# Scissors lift gear ratios

I’m new to building scissor lifts, and I’ve seen talk about different gear ratios.
I have 2 questions:

1. What type of ratio is the best if I have 4 stages and want to get 2 cubes and a skyrise?
2. What is the gear ratio of the purple Chinese robot is this video: https://www.youtube.com/watch?v=-BFRcLRlp1A

If possible, I would like a cad render or a close up picture on how to do a 1:15 gear ratio and a 1:21.

Thanks.

I recommend 1:15 minumum for a 4 stage lift. 1:21 if your lift is heavy or you want more capacity.

Try to keep the gears as close together as possible to prevent twisting shafts. Remember that one motor’s torque cannot twist a shaft, but 2 motors geared down three times create shaft spirals with ease. Try to make sure that none of your shafts are transducing torque that might twist themselves.

There are a lot of things one should know when building a scissor lift in vex, and I am glad that this year’s game is teaching the entire community how to easily and efficiently build the dream lift in VEX.

4 stages, and 2 cubes
Option1
-6 motor torque gearing, 1:7 gear ratio
Option 2
-4 motor high speed gearing, 1:15 gear ratio

“purple Chinese robot is this video”
The gear ratio is 1:21 I think, it’s hard to tell.
Someone maybe correct me on this?

Thanks to both of you, but I have another question.

Do you know how they mounted the motors on the scissor lifts?

I’ve always just put it on the C-Channel, but make sure that both sides of the axle are supported. So you will want some sort of smaller piece of metal and/or standoffs to support the axle on the other side of the gear.

No what I mean is how to mount the second motor on one side of the scissor lift. I’m know how to mount the first motor to the 1:15 gearing that I’m planning to do ( thanks Stanley ), but I’m confused on how I should mount the second motor to the gearing.

Thanks