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#67823 - 07/19/06 07:03 AM Hole Saw
Rabbit Offline

Registered: 01/01/02
Posts: 61
Loc: Kingsport Tennessee
In search of a deep hole saw at least 5". In 4 1/2" diameter. Anybody?

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#67824 - 07/19/06 07:56 AM Re: Hole Saw
SolarPowered Offline

Registered: 07/05/04
Posts: 615
Loc: Palo Alto, CA, USA
Dynatech ( has dry-cutting core drills in 4" and 5", and wet-cutting bits in 4-1/2", among other sizes.

(Edited in a vein attempt to get the link to come up as a link )

[This message has been edited by SolarPowered (edited 07-19-2006).]

#67825 - 07/19/06 06:16 PM Re: Hole Saw
Peter Offline

Registered: 06/08/04
Posts: 93
Loc: San Diego
This depends on the material you need a 4 1/2" diameter hole through.
If wood, then use a regular 4 1/2" bit and drill as deep as possible [about 2"]. Then chisel out the waste. Drill again. Repeat chiseling. If possible access from other side, use a long 1/4" aircraft extension bit to extend your pilot hole all the way through and use the hole saw from the other side. This will create a nice exit hole.
If concrete, layout a 5" circle around your point. Along the circumference, drill a series of 1/4" hole with a SDS rotary hammer about 1/2" apart. Then enlarge these holes to 3/8". Then to 1/2" Eventually the holes will wander into each other. Then attack the remaining webs between them with a chisel point and the rotary hammer -- such as the Bosch Bulldog -- set in "hammer only" position.
If steel: What? 5" of solid steel. Did a structural engineer OK this? Perhaps a plasma cutter or a big blue wrench. Consuly Hougens for a rotary broach. Maybe a trepan.

#67826 - 07/19/06 09:25 PM Re: Hole Saw
e57 Offline

Registered: 05/27/03
Posts: 2837
Loc: S.F.,CA USA
If steel, a cutting stick on an arc welder....

Wood, a sharp self-feed bit (Up to 4-5/8")

Concrete, call someone who does core-sawing, and add them to your bid +>20% mark-up. Cheaper for single holes this way, but not if you nedd 100...
Mark Heller
"Well - I oughta....." -Jackie Gleason

#67827 - 07/20/06 08:49 AM Re: Hole Saw
Rabbit Offline

Registered: 01/01/02
Posts: 61
Loc: Kingsport Tennessee
It is a piece of steel channel under a rooftop unit. Rubber roof, so burning is out. I'm not sure of all the details as it is another PM's project. I told him if it existed the ECN guys would know. Will probably wind up making one. Thanks for all the help!

#67828 - 07/29/06 05:28 PM Re: Hole Saw
PE&Master Offline

Registered: 02/25/06
Posts: 138
Loc: TX, USA
A sawzall and a couple of long blades. Not pretty but functional.

#67829 - 07/30/06 11:27 AM Re: Hole Saw
dougwells Offline


Registered: 05/03/03
Posts: 1226
Loc: kamloops BC Canada
How about an arbor extension

[This message has been edited by dougwells (edited 07-30-2006).]

#67830 - 07/30/06 04:48 PM Re: Hole Saw
Trumpy Offline


Registered: 07/05/02
Posts: 8532
Loc: SI,New Zealand
I've always used the arbor extensions that Doug linked to, for anything deeper than a standard holesaw.
Makes life a lot easier.
Let's face it, these days if you're not young, you're old - Red Green grin


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