Related to MAKE 03, MakeShift
MakeShift 03: Vinnie Forgione's "Chikofsky & Cross" Honorable Mention
by William Lidwell
November 01, 2005
Vinnie's design makes fine use of common construction site materials to create a sturdy structure with plenty of strength and redundancy. My main quibble is that his design draws heavily on resources from the work site—I am not sure the site foreman would go for it. That aside, it is a pretty result. Love the images. Nice job, Vinnie!
What I like about this project is that it takes place at a construction site. I have to assume that all materials required for the mounting of "Super Cow" are readily available on site – along with skilled labor to boot!
For this project, I would build a mounting frame for the cow, attach the mounting frame to the jib of the horizontal tower crane, and then attach the cow to the mounting frame:
1. First, talk to the crane operator, the site manager, and if possible, the crane manufacturer to see where the safest place on the jib would be, and to get and idea of how much space we have. For this project, I'm going to assume the crane's jib is 8 feet wide.
2. Unfold the cardboard boxes – save packing peanuts in poly bags for someone to use, and if necessary, tape several boxes together with duct tape to form a sheet big enough to fit under the cow. Mark off measurements for 8-foot jib width, and trace around the hooves for placement on top of the mounting frame. Cut off excess cardboard, and you should have roughly a 6ft by 8ft template:
3. I wouldn't leave the corners squared exactly like the template. I would make modifications to give a bit more room while rigging the cow.
Also, on the template, mark the placement for drill or torch out holes for wire rope rigging to secure the cow to the top plate. Try to go in line with the front and hind legs.
4. OK, now to find a welder and metal worker from the construction crew and some ¼-inch to ½-inch steel plate for the top and base of the mount and some angled steel for the legs and supports. Here's a side and expanded view:
The base should be about a ½ foot wider on each side of the top plate. You don't want to make it exactly 8ft wide either, since lowering the mount into the jib would be more difficult. Make the legs long enough to place the top of the mount so the top of the mounting plate is about half way to the top of the jib, (about 3 feet). The angled pieces on the leg bases (one on each leg and not shown in the expanded view) are for extra support and are made from the same plate steel used to make the top and base. These are about 1 ½ ft tall and long. The holes drilled or torched out are to run wire rope and turnbuckles to secure the mount to the jib. The long angles running from the top plate at the extremes of the top plate are for extra support of the frame. On the top plate. I would also run pieces of 2-inch angle iron on either side of the hooves (take note on template for placement) to avoid the cow sliding around on the top plate – like bookends.
5. After the mount is complete, I would reinforce the fiberglass cow's legs. I can't think of any way to reinforce from the outside structure, without it being very noticeable. I first wanted to fill the legs with casting resin mixed with polystyrene peanuts collapsed in acetone for an expanded effect (I read somewhere it could work, but I wanted to try it out first, since you'd probably have to over-catalyze to generate enough heat to expand the polystyrene) but with a $20 budget, I wasn't sure I'd have enough, and I'm not going to take the leap that they have casting resin at the construction site. The only way I could think of is to fill the legs with expanding foam. Since it is a large construction site, there just has to be someone spraying foam insulation somewhere. Carefully tip the cow on its side and drill ¼-inch or ½-inch holes in the bottom of the hooves. If they have the expandable foam in an aerosol can, that's great since these have the nice little straws on the end. Fill the legs with foam and wait to set. After expansion, trim off excess foam that has extruded out of the hooves.
6. OK, the mount is built, the cow's legs reinforced – time to mount. Have crane and riggers lift mount into place on second tower crane. Secure mount to jib.
Run heavy wire rope with turnbuckles through the left and right sides of the base mounts. You want to loop the wire rope through the bottom of the jib and tighten the turnbuckles until the mount is secure and doesn't have any wiggle or play.
7. Now time for Super Cow. Crane onto mount, making notice of the hoof placement. You want to run wire rope in line with the front and hind legs, or as close as possible (Super Cow is in mid-stride and my example is not), and through holes in top plate and tighten turnbuckles.
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