Random part of the day: Arch 1X12X3

An excellent piece. Very sturdy and good fun for shaping. Curious what the changes have been to warrant four different part numbers though.

@Miyakan:
Some of the arches have had the actual arch profile tweaked to better match other parts. The 1x6x1 arch, for instance, had its pant legs hiked up so the 1x4x2/3 double bow would fit neatly underneath. Another thing that has changed on some is the thickness at the peak of the arch, which caused a few problems as that change happened right as 79003 was designed with the previous arch being crucial to form round windows. At the same time, I think the internal bracing for that arch (1x6x2) was tweaked as well.

I can't say for certain what changed with this specific arch, as I don't have easy access to any of the ones I own.

An interesting thing about some large arches like this is that they are made of a different (stronger) variety of ABS.

@Brickbuilder0937:
Are you sure it’s ABS? I know there’s another material used for regular opaque parts, which I believe is currently used for cheese wedges (to keep them from splitting at the low end), but I was under the impression that it’s a completely different material.

I don't find this part very useful since my mocs aren't that big, but I can see the appeal if you are building larger structures and stuff.

Should be called the Fibonacci arch with those dimensions

@MeisterDad said:
"Good castles have arches."

Did you mean, 'good castles follow arches'? ;)

It's always so satisfying to join two partly separate structures by slapping one of these bad bois in-between them.

Always thought of these as the 6090 arches--my first two (black and grey) were with that set--and the only ones for quite a while. In more recent times, this makes me think of the tan one that comes with 4480. And having used it for a bridge, I always think of that too.

@PurpleDave said:
" @Miyakan:
Some of the arches have had the actual arch profile tweaked to better match other parts. The 1x6x1 arch, for instance, had its pant legs hiked up so the 1x4x2/3 double bow would fit neatly underneath. Another thing that has changed on some is the thickness at the peak of the arch, which caused a few problems as that change happened right as 79003 was designed with the previous arch being crucial to form round windows. At the same time, I think the internal bracing for that arch (1x6x2) was tweaked as well.

I can't say for certain what changed with this specific arch, as I don't have easy access to any of the ones I own."

From looking at the pictures, the first version had the curve going all the way to the bottom. The subsequent three versions from 2010 onwards have the slight vertical before the curve starts to allow plates and tiles to be up against the base. I'm guessing the other variations are more internal. There is a surprising amount of overlap in the production years of the later versions though.