Re: [PSUBS-MAILIST] Lead Screw

In a message dated 5/27/2004 11:04:39 AM Central Daylight Time, ojaibees@ojai.net writes:

Doug, can I get a stainless screw that is not a real fine thread? I think the fine thread could have a tendency to get stiff from debris

Yes, if you google for "lead screw" or "ball screw" you'll find all types. www.mcmaster.com stocks several varieties too. But if your planning on using it in a wet environment I'm not sure a lead screw is your best solution. I don't think it would take much sand to jam up any lead screw. The ones I have seen are always well lubricated and shielded when in unclean environments. I have never seen one used submerged. They do allow you to finely position a load, but being within 1/32" is not that important right? Someone suggested chain, and that is what I plan to use too. The chain runs a loop from the drive sprocket to an idler sprocket and back. I purchased some used stainless steel roller chain of eBay for a song. But instead of relying only on the chain for the weight, you can use it to move a lead weight. The down side is safety. If a lead screw drive fails the weight is less likely to move, but if a chain breaks then both the weight and the chain are going to head down hill. If anyone has experience with using "lead screws" in ocean like environments it would be helpful to hear your thoughts.