produce excellent parts. The most important thing is to purchase the type of machine that suits the talent level of the business. It is far more important to produce profitable jobs on either type of machine than to be overwhelmed by either the technology or the justification process.

From contributor D:
Contributor R, your remarks got me thinking about CNC vs less automated equipment. I am in agreement with everything you had to say, just coming at it from a different point of view.

Contributor L, clearly speed of production is an aggregate of all processes required to get from raw panels to finished, ready to ship products.

My current (primary) panel processing goes like this:
Saw panels from cutlist to parts dimensions.
Band panels.
Groove panels.
Line drill.

Those are my basic panel processing procedures. There are obviously other tasks that need tending to, such as toe notching, skid plate boring and a few others, before the panels are ready for assembly. Most moldings and profiled (routed solid wood) are purchased or made using a shaper or electric router.

The operations I'm looking at that the P2P would handle (for me) would be parts dimensioning and line boring, and maybe toe notching. If I did have a machining center, Iím sure that I would come up with many other uses for the machine and hopefully be able to keep it employed a little more regularly than contributor R. Where are you at, contributor R? Maybe someone (close to you) is lurking about here and could outsource some work to youÖ

Contributor L, you do make some very valid points and offer sound considerations and I don't mean to say that I have it all figured out. I am satisfied I have a plan to get me where I want to go, with the resources I have now or soon will have available. Your last paragraph sums it up very well.

Keep it simple. Think mm and not inches. Start your first hole at 32mm, all your vertical measurements are in 32mm increments, and thus all panels are balanced.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor A:
Line boring: 37mm set back, down 49.5 from the top if no crown molding is going to be used. If a crown is used, move to 56.5 for your first hole, thus leaving a 10mm (3/8) reveal at the top. Base cabinet dimension should be 775mm (30 1/2"). If you are constructing commercial cabinetry only, base cabinet dimension should be 768mm. 24 exact increments of 32mm.

We teach to start at the top left corner and always index base and upper cabinets from that point. This accomplishes two things: 1. errors are thrown to the bottom back and 2. reversible doors. Some will argue this and instruct to start at the bottom, throwing errors to the top. Either way, the math is as long as you index from the same point. The other issue then arises concerning upper cabinet height. We suggest making them the same height and standardizing your manufacturing. The standard upper is 30 1/4", why not make them both the same size? The owner will never notice the difference and manufacturing the parts becomes much easier.