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I need to drill several (15) 3 inch holes in 3/4 Birch Ply. I have a 3" hole saw and can buy a 3" forstner bit but I am wondering which would be the best option. I can cut some of these with a drill press but four or five will be further into the board and the press wont reach so i will have to drill by hand. any thoughts would be great.
Thanks
Router with a template guide.
A forstner bit will be quite difficult to control hand-held, especially one that large. Depending on what you are doing, a hole saw may or may not be clean and accurate enough. Chris offers a good suggestion.
A holesaw on a hand drill mounted to a mobile drill stand? It's still a crude setup, but the drill stand would afford you some control for a cleaner cut and allow you to position it anywhere on your work surface.
2 3/4" hole saw with the center drill advanced at least 1/4". Make a 3" router template. Trace the circle where you need it. Drill form one side with a hole saw, when the tip comes through, flip and come from the other side to avoid a big blow out. Then secure the template with clamps, or tape, or screw it to a long board and clamp this to locate, then flush trim to the line. Its really hard to control a forstner bit that large.
I don't know how the Irwin adjustable auger bit stacks up against one of the older ones - like my grandfather had 50 years ago, but, my grandfather's and an old hand brace could churn out 3" holes a lot faster and easier than a hole saw & electric drill.
Don't think that will work well in 3/4" ply. My uncle used those expansion bits to drill for door knobs in doors but in ply quality of hole will be questionable in my mind. He also drilled from both sides to prevent blow out.Quote:
Originally Posted by Rich Engelhardt
Router with a 3/4" pattern bit: top bearing. AFTER roughing out the hole with a jig saw.
Use a hole saw, or forstner bit or whatever to make a pattern: a 2-3/4" hole in something - oak perhaps: make sure the inside surface is nice and smooth, and that the piece of wood is large enough to allow the router to travel freely, and still be clamped securely to the work.
Us a compass to draw a 2-3/4" circle on the work piece centered on the desired hole location. Use a a jig saw to hog out the bulk of the waste. Then place the jig accurately and clamp it down. Then use the router/pattern bit to remove the rest of the waste and you'll wind up with a nice clean hole.
I've done it several times. I use a DeWalt 625 router. It's a bit heavy, but it does a beautiful job.
where are you located maybe someone with a cnc could do them for you. would only take about 10 minutes to do
Hmmmm, lots of good suggestion but…..if you already have a 3" hole saw, why not try that first? If it's a decent quality, it should yield decent results. If the results aren't acceptable, then go to plan B.
good luck,
JeffD
Drill the 3" hole in a piece of scrap on the drill press with your Forstner bit (= good hole). Clamp that piece of scrap over the place you want your hole and drill it again with the Fostner bit, (using the guide you just made). Even with a hand held drill you should get good results. Make sure you back it up before drilling completely through...
OOOOHHHH ... +1 on that. Don't even try it with a 3"Quote:
Originally Posted by Steve Baumgartner