General Discussion

[jma]

We just finished building the tower base jig. Most people recommend building two sides of the tower on the flat surface first. I built the tower sides using the same dimensions of the jig. Because they leaned in, they were shorter than the jig when I stood them up. Therefore I need to work on the measurment again. My question is should I build all sides using the jig or is it better to built 2 sides on the surface.
Thanks,

[Julian]

Here is a simple jig for attaching the two sides of a tower together. First, the two side frames are built on a flat surface, then the jig is used to hold them upright while side bracings are put in place. We've been using this technique for towers, it works.

@jma: I think most builders will agree that the best method is to build two sides and connect them with cross bracing, rather than to build all four sides. It is much faster and you end up using less material. SLM recommended the jig setup above, which would allow you to do just that.

[Balsa Man]

Here is a simple jig for attaching the two sides of a tower together. First, the two side frames are built on a flat surface, then the jig is used to hold them upright while side bracings are put in place. We've been using this technique for towers, it works.

@jma: I think most builders will agree that the best method is to build two sides and connect them with cross bracing, rather than to build all four sides. It is much faster and you end up using less material. SLM recommended the jig setup above, which would allow you to do just that.

It all depends on how competitive you want to be....
Yes, building two flat sides and joining can work; get you a reasonable tower; be pretty easy to do.
The more precise your jigging (hence the closer to your "design configuration/shape" you can build), the closer you can cut it on wood. If your shape is "off" somewhere, wood will need to be stronger (hence heavier) than it would need to be with "perfect" alignment. A full, 3 dimensional jig will likely get you better precision. With such a jig, you align all the legs, then put in the bracing. The amount of wood is the same; you don't build 4 sides and join them (which would mean doubling the legs).

The other comment I need to add is on the dimensions shown; there are a few issues:
1) the height- what's shown is for last year's 50cm minumum height; this year it's from 40 to 70 - that's easy to adjust.
2) the 1cm square top of tower dimension won't work; rules require clearance for a 3cm wide head of (1/4") eye-bolt- the loop head of a quarter inch eye-bolt will not fit through a 1cm square; if you were to build that way, you'd not be able to load (put in Tier 3)
3) At the dimensions shown, its hard to tell, but you need to make sure at the top of the base/bottom of chimney, the chimney fits inside an 8cm diameter circle (otherwise, you're in Tier 2)

[SLM]

... The other comment I need to add is on the dimensions shown; there are a few issues:
1) the height- what's shown is for last year's 50cm minumum height; this year it's from 40 to 70 - that's easy to adjust.
2) the 1cm square top of tower dimension won't work; rules require clearance for a 3cm wide head of (1/4") eye-bolt- the loop head of a quarter inch eye-bolt will not fit through a 1cm square; if you were to build that way, you'd not be able to load (put in Tier 3)
3) At the dimensions shown, its hard to tell, but you need to make sure at the top of the base/bottom of chimney, the chimney fits inside an 8cm diameter circle (otherwise, you're in Tier 2)

1. Yes, the height needs to be adjusted if a taller tower is to be made.

2. Last year, we did build our towers using a ( 1 cm x 4 cm) opening at the top, and were able to successfully load and test them. Both the chain and the eye-bolt are wider than 1-cm in one direction only, If you turn them 90 degrees, they pass through the narrow rectangular opening.

3. Correct, one needs to make proper adjustment to the shorter distance between the legs to make the tower fit inside the imaginary cylinder.

[jma]

@jma: I think most builders will agree that the best method is to build two sides and connect them with cross bracing, rather than to build all four sides. It is much faster and you end up using less material. SLM recommended the jig setup above, which would allow you to do just that.[/quote]

Thanks Julian, I'm building the square base tower so I couldn't use SLM's jig. I built the 3 dimensional jig from the info recommended by Mr. Joeris. I'm trying to figure out how to upload the picture and how to hi-lite the quotes.
　

[Littleboy]

@jma: I think most builders will agree that the best method is to build two sides and connect them with cross bracing, rather than to build all four sides. It is much faster and you end up using less material. SLM recommended the jig setup above, which would allow you to do just that.

Thanks Julian, I'm building the square base tower so I couldn't use SLM's jig. I built the 3 dimensional jig from the info recommended by Mr. Joeris. I'm trying to figure out how to upload the picture.
　

upload it here http://gallery.scioly.org/categories.ph ... 74f38c73f3

[jma]

upload it here http://gallery.scioly.org/categories.ph ... 74f38c73f3[/quote]

Thanks, Littleboy.

[Julian]

Does anybody remember where to find plans to build the water cooler bottle sand delivering device? We have the test table but we would to build the pouring setup like used at states.

I remember seeing this link float around last year. Is that what you are looking for?

[baker]

Does anybody remember where to find plans to build the water cooler bottle sand delivering device? We have the test table but we would to build the pouring setup like used at states.

I remember seeing this link float around last year. Is that what you are looking for?

Sweeeet, thanks, just what we were looking for... thanks again..

[LKN]

Hopefully building a sand dispenser can be my next big project. Thanks for posting the link.

Here is a revamped design I made over the break of BalsaMan's Testing Rig, back from the bridge building days.
http://gallery.scioly.org/details.php?image_id=3642

It was a little bit difficult to make because I had to make sure that it can accomodate up to 70cm towers. The rig hold up to 50lbs no problem, no slip, and doesn't appear to be contorting at all. Overall, it has been working well. Does anyone have suggestions or ideas to improve the design?