Michael Kellough said:You can omit the lower cleat from the fan mount.
It’s lifting the upper cleat off the rail.
If worried about the fan climbing off the rail when spinning you can stick a long wedge above the cleat.
Thanks Michael, good eye! Even though I used spacers for all the cleats, some are not perfectly spaced. I just moved it down one space and the top cleat now bears all the weight. I'll see if I need a spacer when it warms up (it is -15C today and my shop is only 6C, so don't want to turn the fan on).
Here is my latest tool holder. Just a simple shelf for my Festool sandpaper boxes. It has all been living in a tupperware box that I've been tripping over for months. Now it is nice and neat and out from under foot. I can't wait to use up the rigid 3M sanding sponges I've got there and get some more Festool sponges. The Festool ones hold up way longer! I guess you get what you pay for.