Koopi 4.25 Hole Saw with Heavy Duty Arbor, 38mm Depth Bi-Metal 4 1/4 inch Hole Cutter for Easily Drilling Wood, Plastic, Plywood, Drywall, Thin Metal (108mm)

I bought this to drill 6 holes in my ceiling to install LED lights. It is a custom home from the early 70s, so the ceiling drywall has about an 1/8-3/16 of plaster finish. By the third hole, the teeth were 75% gone and it would not cut. I had to cut the remaining three holes with a key hole saw - that saw had no problem at all cutting the plaster-coated drywall. Im sure the plaster layer is more abrasive than plain drywall, but this bit is supposed to be able to cut through metal. I cant imagine this bit would hold up for very long in anything other than plain drywall. If thats how it was advertised, Id be fine with the outcome, but they represent this as a cuts anything bit, and that is very far from reality.

I used this to drill one hole through steel siding, osb and some spray foam insulation in order to vent a bathroom basement exhaust fan. It worked perfect for my single hole. I ran it backwards at the beginning of the cut so it didn’t catch and I had a nice clean hole in the end.

Is easy to use does a great job. Thanks.

Gave to someone

Cut through fibreglass easily

everything

I needed the 6 3/8 hole saw to install a duct for a range hood through four kitchen cabinets. The Koopi is a heavy duty unit, accent on heavy, and the one I received seems round and well balanced. Learn-by-doing experience: I found that my 20 volt Dewalt drill is adequate for this saw, but I wouldnt want to use anything smaller. The saw is unwieldy to use, especially in the top of a wall cabinet where keeping the saw parallel to the cutting surface is a challenge. Using the drills clutch to keep the drill from spinning dangerously when the teeth bind in the wood was the only way I could manage it. This way when the saws position isnt just right the drill clutch engages; when the hole saw is correctly placed the teeth do their job fairly well. It did take some time to cut each 1/2 inch deep hole--and my high end Dewalt drill got very hot--but the saw worked well. Ive cut seven plywood holes so far and the saws teeth dont seem too worn yet. This is a pretty good tool for something I only need for one job.

This was purchased to drill a vent hole into the side of a dryer. With a little cutting oil, the holesaw cut right through the outter and the inner panels. Now Im not saying that this tool would cut the same holes all day long, all I am saying is the tool did what I needed done, which was a 4 hole in the side of the ol;d bags new dryer. Pressure off. Well worth the price.

Only used it once so far, to cut through the roof, but it is heavy duty, cuts well and easy to use.

At a large hardware store this will cost you over $30. Here it was a fraction of the cost without compromising the quality. I was installing a laundry exhaust and had to cut through aluminum siding asphalt siding and plywood for a total of 3 inch thickness wall. I did have to do it in increments because of the depth of the hole saw but that is to be expected.