Retrofitting hole patters in a metal fan enclosure

Maker Talk
1

Hi Asmbly friends!

I have a home improvement question related to retrofitting a bathroom fan into an existing metal enclosure. The goal is to use the housing that is currently in place to avoid needing to cut out drywall. I haven’t worked with metal enough to have any starting point for a strategy

Despite getting a fan of the same manufacturer, only 1 of the 3 mounting screw holes match up. The question is - how can we add appropriate spacers, and the drill new holes into the existing enclosure so that the fan sits like it should? Bearing in mind that it will have to be done to something already installed in a ceiling.

My initial thought was to drill holes in the housing where then new mounting holes need to be, find a rubber piece that is the same thickness as the little bumps, and then use a sheet metal screw to install. But genuinely no idea if that would hold well enough. Appreciate any and all guidance

  1. what the fan mounting holes look like next to the fan that is being removed
  2. the enclosure we are working with
  3. the enclosure that came with the fan, for illustration of what the bumps look like with slightly better lighting
  4. close up on the mounting holes

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2

Do the existing holes use sheet metal screws? If so, your plan seems like it would hold nearly as good as the original.

Another idea would be to use a flat piece of sheet metal as an adapter plate, if the old and new holes in red are far enough apart.

3

Yeah, your plan seems very sound.

Honestly, if it were me, I’d just use self tapping sheet metal screws and call it a day without spacers. It’ll be hidden by a fan grate that’s held on with a floating wire anyway (if it’s like the one I just replaced, lol).

4

The reason I’m thinking the rubber spacer will be beneficial is because of potential vibration.

Thanks for the tip on the self tapping screws!

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5

Bathroom fan install completed! :tada: Tom used y’all’s suggestions, along with a bit of forceful encouragement with a nail to make a dent for the drill to have a spot for purchase

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