Hi

I need to replace my dryer vent. It's an old house and the existing vent is 3"

I found a 3" vent at Home Depot but when I try to fit it into the hole in the foundation it doesn't fit by just a hair or two!

It's like the previous pipe was placed there before the concrete was poured!

I don't have much in the way of tools. Tried chipping away at the opening (which is not perfectly smooth) with a hammer and a heavy file, which broke. In terms of power tools I have only a drill.

After an hour of that I have several lacerated fingers and have made very little progress.

I just need a fraction of an inch or so. Can someone recommend a tool that would do the job better? Just a heavier hammer and proper chisel?

The vent cap is metal and I can't push it very hard from the outside without denting the thing.

Kinda stuck for doing laundry until I fix this.

Help! :)