Arbor travel

BillConnerFASTC

Well-Known Member
I didn't want to further the hijacking of Rick's Book thread but two posts:

Not to drag this too far off topic (just ordered my copy - can't wait to read it!), but how does the front-loading arbor hold "more weight in less space"? Is the arbor taller than a traditional arbor to allow for space to be left in between the shelves without reducing the total weight able to be held? Or is it the same height as a regular arbor, with the understanding that for the rare time when the arbor is fully loaded, the shelves will become mostly irrelevant? Are you basing the increased capacity on the inability to load bricks into the top several inches of a traditional arbor because of being unable to angle the brick in? And finally, how much lighter is each brick as a result of cutting a handle in it? I would think this would add up to a significant amount just on its own, but please feel free to correct me - that page on your website is the first and only information I've heard about this.
Michael

You have the answer; the elimination of the tipping height is were the gain is made. However, the shorter the arbor the greater the impact, the longer the arbor the less. But for a given payload the front loading arbor is 8 to 10 inches shorter, on average.
But the arbor itself is also heavier - 135 pounds vs 90 pounds. The shoes are heavier - 20 pounds vs 6 pounds. We need fewer bricks to hit pipe weight allowing for more bricks for live load.
The length savings are actually minimal - maybe 2% of travel - but with a move to 50 foot max on fly towers to comply with fire codes, 2% is significant.
But there are other benefits. The 10 inches reduction might be the difference between the loader having to crawl off the gallery and into the well, or being able to load safely from the gallery. And not having to crawl into the well might allow for a compliant safety rail on the arbor side of the loading gallery. The benefits of front loading kind of cascade a bit in quite significant ways.
But, of course, the geometry of each existing theatre is different. And how do we get the architect of the next theatre to get it right?
Rick

High trim and travel - maybe in the other order - are the two major design issues for planning counterweight stage rigging. But even with a 50' stage an arbor bit increases travel significantly, much more than arbor design, and the additional cost of another foot of depth in the arbor pit is almost always insignificant.

Now, you say we can't afford an arbor pit. From my view, a 50' stage and no pit is same function as a 45' stage and 5' pit and no way that a 5' arbor pit isn't a lot less expensive than 5' of stage height. A lot. at least a couple of linesets (my monetary measure of stage features - like a catwalk across stage or house costs less than two linesets; alloy trim chains isn't 1/4 of a line set; a loading bridge might be two linesets depending; changing two pairs of legs to full stage travelers roughly one lineset; and so on. Just a way to help measure worth and set priorities.)

And to the point, what size arbor and arbor spacing are we comparing? If sets are on 8" centers, what's the maximum weight of a Brick House full to an equal height of conventional arbor with 6" wide weights? What about with 7" wide weights? I'll assume cut steel in all cases because I also assume the if you use lead on a conventional, you can use lead in a Brick House.

Not trying to disparage some specific advantages to the Brick House design, just trying to keep marketing out of a proper analysis.

FWIW I tend to recommend 50' high stages and 8' full walking access rigging pits, and find it a great place to put motors for counterweight assist on electrics and shells. Keeps all the motor stuff organized and compact. Share a stair to orchestra pit so not much cost. Maybe a line set.
 
(my monetary measure of stage features - like a catwalk across stage or house costs less than two linesets; alloy trim chains isn't 1/4 of a line set; a loading bridge might be two linesets depending; changing two pairs of legs to full stage travelers roughly one lineset; and so on. Just a way to help measure worth and set priorities.)
I like the unit - something tangible that theater people can weigh - large enough that people don't glaze over due to big numbers, yet small enough that one or two might not be a big deal.
 
We are currently doing a re-design of our current rigging. One "goal" is to get rid of our lead weights.... so playing with arbor sizes has been a huge deal around this place. We already have short arbors (9'), oversized bricks (15 3/4") and also have double purchase to deal with.

Has anyone around here actually worked with the brick house arbor? It it actually easier to load? You would always have to tie back the purchase line. I would also be concerned about the brick below grabbing and being drug out by the brick you are pulling. Is this actually a factor? Steel against steel is not always a smooth action.
 
I'll assume cut steel in all cases because I also assume the if you use lead on a conventional, you can use lead in a Brick House.

One point that I meant to ask in the other thread but forgot - do we know if the Brickhouse arbor is designed to be compatible with traditional stage weights? Since the only photos on the website are 3D renderings, it's hard to tell for sure, but I can't quite tell if normal bricks would be compatible with the Brickhouse arbor, which might be a dealbreaker for me - not that their bricks aren't nice, but I'd hate to not be able to use any old/borrowed/rescued bricks if the need arose.
 
I don't know and maybe @RickBoychuk will reply but it would seem without the weight with hand hole, handling would be tougher. Also, unlike a conventional twin rod arbor, I would think widths varying could cause problems, with potential for off center weights.
 

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