Need help from turret experts
 

I'm also woking on researching and designing a big turret. Any thoughts, advise, examples or tips? I know that 25 has a really really nice one.

Re: Need help from turret experts
 

114 has our old one from 2006 - It's rather well designed and very accurate - albeit perhaps on the heavy side.

Talk to a Rex114 about it.

Re: Need help from turret experts
 

Check out this post by Wayne Cokeley about 25's turret design. In addition, depending on your application (ie, how much of an unbalanced load it has to hold, and how far out) large diameter lazy susan bearings from your local hardware store may work fine.

Re: Need help from turret experts
 

Going in the opposite direction, radio amateurs often use novel mechanisms to rotate large or larger antenna arrays. A goodle search on "moonbounce" or "large antenna array rotator" should turn up some good info.

Some have even used army surplus tank turrets for that purpose.

Like Luke said, it depends on the load and unbalance you need to deal with.

Don

Re: Need help from turret experts
 

Check out out 2006 AimHigh shooter... had a suspended shooter turret, great double-bearing system, was very light (less than 5lbs, can't remember exactly, know the whole superstructure of the robot weighed 15lbs), accuracy of +/-0.5deg.

If you want more info let me know.

-q

Re: Need help from turret experts
 

also, try talking to the martians. They've been building turreted arms for quite some time now.

Re: Need help from turret experts
 

Make sure your gears are strong, especially if your turret is going to take a lot of abuse. At one regional, we stripped off eight teeth on a fourteen tooth gear. :eek:

Titanium? ;)

Re: Need help from turret experts
 

You can read about a lot of great turret designs in FIRST Robots: Behind the Design. Not only are the descriptions more in depth then you would normally find in a chiefdelphi discussion, there are a lot of great pictures as well.

Re: Need help from turret experts
 

696 did a nice one in 06. Won them the Innovation in Control Award. Here's a pic. http://www.chiefdelphi.com/media/photos/23631. It was comprised of 4 rings. Inner and outer, and then an upper and lower of each. Each ring had a 45 degree chamfer milled around it. When placed together, inner, outer, upper, and lower, these chamfers would form a diamond shape. In this groove rode alternating steel and delrin balls. This groove gave us 4 points of contact on the balls, so that the turret could be loaded in any direction (axial, radial) and still rotate buttery smooth. It's large diameter made it quite stable.

Re: Need help from turret experts
 

Especially check out 111's turret design. I've read that write up at least 4 times and my mouth keeps watering.

Re: Need help from turret experts
 

I would suggest checking out 75's Turret

http://www.roboraiders.com/showcase/...turret_idw.PNG

http://www.roboraiders.com/showcase/?page=assy&type=sub

Re: Need help from turret experts
 

Yes, they do take a lot of abuse so make sure they are well-supported/mounted. Our 2006 turret took a lot of abuse and finally snapped at Monty Madness final match. It did not work for a couple matches at IRI also because it had been beaten down so much. The 2004 turret which used a chain was a bit stronger. I'll see if I can dig up a few pictures and post them.

Re: Need help from turret experts
 

Wow that's insanely complicated.

Re: Need help from turret experts
 

In our design this year we used Ultra-High Molecular Weight Polyethylene (UHMW) Disk sandwiched between two 3X3 aluminium box, with a sproket welded to the box and a bolt going tru all to keep it centered. The UHMW provided a very low amount of friction, making it very easy to turn. I will post a pic later to show it a bit more clearly

Re: Need help from turret experts
 

For my money if 12" is large enough - order the $28 lazy susan from McMaster Carr. We used them on the last three years machines and they take a lot of abuse before giving out. for $28 you can't make one any cheaper any better.