Screw drive garden tractor

[Xfaxman]

I don't think culverts are actually "screws." I believe they are just convoluted, so they would just spin with no forward propulsion.

Some are made this way.

Too slow again, jjsjeff posted while I was looking at google images.

 

[mikehaugen]

Not all culverts have a screw pattern, but I've seen some that do.

Example:
<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=410380"/>

Some are made this way.

<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=410383"/>

<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=410384"/>

Too slow again, jjsjeff posted while I was looking at google images.

Well I stand corrected... in that case, those look like they would work nicely.

 

[Rednic79]

well I started on the screws, what a nightmare...check it out

http://youtu.be/0E7m3U3kuy0

 

[GolfAddict]

Awesome!! :thumbsup:

This project is soooo fun to watch!

 

[Rednic79]

hehe...glad you like it!

 

[GolfAddict]

It sure looks like that sucked. Would it work to slice the ring in multiple pieces, tacking them on in that spiral shape?

 

[Rednic79]

well...the only thing is that they need to be 'twisted' not just angled, so without the leverage of the larger piece it's hard to twist. when I get to the end of one ring, I can barley twist it right until I weld the next ring to it for leverage.

It sure looks like that sucked. Would it work to slice the ring in multiple pieces, tacking them on in that spiral shape?

 

[GolfAddict]

OK, gotcha. So, another question - could you weld the rings together first, or would it just take way too much to stretch it all apart in one piece?

 

[mikehaugen]

Nice job!

A thought on the calculation for the ring... I think you would want to use the circumference of the tube as a starting point. Then add the spacing that you want, which gives you your new circumference. That would come out to about 11.3" I.d.

I'm not sure if that's right either, but it's the formula I came up with a couple days ago when I was thinking about this.

 

[chim]

Well I stand corrected... in that case, those look like they would work nicely.

I'm guessing they wouldn't work very well for more than one reason. The most serious is ou'd need to find righ and left hand culverts. To travel, the pontoons need to rotate in opposite directions. Otherwise, the tractor will travel sideways.