ECN Forum
Posted By: Rabbit Hole Saw - 07/19/06 02:03 PM
In search of a deep hole saw at least 5". In 4 1/2" diameter. Anybody?
Posted By: SolarPowered Re: Hole Saw - 07/19/06 02:56 PM
Dynatech (www.dynatech-diamond.com) 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 [Linked Image] )

[This message has been edited by SolarPowered (edited 07-19-2006).]
Posted By: Peter Re: Hole Saw - 07/20/06 01:16 AM
Rabbit,
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.
~Peter
Posted By: e57 Re: Hole Saw - 07/20/06 04:25 AM
If steel, a cutting stick on an arc welder....

Wood, a sharp self-feed bit (Up to 4-5/8")
[Linked Image from coastaltool.com]

Concrete, call someone who does core-sawing, and add them to your bid +>20% mark-up. [Linked Image] Cheaper for single holes this way, but not if you nedd 100...
Posted By: Rabbit Re: Hole Saw - 07/20/06 03:49 PM
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!
Posted By: PE&Master Re: Hole Saw - 07/30/06 12:28 AM
A sawzall and a couple of long blades. Not pretty but functional.
Posted By: dougwells Re: Hole Saw - 07/30/06 06:27 PM
How about an arbor extension http://www.coastaltool.com/cgi-bin/...t+hspl7478ff6f136f+1154381098#extensions

[This message has been edited by dougwells (edited 07-30-2006).]
Posted By: Trumpy Re: Hole Saw - 07/30/06 11:48 PM
I've always used the arbor extensions that Doug linked to, for anything deeper than a standard holesaw.
Makes life a lot easier. [Linked Image]
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