Hello, I am in need of some direction or advice. We have built a very simple 1x2 retangle tube 30 inches long that goes from vertical to horizontal. The load on the arm is 250lbs. I prefer to use a rodless acme screw because of space constraints to lift and lower this arm. The problem I am running into is everything I am finding is for very accurate movement. I am thinking more like the design on a screw drive garage door opener. I simply want to lift and lower it 10-20 times a day reliably. Does anybody know of such a screw?