I'm building a power lift for a sewing machine. It needs to lift and hold firmly a 35lb sewing machine. It will be cycled only rarely but it will have to hold the load indefinitely. Speed is not an issue, in fact it needs to be rather slow. Would an actuator of the type here at Openbulds be appropriate? I suppose it would need linear bearings as well or perhaps an actuator at each end of the platform. There is one off the shelf unit built specifically for sewing machines that sells for $650.
Yes but only if you use a considerably less aggressive screw. The weight of the machine would overpower the supplied TR8x8 the instant the steppers were shut off and the machine would drop. I would suggest dropping back to a 5/16-18 all-thread rod or a TR8x2. You will also need thrust bearings at the top to properly support the vertical screws.
Constant force springs would allow you to do it without even motorizing. Example - Source - Another Source