wa2crk wrote:stopping and popping should not be heard. They could indicate that something is binding and then releasing. Try removing the gas pressure tube and check to see if the popping stops. If it does very closely check the castings of the lift assist for cracks especially in the welds. The gas strut puts a lot of stress on the components. Also check to see if the clamps that hold the way and bench tubes to the end castings are tight and there is no movement in the associated parts. After this if you still have the popping noise check with Shopsmith to see if the gas strut is under any kind of warranty.
The popping noise (one pop on the way down) has stopped when I move the carriage down. But the resistance going going down is still there and at about 23-25 degrees, the headstock carriage will still stop. Extra force downward will push it through the resistance The end castings on the bench tubes are tight - a couple of bolts were snug and those were tightened more. I bought the Lift Assist three years ago, so it is out of warranty now.
I'll try an auto parts store to see if it has something similar.
Thanks everyone for your tips.