Unless you are going to start manufacturing scissors lifts you will probably be better off buying a scissors lift from one of the many companies that are in that business. By time you re-invent the scissors lift you will probably have more time and money in building one than if you purchased one. There is also the issue of getting one built and finding out what you didn't anticipate. A failure at the wrong time can kill somebody. You can buy one and let the manufacturer assume the liability. I recently purchased some lifts from Autoquip and customized them to suit my needs.