Hand made air filter system

[Todd Hyman]

I have a used 2 speed furnace squirrel-cage fan that I want to use for a air fitler system and I have a question about whether to mount it horizontal or vertical (the blade axis that is)? If I mount it vertically, I can use a 16x25 filter and there will be about 2-3 inches of clearance between the top and bottom of the box and the fan. If I mount if horizontally, I will have to use 20x20 filters and there will be 3-4 inches of clarance between the side of the box and the fan. To mount the fan (this is one heavy fan) I will probably mount the fan by using longer srews (3) that mount the motor to the blade shaft. The fan does have a metal flange on the exhaust side, but it is only 1/2 inch wide and I don't think that it would hold the weight of the fan. What to you guys think. Thanks for you assistance.

[Tom Andersen]

If your fan has ball bearings and not plain bearings, you should be able to mount it in any angle.

[Todd Hyman]

If your fan has ball bearings and not plain bearings, you should be able to mount it in any angle.

How can you tell the difference?

[Tom Andersen]

Could you post a few pics of the fan, with close-up of the bearing side?