PVC Wobbly in goal?

[Eric Reed]

Can anyone who was at the Manchester kickoff tell me if the PVC tended to rise perpendicular from the ground, or did it have a lot of play? We made the field & goals according to spec, and the PVC is very loose in the holes. Left to itself it tips maybe 10 degrees off vertical.

For those building the field, I'd recommend that you buy materials based on the actual plan BOMs, not the BOM that FIRST provided before kickoff.

Eric.

[codeoftherobot]

I was thinking that it is intentionally loose for placement of balls and such. If you noticed at the kickoff that the PVC was loose which allowed for easier capping of the goals. We built ours according to spec but I don't think we had a 10 degree off vertical. Just a thought. I would recommend securing it by placing a stopper if it is too loose.

[tenfour]

AS it says in the plans, the PVC should be dressed to fit. I guess you could wrap it or something?

[kevin.li.rit]

Yep, the PVC shouldn't be to loose, but still easy enough to take out.

[Doug Traster]

That which is called "1-1/2" Schedule 40 PVC pipe" actually has an ID of 1.610" and an OD 1.900" (according to McMaster-Carr). The holes that are specified in the drawing are 1-7/8" which is 1.875" in decimal. This means that if everything were perfect, the PVC would not go into the holes at all. On the drawing for the mobile goal (http://www2.usfirst.org/2004comp/2004WoodFieldElements-MoveableGoal.pdf ) the words "Dress to fit" refer to the holes in the wood. I think they intend that you ream the wood out until the too large PVC fits OK. I don't know why you are experiencing a 10 degree slant or even a little "wobble". Those poles ought to be skin tight. Confession: We have not actually built our goals yet (today, I hope), so maybe I'm missing something.

[Joe Matt]

That which is called "1-1/2" Schedule 40 PVC pipe" actually has an ID of 1.610" and an OD 1.900" (according to McMaster-Carr). The holes that are specified in the drawing are 1-7/8" which is 1.875" in decimal. This means that if everything were perfect, the PVC would not go into the holes at all. On the drawing for the mobile goal (http://www2.usfirst.org/2004comp/2004WoodFieldElements-MoveableGoal.pdf ) the words "Dress to fit" refer to the holes in the wood. I think they intend that you ream the wood out until the too large PVC fits OK. I don't know why you are experiencing a 10 degree slant or even a little "wobble". Those poles ought to be skin tight. Confession: We have not actually built our goals yet (today, I hope), so maybe I'm missing something.
After much testing, we have found that the poles won't bend or move ON THEIR OWN. But balls in the goals, the big ball, and robots can somewhat bend the PVC. Not much, but a little.

Also, I would rebuild your goals. You shouldn't have that much lean to them.

[RabidWombat]

It definitely looked like the pvc was wobbling/bending some. They probably planned it that way to make it easier to cap. Alot of people on our team didn't know that when we were watching the animation, so we thought the robot broke the goal when the pipes bent when it capped it.

[EStokely]

We just completed a small goal. The PVC is Very straight and upright.

However the first pass had us missing the lower hole (poor placement) with the PVC so there was a lot of lean as the PVC had nothing below it to keep it centered. Once that was fixed all was well.

That hole was tight though :-)

[Alfred Thompson]

The pipes in the goals at the Manchester kickoff seemed pretty tight in the holes when I tried them. In other words I pulled on them to see if they'd come right out and they didn't. It would have taken more effort then I wanted to spend to take them out.