The circular saw drill bit wasn't catching on the drywall, so I just drilled a circle of holes and used the hand cutting tool to open up a 6" hole in the interior garage wall.
Then I repeated it with the interior insulation. The metal vent connector pipe fit perfectly, and is now butting up against the limestone siding.
And that's as far as I can go because I am still waiting for a Hammer Drill I ordered from Amazon on recommendation of my machine engineer son-in-law Michael. Hope to have it by the weekend. If it gets here, and its complete (I had to return one yesterday because it came with the drill bits missing from the box), I will start trying to drill some holes ... using Michael's recommendations on grip and force ... stay tuned. The hard part is what comes next.



... angling the strikes at the edges, I found the limestone easily gave way ... eventually a had a (somewhat) circular hole, but 'good enough' ... as you can see the basic assembly is done ... I will need to chisel some stone edges to push it even to the wall, then use spray filler for the gaps ... a long way to go yet! 





