Screw drive garden tractor

[GolfAddict]

Works great! :cool2:

When you hopped on, I wondered if something would give, but it seemed to take it just fine. Had you braced that left side already after removing the old one?

 

[Chopperhed]

Looking good.

 

[Rednic79]

Works great! :cool2:

When you hopped on, I wondered if something would give, but it seemed to take it just fine. Had you braced that left side already after removing the old one?

No i didn't brace it all up yet...reverse is still sketchy. I need to spend time bracing and double checking before the final tests

 

[Rednic79]

Well, the project is over for now...thanks for all the great comments and help along the way! love this forum, i spend many hours searching through it there is a wealth of knowledge here!
Here is the finished product: https://youtu.be/FlJE8OheKbo

 

[Rednic79]

Well, the project is over for now...thanks for all the great comments and help along the way! love this forum, i spend many hours searching through it there is a wealth of knowledge here!
Here is the finished product: https://youtu.be/FlJE8OheKbo

 

[bcp]

Now you know the weak points when you build your next one.

Anyway, you got to be a screwdriver for a while.

Bruce

 

[bakerg]

Sorry to see it fail after all the hard work you put into it. Hope you find a solution as it was a great project, loved following it as you went.

 

[4570Man]

That was an awesome build. I really want to build one, but making the drive screws big enough to float the machine is the biggest hold up.

 

[Rednic79]

That was an awesome build. I really want to build one, but making the drive screws big enough to float the machine is the biggest hold up.

Yeah i just picked up 2 x 100lb propane tanks for some large screws, to float it would need two very very big ones...

 

[4570Man]

Yeah i just picked up 2 x 100lb propane tanks for some large screws, to float it would need two very very big ones...

Water weighs 8.3 pounds per gallon. If the machines weighs 1000 pounds it will need to displace 120 gallons of water. That might be a lofty goal, but I have seen screw drive vehicles drive on water on YouTube.

 

[4570Man]

If I ever get around to building one I have all of the hydraulics out of a skid steer that was headed to the scrap yard. You might find the needed hydraulics cheap out of a bobcat at a scrap yard.

 

[GolfAddict]

Well, the project is over for now...thanks for all the great comments and help along the way! love this forum, i spend many hours searching through it there is a wealth of knowledge here!
Here is the finished product: https://youtu.be/FlJE8OheKbo

It really worked pretty good, but the machine you had to work with just wasn't robust enough. It sure was a great project to watch though - thanks for sharing it!!

 

[Xfaxman]

Great project, it was fun while it lasted. :thumbsup:

Now you can convert it to hydraulics.

 

[Rednic79]

If I ever get around to building one I have all of the hydraulics out of a skid steer that was headed to the scrap yard. You might find the needed hydraulics cheap out of a bobcat at a scrap yard.

what's that stuff worth ya think?

 

[4570Man]

what's that stuff worth ya think?

My grandpa needed an engine to go in a man lift, and it was a hard to find motor because of width restrictions. He bought a whole bobcat for $1500. We removed the engine, all hydraulics, the almost new tires, and drained the hydraulic fluid (over 10 gallon). Then he sold the rest for scrap.

 

[Rednic79]

hello again....so i've been making some good progress on my "screw drive" garden tractor. (if you wan to check it out go to my youtube channel "rednic79" or not..hehe) anyhow....i need some help and advise. i want to put shear pins on the ends of the new screws where the sprockets attach to the shafts so that in a total jam up situation, the pin breaks instead of my whole machine (again).... does anyone have any thoughts on what size of pin i should use? should i use a bolt? what grade? etc?
thanks!
Nic

 

[CalG]

The shear pin diameter should be 40% of the shaft diameter to be "just" equal in strength. when the pin and the shaft are made from the same strength material.

You can do the math on "grade 8 " bolts through "mystery metal shafting" if you want.

 

[Fallon]

Grade 5 or 8. The higher the grade, the stronger the bolt, but also the more brittle. You want something that will snap cleanly. A grade 1 or 3 will tend to bend & leave you with a jammed twisted bolt. Also, make sure there is smooth bolt shaft being sheered, not threads. Threads are much weaker & less reliable than the solid shaft.

 

[Rednic79]

The shear pin diameter should be 40% of the shaft diameter to be "just" equal in strength. when the pin and the shaft are made from the same strength material.

You can do the math on "grade 8 " bolts through "mystery metal shafting" if you want.

so... you think I should go with 3/8 on a 1" shaft? will that break the bolt in a jam up?

 

[CalG]

It really depends on what you need to protect. Is it the shaft the pin is fitted to that has failed? Or is there a weaker mechanism somewhere down the line?

But a 3/8ths grade 3 (ungraded) would be a safe start to protect the shaft. maybe even start with 5/16ths. If the soft ones shear to easily, it's easy enough to go grade 5.
And if those fail too easily, redrill for the 3/8ths. and step up through.