Who knows the answer

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benaround

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A co-worker asked me today what the mark on a measuring tape at every

19.25" is, It was the first time I ever knew it was there. Anyone know?
 
benaround said:
A co-worker asked me today what the mark on a measuring tape at every

19.25" is, It was the first time I ever knew it was there. Anyone know?
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It's used (or was) to space framing with 5 studs per 8' of wall.

It's not 19.25" it just a little under.

tapemeasure_stud_19pt2_OC.gif
 
8', or 96"/6 = 16" on centers.

8', or 96"/4 = 24" on centers.


Now, 8', or 96"/5 = 19-3/8" on centers.

It's a compromise when 16" OCs is over-built, but 24" OCs would not be strong enough. Still allows use of standard 8' building materials like drywall & paneling.
 
This mark, at the 19.2" point and thereafter, is known as the cubit. It is often also refered to as "the black diamond". As mentioned, it is a compromise between standard stud spacing of 16" and 24"
The history of the cubit goes way back to when God ordered Moses to build the Ark. My dictionary states that it is based on the length between the elbow and the wrist and varied between 17" and 21". When Horatio Stanley invented the tape measure in 1897, he decided to formalize the exact point as 19.2" as a convenience to carpenters since it is 8' evenly divided by 5.
If you doubt the veracity of this, then post or search the FineHomebuilding forum "Breaktime" at Taunton.com.
~Peter
 
I would have to say that I have learned something from a carpenter....Around here they sometimes use the 19 diamond spacing on there floor joist layout. And now we ALL know as much as, if not more than most carpenters.:D
 
peter said:
The history of the cubit goes way back to when God ordered Moses to build the Ark. My dictionary states that it is based on the length between the elbow and the wrist and varied between 17" and 21". [/COLOR].
~Peter
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A cubit is from the elbow to the end of the middle finger, as I have been taught. FWIW, mine is 19 3/4" and I think it's cool to find out that Stanley standardized it and put it on his new invention.
 
I was taught that this is the standard for military framing to save a stud every 8 ft. The measurement is marked by the black diamond. And that military built tract housing is framed on this dimension.
 
In my opinion the similarity between the black diamonds and 'cubits' is strictly a coincidence. I am fairly certain Noah was not using standard 8' building materials in his time. ;)

19.2" is simply 1/5 of 8'


From Stanely Tools
What is the diamond marking on tape rules?

Answer The black diamond marks every 19.2" on our tape rule blades are for spacing joists and studs. Several wood product manufacturers offer Engineered Lumber as a substitute for conventional lumber. Span tables for these lumber products provide ratings for spacing of 12in., 16in., 19-3/16in., and 24in. If you multiply these dimensions by 8, 6, 5 and 4, respectively, you'll notice that you come up with 96in., the length of the panels that will be used for sub-flooring or sheathing. Engineered Lumber is usually specified by the architects and engineers who draw the plans. They take advantage of its strength by using fewer joists or studs where codes allow.
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From Merriam-Webster Online Dictionary

cubit

Main Entry: cu?bit

Pronunciation: \ˈky?-bət\

Function: noun

Etymology: Middle English, from Latin cubitum elbow, cubit
Date: 14th century

: any of various ancient units of length based on the length of the forearm from the elbow to the tip of the middle finger and usually equal to about 18 inches (46 centimeters)
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"the similarity between the black diamonds and 'cubits' is strictly a coincidence"
And the similarity between 12 inches and the length of someone's foot is also strictly a coincidence. Yeah right!
~Peter
 
too many cubits

too many cubits

cubit (Arabic, new) = 0.480 m = 3/2 feet (Arabic)
cubit (Greek, Attic) = 0.617120 m = 2 pous [Greek foot]
cubit (Hachemic, Arabic) = 0.640 m
cubit (Hebrew) = 0.555 m
cubit (Hebrew, sacred system) = 0.640 m = 2 zereth [Hebrew foot]
cubit (Moroccan pre 1923) = 0.533750 m = 7 tonni = 7/8 pic
cubit (Persian, long) = 0.640 m = 2 zereth [Babalonian foot]
cubit (UK) = 0.4572 m = elbow to tip of middle finger = 3/2 foot = 9/2 hands = 6 palms = 18 inches = 216 lines
cubito (Somalian pre 1950) = 0.560 m = 1/7 top
cubitus (Roman cubit) = 0.4416 m = 3/2 pes = 1 palmipes + 2 palmus
 
too many cubits
Indeed that is the problem. In those days of yore, the cubit was based on the distance between the king's elbow and the base of one of his fingers. This of course varied all over the place, depending on who the ruler was and how old he was. Mr. Stanley did us all a favor and standardized it at 19.2". Or, as you prefer, .48768 meters.
So the next time some apprentice asks what are those black diamonds, you can truthfully tell them that they are the cubit marks and explain about joist spacing and all that.
Thank you for your research.
~Peter
 
God said to Noah "I want you to build me an ark (so many) cubits by (so many) cubits."

Noah said to God "What's a cubit"

Bill Cosby 196?
 
brian john said:
God said to Noah "I want you to build me an ark (so many) cubits by (so many) cubits."

Noah said to God "What's a cubit"

Bill Cosby 196?
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"Let's see, I used to know what a cubit is..."


1963
 
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