Discussion in 'The Garage' started by tecton, Dec 13, 2003.
need a bit to drill a 3inch diameter hole in soft very thing steel
Hole saw. /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
no no no
drill bit /forums/images/graemlins/rotfl.gif
The biggest twist drill bit I ever saw was 2".
You can risk ruining a forstner bit which will cost you around $80. I've got a 3.5" one for doing plumbing. Otherwise you can get a high quality hole saw (Starrett) for around $15 and another $11 for the arbor. I've had pretty good luck with these.
What are you cutting?
There is a tool called a trepanning tool that is used in the machining industy. It is called VAL-CUT trepanning tool made by SPI. They will fit a drill press with a 1/2" shank.
They are hard to find. You need to get them from a good machine tool supplier. The part number you need is 80-001-1
it is 159.00. I use this on my BPT machine. It makes nice custom washers too.
If not a 3" bit, hows about a torch? /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif Seriously though, how about a jig saw, with a circular, scrolling attachment? Or even a sawsall.....
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