The Meticulous Z-Axis

I weighed my sled. It is 18 pounds. Hmmmmm…your is almost double the weight of mine. So far, I have not added weight to it but am now wondering if I should add some. Has anyone determined what/if there is a min. weight for the sled?

Be aware with the CoG thing because as you raise the CoG, the chain (at the sled) moves further away from the table thus causing side tension on the gear at the motor. This caused the chain to skip or wrap around the sprocket. I know this because I had this issue and the only way I solved it was to remove the stretchy string and replace it with counter weights.

Here is a picture of my sled setup.