I saw a video a while back from some guys that were doing hard drive data recovery. I forget what they used for the clamp but it was something fairly simple they had made, I would never have thought it would be possible but it worked. Of course this was just to recover data from the drive, but if you can get it to work at all, I think there is a reasonable chance it will continue working.
A clean box is not strictly necessary. You want an area that is as clean and dust free as possible, and you want to have the drive open for as little time as possible, but careful use of a can of air duster should be sufficient to clean out any remaining dust just before installing the cover. Once closed up, there is an internal filter in the drive that will pick up just about anything remaining. If you wanted to make one, a cardboard box, plexiglass, packing tape, long rubber gloves, some computer fans and a HEPA filter for a vacuum cleaner could make for an ugly but functional one.
Where you get into trouble is running a drive with the cover off. The lack of a cover disturbs the airflow. Stray gusts interfere with the cushion of air the heads float on and cause them to crash. Particles of dust fly under them and do the same thing. I have opened a few drives before to fix stuck actuators and as long as I resisted the temptation to power it up open, some of them worked for years after that. The couple times I ran a working drive with the cover off, they failed within 20 minutes or so.
A clean box is not strictly necessary. You want an area that is as clean and dust free as possible, and you want to have the drive open for as little time as possible, but careful use of a can of air duster should be sufficient to clean out any remaining dust just before installing the cover. Once closed up, there is an internal filter in the drive that will pick up just about anything remaining. If you wanted to make one, a cardboard box, plexiglass, packing tape, long rubber gloves, some computer fans and a HEPA filter for a vacuum cleaner could make for an ugly but functional one.
Where you get into trouble is running a drive with the cover off. The lack of a cover disturbs the airflow. Stray gusts interfere with the cushion of air the heads float on and cause them to crash. Particles of dust fly under them and do the same thing. I have opened a few drives before to fix stuck actuators and as long as I resisted the temptation to power it up open, some of them worked for years after that. The couple times I ran a working drive with the cover off, they failed within 20 minutes or so.