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I am attempting to flush mount three guest battery switches in a sheet of 1/2 in starboard. Problem is I need a 5 1/8 hole saw. Looked around the web and dont see that size anywhere..any ideas?

scribe it with a compass and cut it with a jig saw.....clean up with a half round file...

One thought would be to use a rotary cut tool, dremmel or roto-zip or router, even a jig-saw would work. Use a compas or the battery switch to trace the line of the hole free hand the cut. If you can do this on the bench rather than installed it's not too bad. Hopefully there's a flange on the switch that will hide an irregular cut.

br,
JohnD

John,

The easiest way is to use a 5" hole saw and then unch up the diameter with a 1 1/2" drum sander on your electric drill motor. If you wobble the hole saw a bit during the initial cut, the hole will be a tad bigger than 5" leaving only about 3/64" of radius to sand away, getting you to your desired diameter.



Br,

Patrick

I have a rotozip, but a ryobi brand one, it came with a neat circle cutting attachment.

I'm going with Randall's idea, a roto-zip can get away from you before you know it. NOT a precision cutting tool. Go with the jigsaw!

well....i have an adjustable hole saw....blade on bar kinda deal....but you should be able to do it fine with a jig saw or patricks method....not brain surgury

They made a tool for that too....

Thanks for the help...Randel does that adjustabe hole saw thing work? I was checking it out on the web when searching for hole saws. Seemed like a good idea

John,

If you are refering to a Fly Cutter, they are a great tool, but not ment for use in a hand drill.... Drill press only tool, and even then they can be dangerous. But, no doubt about it, a great hole cutter.

even Stevie Wonder could cut a perfect circle with this thing and not have it get away from him

Pat,


The tool I looked was called a hole pro..( holepro.com) kinda looks like the same thing you posted...Thanks, John

I've got a fly cutter (adjustable) and it works fine on wood, plastic, or soft metal....the trick is to run it very slow - say no more than 60-75 rpm and keep the blade razor sharp. Works best in a drill press with the work clamped tight.

UV

John,

I've seen the HolePro and it ain't worth the hefty price they ask. The General brand Fly Cutters are usually under $15, available from most hardware stores and place like Home Dildo & Low's. They're almost bullet proof. The weak link is the hex key set screws which are small and round out after much use.

Br,

Patrick

Technically it is s Trepanning tool. I have used them and they will work OK in a drillpress at slow speed, as UV said.

I have a special arbor that I use with hole saws that are 1/8 under sized.

Stuck it in a vise and beat it with a hammer so it wobbles. The end result is a perfect 1/8 oversize hole of the hole saw diameter.

Precision tool making right there.

Rawleigh - you musta made that word up for another 12 days of Christmas deal???? BTW, my fly cutter is indeed a General, very sturdy, made in the USA. I bought it at a gararge sale about 30 years ago for a buck, NIB. Another yard sale bought a gallon paint can full of stainless set screws, all sizes for a buck.

UV

Damed good idea Brother Man...

One note, while I'm at it: Those big hole saws, above 4", can be real wrist breakers when they first start cutting through. Especially if using a 1/2" drive drill motor. When that saw grabs to a suden stop, the torque has to go somewhere & you're it!

Yes. Use a drill with a side handle.

Side handles is fer wusses...

when we did a Bayhead it originally had teak covering boards, when we eliminated them we had to build the gunwale up, so in total the gunwale ended up close to 2" thick, drilling for a water fill I sent the milwaukee drill sideways which swung around and proceeded to smack me right on the chin.

All I kept thinking about was how lucky I was not to fall off the ladder, and how lucky I was that the side windows were not yet intalled because I would have went right through it.

best stuck tool i ever saw was a guy with a LARGE jack hammer held sideways from a steel beam by a chain. he was blasting a hole through a 12 '' thick concrete wall with a 16 inch stone chisel. the blade got stuck when it went all the way through. tttttuuuuurrrrrrnnnnnn iiiiiitttttt oooooofffffffffffffffffffffff.!!!!

Randall,
Blowing snot bubbles on that one!
John

For UV:

http://en.wikipedia.org/wiki/Trepanation

John,
I took a different tack.
I got a bit slightly larger than the diameter of the switches. Cut the holes and mounted them centered in the larger holes (the screw-hole mounts are wider) which gave me air around the switches to cool them and to cool all the electronics behind the switches. Made a very interesting and functional application.