Unfortunately, the robot is at school. The hook is mounted to the back of the intake tray. Looking at it, it is pretty similar to your own bot Jesse. We have the intake offset so it is flat at the bottom and steep at the top.
There are 4 spaces between the top and bottom bar.
I’m assuming four 393 motors on speed with compound gearing, 1:3 and then 1:5?
edit: Got ninjad, looks like I assumed correctly
Compound gearing is notoriously difficult to build correctly, especially when you’re trying to lift 13 pounds with it. Do you have the seperate ‘stages’ of gearing between seperate verticals, or the same verticals?
ie. does your lift look like this: http://puu.sh/5SjOu.png
or like this?: [http://puu.sh/5SjS2.png
(Apologies for the crude diagrams, my paint skills need improving :))
I have found in the past that the second option, without an extra vertical, results in the lift clicking due to the greater length of unsupported axle when lifting heavy weights. The first option provides better support for the axles meaning the gears are more likely to stay meshed. You also want to make sure that the verticals are as close together as possible. If I recall correctly this is a gap of 2 holes for the lower stage that the arm is not attached to, and a gap of 3 holes for the upper stage that the arm is attached to.
However, I think you might be better off to try build a lift at 1:7 (four 393 motors on torque using 84 tooth gears) if you have time, it will be a lot easier to build and maintain, and should still lift a 13 pound robot fairly easily. Bolting two low strength 84T gears together is fairly standard practice to make a 84T high strength gear.
We had this issue with our robot at Conroe due to our lift drive gear being cantilevered. Once we mounted a 25 hole bar with bearing blocks to the outside to give the drive gear support it solved our problem. Given the performance of 9090C I would certainly listen to Tiger.
To clarify, we ditched the compound gearing and we are currently using a 1:7 gear ratio with HT motors. For our last competition we had 4 motors on the drive and 4 on the lift, but as we are most likely using pneumatics and 2 reservoirs, the robot will be a 1lb and a half heavier at least. Therefore, we want to allot two of the lift motors to the drive so our robot can push/drive better.
We want our catapult to flip up, attack its hook onto the hanging bar, and flip back down, therefore lifting the robot by 4 inches or so (hopefully this will work). We also are seeing whether we can raise our robot with a 1:7 gear ratio with two HT motors and rubber bands probably helping it raise.
We also do have a pinion gear (idler) on either side of the 84 tooth gear We would probably leave it there to prevent axle bending. Thanks for the suggestions though.