[zakthor]

I put a 6" hole through the wall of my 50 year old house to hook up portable air conditioner.

All went well except for using the 6" hole saw with arbor bit.

I used an old dewalt 1/2" corded hand drill with a side handle.

Drilled a pilot hole, then started on the inside. Drywall was fine, then insulation. Once 7" deep I hit the first 3/8" plywood, then a second 3/8" plywood, then 1/2" of vertical cedar. I did the final outer layer of shingles from the outside.

The plywood was so difficult to drill. Very hard to keep the hole saw flat against the plywood and it would bind in the groove causing drill to buck. Once the blade was through some of the plywood it was binding really bad and impossible to hold steady.

Best approach seemed to be letting drill spin up with lowest power, lightly contact and hold as steady as possible until it bound. Usually it bound in less than 10 seconds.

Took me about 90 minutes to make the hole but some of that was working with key saw to get pieces out.

I imagine some tripod thing to make a horizontal drill press would be great but I don't have that. What is the trick? Build a jig? I got a great hole but the process sucked.

Would have been more comfortable to use a clutched driver so drill didn't try and kill me every time the bit stopped.