Boomilever B/C

TheSquaad
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Re: Boomilever B/C

Postby TheSquaad » October 10th, 2018, 2:56 pm

retired1 wrote:Answer to the question would be to use math. My preference would be to make a scale drawing and measure it.If the tension members are from the hook to the load eye bolt, then I think you have it reversed. But,if you have the angle of attachment to the main portion, then it will always be at a level orientation. The height above the do not exceed line will vary.

Not a problem if you accurately graph it. I like the large quad paper from office depot.

Actually, I put it in my "Model Smart 3 D" computer program and it does all of that for me as well as accurately predict the results for what ever densities I entered into it.


I’d just build it on a testing wall. I made a version where the hook is about 14.8 cm above the bottom of a standing wall, so I can literally just build on top of a table and against the wall.

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Re: Boomilever B/C

Postby OpticsNerd » October 10th, 2018, 5:18 pm

Any tips on how to make the J-Hook contact point strong?

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Re: Boomilever B/C

Postby Unome » October 10th, 2018, 5:36 pm

OpticsNerd wrote:Any tips on how to make the J-Hook contact point strong?

A dowel-shaped piece should suffice. Bass might be useful to avoid compressing the wood from the very high stress. I doubt other orientations provide enough benefit to be worth the cost of damaging wood fibers (e.g. bending).
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Re: Boomilever B/C

Postby retired1 » October 10th, 2018, 6:57 pm

TheSquaad wrote:I’d just build it on a testing wall. I made a version where the hook is about 14.8 cm above the bottom of a standing wall, so I can literally just build on top of a table and against the wall.


If you mean that the boom would touch the table--If I were the ES, I would disqualify your boom.
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Re: Boomilever B/C

Postby dholdgreve » October 11th, 2018, 6:33 am

Cow481 wrote:How would you figure out the length of the tension pieces. The window of length would seem very tight. If you make it to short, the boomilever would sit at a downward angle from the loading block angle and if it was to long, the boomilever would also sit at an upward angle from the loading block.


This will depend on your unique design... How are you attaching at the top? How thick is your mounting block? Will the tension rod extend all the way through it? Where will your tension rod intersect the compression beam? Will it extend all the way past the compression beam?

I agree with Retired... Come up with your design, then draw a scale model, either pencil & paper, or CAD... Then just measure.

I can tell you this much: In 99% of the designs, your tension rods can come from 24" sticks and your compression beams can come from half of a 36" stick for ordering purposes.
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Re: Boomilever B/C

Postby dholdgreve » October 11th, 2018, 6:37 am

retired1 wrote:
TheSquaad wrote:I’d just build it on a testing wall. I made a version where the hook is about 14.8 cm above the bottom of a standing wall, so I can literally just build on top of a table and against the wall.


If you mean that the boom would touch the table--If I were the ES, I would disqualify your boom.


I assume you are talking about using the table only as a temporary support to maintain a 90 degree angle of the compression beams to the wall. Of course this would only work assuming the vertical wall is at a 90 degree angle to the table. (Notice I did not say perfectly vertical, as if the table were not level, the wall should not perfectly vertical, but 90 degrees to the table.)
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Re: Boomilever B/C

Postby DarthBuilder » October 11th, 2018, 2:36 pm

What are some ideas to make my boom stronger near the base or at the base? My booms have always ripped where the base is and everything else is intact.
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Re: Boomilever B/C

Postby Carrot » October 11th, 2018, 6:40 pm

DarthBuilder wrote:What are some ideas to make my boom stronger near the base or at the base? My booms have always ripped where the base is and everything else is intact.


Do you currently have your tension members parallel to the compression members? From what I am planning to do, I'd make the base width small but still keeping enough space for the hook to rest on a horizontal member, almost so it looks like a "V" at the end. Also, what kind of glue are you using for the base?

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Re: Boomilever B/C

Postby Carrot » October 11th, 2018, 6:43 pm

Does anyone know of a way to test the tensile strength of a piece of wood (without using any high-end machinery)? From what I have been doing so far, I have been putting force on a scale and trying to imitate that force on the tension sticks, though I believe that it is nowhere near accurate.

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Re: Boomilever B/C

Postby DarthBuilder » October 11th, 2018, 7:05 pm

Carrot wrote:
DarthBuilder wrote:What are some ideas to make my boom stronger near the base or at the base? My booms have always ripped where the base is and everything else is intact.


Do you currently have your tension members parallel to the compression members? From what I am planning to do, I'd make the base width small but still keeping enough space for the hook to rest on a horizontal member, almost so it looks like a "V" at the end. Also, what kind of glue are you using for the base?



Yeah everything seems to be in place. I use Bob Smith CA glue (purple bottle)
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Re: Boomilever B/C

Postby Carrot » October 12th, 2018, 5:24 am

DarthBuilder wrote:
Carrot wrote:
DarthBuilder wrote:What are some ideas to make my boom stronger near the base or at the base? My booms have always ripped where the base is and everything else is intact.


Do you currently have your tension members parallel to the compression members? From what I am planning to do, I'd make the base width small but still keeping enough space for the hook to rest on a horizontal member, almost so it looks like a "V" at the end. Also, what kind of glue are you using for the base?



Yeah everything seems to be in place. I use Bob Smith CA glue (purple bottle)


I would recommend using a stronger glue just for the base, like a wood gorilla glue for example.

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Re: Boomilever B/C

Postby Cow481 » October 12th, 2018, 5:48 am

How far is where the base would be from the testing wall? My coach hasn’t set up the testing wall and hook so it still looks like a tower or bridge tester and we don’t have practice until saturday. I’m trying to figure out the dimensions of the base and tension members.
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Re: Boomilever B/C

Postby Cow481 » October 13th, 2018, 8:33 am

sorry for double posting but how tall does the testing wall have to be to be legal?
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Re: Boomilever B/C

Postby retired1 » October 13th, 2018, 9:30 am

Per rule 5. a. i. It must be a minimum of 40 cm wide and 30 cm tall.
Per 5.a.iii The hook should be approximately 5.0 cm below the top.

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Re: Boomilever B/C

Postby MadCow2357 » October 14th, 2018, 4:48 pm

Any idea on how thick the base should be? I'm currently accounting for a 1 cm base.
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