# Understanding Blum Soft Close Euro Hardware



## DBrown52 (Aug 30, 2013)

*Arm Crank and Plate Height*

A fantastic upgrade to kitchen cabinets is the newer soft close Euro hardware for doors and drawers. When I decided to build the kitchen for my new home (another story for another day), I knew I wanted this feature and went with the most popular brand: Blum.

So why the blog? I'm writing this because Blum hardware - like all cup hinge and undermount slide Euro hardware - is incredibly confusing. I'm an engineer who lives for reading diagrams and schematics and I still found the learning curve very steep. I spent days looking at Blum's documentation and prowling cabinetmaker forums trying to figure these things out. So I'm writing this blog to transfer some of my learnings to others and I'll start with the cup hinges. Rather than paint by numbers, I will try to explain the logic behind the system so you can make sense of the technical documentation. This entry will hit on the topics of "arm crank" and "plate height". "Reveal" and "bore distance" will be covered later.

This will be a long document so if you only read one thing, read this:

*If you are a traditional American weekend-warrior woodworker, Blum hardware was not designed for you. It was designed for a production level cabinet shop producing standardized frameless cabinets in Europe.
*

Of course, that doesn't mean you can't use them with great success, because you can. What it means is you need to take off your craftsman/artist hat for a minute and think like an engineer to understand the design of the product. To do so, take a look at this configuration straight from Blum's documentation. It represents frameless, full-overlay cabinetry that dominates Europe and is very popular in the US today.









I'd bet dollars to donuts this was the first configuration Blum's engineers dreamed up since it perfectly suits their target market. So why does this matter to you if (like me) you're building traditional face frame inset cabinets?

*Correct use of the Blum hinge is based on selecting the hinge configuration and/or adjusting your cabinet design so that it reverts back to functioning like a frameless cabinet. Understanding this is "thinking like an engineer".*

To get from the frameless, full-overlay style to a framed inset style, Blum engineers make two steps. First, a move of the door to a frameless, inset style.









Notice the shape of the hinge arm has changed. This is because the door now has to swing out and around the panel, rather than just pivot. This is referred to as the "crank" of the hinge. So we've gone from a "straight arm" hinge to "full crank" hinge. And there's a "half crank" that falls in between. This jargon is part of what makes the curve so steep.

Second, another step changes this frameless inset style into a framed inset style. The easiest way is to set our face frame on the carcass so that the panel is flush to the inside of the frame.









Congratulations, we now have an inset face frame style cabinet by adjusting our cabinet design to the hinge. But, we've lost some space inside the box. Doing this with a 1-1/2" face frame costs you 3/4" of space for every door assuming 3/4" thick panels. In most of my kitchen, I was ok with the loss, but I had a couple of smaller cabinets where I wanted to conserve as much space as possible. And maybe you are at the point where you can't redesign the cabinet, so we need another solution.

 
An alternative is to simply tuck a block-out board behind the face frame so the first three inches or so are flush like it was a panel.









I found this solution to be aesthetically unpleasing, so I moved on from altering the cabinet design to altering the hinge configuration.

Now is a good time to introduce another point of confusion. The hinge is not bought as a single component. The hinge "arm" and "plate" are separate components that click together. The arm/cup attach to the door, while the plate connects to the cabinet carcass. The figures above are of a "full crank arm" attached to a "0mm plate" (notice the H=0 in the diagrams). The plate comes in 3mm increments up to 9mm. Increasing the size of the plate in this picture effectively moves the hinge and door to the left. See where I'm going with this? Functionally, it is the same as introducing a blockout board. The "plate height" needs to be the same as the amount as the offset between the panel and the inside of the face frame.









As mentioned, the plates only go up to 9mm, so the face frame overhang can't exceed that unless we add a blockout board to augment. I found the combination of a 6mm plate and a 1/2" block to be the best option to use to get me out the needed 3/4" (there are 25.4mm in an inch). It looks better than a full blockout and functions just as well.
 
At this point, you may think I don't know what I'm talking about. If you've researched at all, you've undoubtedly seen this configuration from Rockler or Amazon or elsewhere.


















It utilizes a half crank arm and a special mounting plate that attaches to the face frame instead of the carcass and provides the remaining crank needed to swing out around the frame. You could attempt to use it, but I decided against it for two reasons. First, I read horror stories about mounting the plate to the face frame and I believe them with the angle of that screw. Second, I didn't like the idea of the torque from the opening and closing of the door being applied to the face frame instead of the much more rigid panel. These Euro hinges can be a little stiff, resulting in a great deal of torque about the pivot point on a wide door. I felt the risk of splitting the face frame was reasonably high with thousands of cycles found in a kitchen and I discovered instances of this happening to professionals.

At this point, I hope the concept of arm crank and plate height are clear enough that you can now understand the technical documentation on Blum's website. In the next blog entry, I'll attempt to explain the interplay between "boring distance", "reveal", and the sizing of your cabinet doors.

Thanks for reading
Dave


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## pintodeluxe (Sep 12, 2010)

DBrown52 said:


> *Arm Crank and Plate Height*
> 
> A fantastic upgrade to kitchen cabinets is the newer soft close Euro hardware for doors and drawers. When I decided to build the kitchen for my new home (another story for another day), I knew I wanted this feature and went with the most popular brand: Blum.
> 
> ...


You made your points very clearly. Well written and informative. I will be tuning in for chapter two.

I tend to use blocking for lower doors, and they seem fine in that application. For upper cabinets, I see your point that large blocking doesn't look the best. I tend to use Rockler self closing statutory bronze hinges for inset doors. They are full crank, H=0 by your definitions. They work well and I like them because they are black / oil rubbed bronze in appearance. The self closing feature is nice, but they are not soft closing, so they need a cork or rubber bumper. Install on the Rockler hinges is simple, but they do require blocking.

Thanks again.


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## Redoak49 (Dec 15, 2012)

DBrown52 said:


> *Arm Crank and Plate Height*
> 
> A fantastic upgrade to kitchen cabinets is the newer soft close Euro hardware for doors and drawers. When I decided to build the kitchen for my new home (another story for another day), I knew I wanted this feature and went with the most popular brand: Blum.
> 
> ...


I am an engineer and went thru the learning curve a year or so ago. I ended up making a number of trial doors and drawers to learn how to get it done.

There are three things to remember…..accuracy…..accuracy. .accuracy.

The holes and hinge cups have to be accurately done…..jigs to do this were a key to my success.


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## Dutchy (Jun 18, 2012)

DBrown52 said:


> *Arm Crank and Plate Height*
> 
> A fantastic upgrade to kitchen cabinets is the newer soft close Euro hardware for doors and drawers. When I decided to build the kitchen for my new home (another story for another day), I knew I wanted this feature and went with the most popular brand: Blum.
> 
> ...


Nice contribution. I'm looking forward to to see the next one.

*Redoak* The systeem of euro hinges (and other euro hardware) is developed to use in combination with a 32 mm (semi) automatic drillpress. Today the system is mostly used with CNC machine made cabinets. This euro system is also called system 32.
Some pictures of a 32 mm drill


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## Redoak49 (Dec 15, 2012)

DBrown52 said:


> *Arm Crank and Plate Height*
> 
> A fantastic upgrade to kitchen cabinets is the newer soft close Euro hardware for doors and drawers. When I decided to build the kitchen for my new home (another story for another day), I knew I wanted this feature and went with the most popular brand: Blum.
> 
> ...


Dutch….yes I know that. When I did the cabinets I built a jig to use a plunge router and was able to quickly and accurately place the holes. I did all of them for 12 upper and 12 lower cabinets in an afternoon. Production shops may use a CNC but many smaller shops still use jigs.


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## DBrown52 (Aug 30, 2013)

DBrown52 said:


> *Arm Crank and Plate Height*
> 
> A fantastic upgrade to kitchen cabinets is the newer soft close Euro hardware for doors and drawers. When I decided to build the kitchen for my new home (another story for another day), I knew I wanted this feature and went with the most popular brand: Blum.
> 
> ...


Thanks Willie. I like that Rockler hinge. I'll keep it in mind for future furniture projects. Oddly enough, it's described by Rockler as a frameless inset hinge. That's so confusing for an amateur like me.

Dutch and Redoak, accuracy and precision is definitely the name of the game here and the Blum design leads to some tough dimensions to repeatedly nail, justifying those $10K+ CNC machines production shops use. It's even worse for us poor Americans who want to work in inches, not mm. Once I started to understand the design of the hinge, I was able to make it work with my skills and tools. But that learning curve was definitely steep.


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## DBrown52 (Aug 30, 2013)

*Reveal and Relative Door Dimensioning*

In the last entry, I explained that in an inset face frame application, you can utilize the appropriate arm crank, plate height, and blockout boards to make the Blum hinge operate like it's in frameless cabinetry - its optimal configuration.

Of course, the appearance needs to be as good as the operation. In traditional face frame inset cabinetry, this means a uniform gap around the sides of the doors, known as the "reveal". Industry standards seem to dictate a reveal of 3/32" all around in kitchen cabinetry. This about as tight as you can get without running the risk of stuck doors in the summer.










This reveal means you have to dimension your doors relative to the face frame openings. If you use integers for your face frames like me, you get some nasty final door dimensions, especially for cases where there are two doors in one opening. Take the above case of a 24" wide opening for two doors. How wide is each door? There are three gaps, so the dimension is 24" minus 3/32" times 3 gaps divided by two doors. That is a door width of 11-55/64". Yuck.










Dealing in 64ths of an inch is for production shops with high precision equipment, not woodworkers with pencils and old contractor saws. To handle this, I steal a 1/32" back by setting the middle reveal to 1/16". In our 24" opening, this gives a final door dimension a more manageable 11-7/8".










A very light pass on the jointer on one side of each door brings the gap back close to 3/32". Yes, that means one stile is 1/64" wider than the other. No, you can't tell and the inexact size of the middle reveal has no bearing on the operation of the hinge.










So that covers relative door dimensioning and the relationship to reveals. I haven't even mentioned the Blum hinges. Disappointing, I know. So why am I fussing so much about door dimensions and reveal? Isn't it mostly aesthetic? Actually no, it's very important functionally because the reveal used dictates not only the door dimensions, but also where the hole gets bored for the hinge cup. If those three aren't in harmony, the door won't look good or function well. I was originally going to cover the concept of "boring distance" here, but I think we'll push it to the next entry in this series.
Thanks for reading
Dave


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## Dutchy (Jun 18, 2012)

DBrown52 said:


> *Reveal and Relative Door Dimensioning*
> 
> In the last entry, I explained that in an inset face frame application, you can utilize the appropriate arm crank, plate height, and blockout boards to make the Blum hinge operate like it's in frameless cabinetry - its optimal configuration.
> 
> ...


Isn,t it time to change to a metric system?

But also where the hole gets bored for the hinge cup. I don't understand what you exactly mean but maybe in the next contribution iit becomes clear.


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## DBrown52 (Aug 30, 2013)

DBrown52 said:


> *Reveal and Relative Door Dimensioning*
> 
> In the last entry, I explained that in an inset face frame application, you can utilize the appropriate arm crank, plate height, and blockout boards to make the Blum hinge operate like it's in frameless cabinetry - its optimal configuration.
> 
> ...


"Isn,t it time to change to a metric system?" - From your mouth to God's ear, my friend.

I'll try to explain the boring distance better next, but here is a picture from the Blum documentation that might help.









You bore a hole in the door stile for the hinge cup to slide into. The distance from the edge of the stile to the edge of this hole is the "boring distance" (dimension B in the image). The chart shows there is a direct relationship between reveal and boring distance. For a 0mm plate, the boring distance and reveal sum to 7mm.


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## Dutchy (Jun 18, 2012)

DBrown52 said:


> *Reveal and Relative Door Dimensioning*
> 
> In the last entry, I explained that in an inset face frame application, you can utilize the appropriate arm crank, plate height, and blockout boards to make the Blum hinge operate like it's in frameless cabinetry - its optimal configuration.
> 
> ...


Now I understand what you are meaning. Please try to understand that my english isn.t that good.

in practice use you have to make a choice to make always the same reveal. Mostly this is 3 mm. with means that your boring distance always is four. After you mounted the doors you can now change the reveal between 1 and 5 mm. When you have a boring distance of 6 you are still able to make a reveal of 3 mm. It is important that this boring distance in all your cabin doors is the same.
When you also make cabinets with overlay doors you can still use the same 4 mm distance. The overlay than will be, dependent of what underlay (3+,6 +or 9+) you use 6, 9, 12 or 15 mm. This means in practice that the overlay is adjustable between 4 en 17 mm.

I always use the same 4 mm boring distance.


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## DBrown52 (Aug 30, 2013)

DBrown52 said:


> *Reveal and Relative Door Dimensioning*
> 
> In the last entry, I explained that in an inset face frame application, you can utilize the appropriate arm crank, plate height, and blockout boards to make the Blum hinge operate like it's in frameless cabinetry - its optimal configuration.
> 
> ...


Good points Dutchy. The hinges do have that reveal adjustment, but I pretend they don't in case I mess up the execution. And I haven't really looked into overlay doors that much.

In the next entry, I'll show how you can calculate the placement of the center of the cup hole based on the reveal. Fortunately, it works out that a center 7/8" from the edge gives almost exactly a 3/32" reveal. With the 35mm cup, it is the equivalent of a 4.6mm bore distance. So we're landing in pretty much the same place. Your tools and tape measures probably have mm graduations on them, which suits the Blum system. Over here, we're working in 1/32" graduations so it takes some thinking and unit conversion to use the Blum literature.


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## Texcaster (Oct 26, 2013)

DBrown52 said:


> *Reveal and Relative Door Dimensioning*
> 
> In the last entry, I explained that in an inset face frame application, you can utilize the appropriate arm crank, plate height, and blockout boards to make the Blum hinge operate like it's in frameless cabinetry - its optimal configuration.
> 
> ...


Dave, I can understand your confusion with system 32 if you are new to it. Just remember, the system is so efficient it has deskilled an industry. Now is all about the doors and bench tops one makes.


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## DBrown52 (Aug 30, 2013)

DBrown52 said:


> *Reveal and Relative Door Dimensioning*
> 
> In the last entry, I explained that in an inset face frame application, you can utilize the appropriate arm crank, plate height, and blockout boards to make the Blum hinge operate like it's in frameless cabinetry - its optimal configuration.
> 
> ...


Bill, that's undoubtedly true. But this site is mostly hobbyists like me who probably have no interest in a production scheme like system 32. So I'm just sharing my process on how I understood the hardware requirements and worked them into my existing skill set so I too could use this awesome line of products. Thanks for reading and taking the time to comment.


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## Dutchy (Jun 18, 2012)

DBrown52 said:


> *Reveal and Relative Door Dimensioning*
> 
> In the last entry, I explained that in an inset face frame application, you can utilize the appropriate arm crank, plate height, and blockout boards to make the Blum hinge operate like it's in frameless cabinetry - its optimal configuration.
> 
> ...


Thanks so far.
I,m looking forward to see the next contribution.

From your mouth to God's ear. I don,t know this saying. Does it means that you like it what i have written or that it is something unmentionable.


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