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Understanding Blum Soft Close Euro Hardware #2: Reveal and Relative Door Dimensioning

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Blog entry by DBrown52 posted 11-03-2015 03:52 PM 976 reads 0 times favorited 7 comments Add to Favorites Watch
« Part 1: Arm Crank and Plate Height Part 2 of Understanding Blum Soft Close Euro Hardware series no next part

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



7 comments so far

View Dutchy's profile

Dutchy

2012 posts in 1630 days


#1 posted 11-03-2015 04:15 PM

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.

-- My englisch is bad but how is your dutch?

View DBrown52's profile

DBrown52

65 posts in 1192 days


#2 posted 11-03-2015 04:26 PM

“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.

View Dutchy's profile

Dutchy

2012 posts in 1630 days


#3 posted 11-03-2015 06:51 PM

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.

-- My englisch is bad but how is your dutch?

View DBrown52's profile

DBrown52

65 posts in 1192 days


#4 posted 11-03-2015 07:15 PM

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.

View Texcaster's profile

Texcaster

1138 posts in 1135 days


#5 posted 11-03-2015 09:38 PM

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.

-- Mama calls me Texcaster but my real name is Mr. Earl.

View DBrown52's profile

DBrown52

65 posts in 1192 days


#6 posted 11-03-2015 10:01 PM

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.

View Dutchy's profile

Dutchy

2012 posts in 1630 days


#7 posted 11-04-2015 08:02 AM

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.

-- My englisch is bad but how is your dutch?

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