More on drill bits over 5/8"

I didn't see the original post, but i did see a lot of responses. Here's mine.
Like others, I had accumulated a bunch of misc. bits over 5/8" and then
a guy gave me a 5 gallon pail full of bits from about 13/16 to 2 1/2". So far, I have turned the shanks on some of those to use when I need a big hole. 1 3/8" is the biggest one I have done this to so far. I run it in my old vert mill at 350 rpm because it won't go any slower. But it works.
Kids and neighbors bring me projects that need big holes. Tractors strip out threads and need the holes to be drilled out and retapped bigger. I have gotten tired of boring holes out to 3/4" or so and then boring all the rest of the way. I even use hole saws up to 1 1/2" or so to bore holes in 1" thick steel.
Anyway, I bought an ENCO Import set of 17/31 to 1" S&D bits (all have 1/2" shanks) a few years ago and I'm glad I did it. The bits aren't the best in the world, but they work and I always have that needed 1/64 under bit to use for an accurate hole that is going to be reamed or bored to size. If and when I need a high quality bit for a specific taks, I buy that size and keep it separate.
Having these larger bits simply expands one's horizon for projects.
BTW, I am considering turning the shanks of some of the 1 1/2" to 2"+ bits, too. For these, I will reduce the back rake from the original 8 or 12 degrees down to 2 or 4 degrees, less if needed, so they won't dig in when used in my underpowered equipment. That may even force me to put a VFD on the mill.
Of course the coolest way yet to make a big hole is to put the part of the Bridgeport EZ-trak at noght school and mill it out in one programmed operation (they won't let us use the REAL CNC stuff.
Pete Stanaitis ------------------
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I feel kind of bad now about owning a wimpy drill press.
i

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I acquired some free boxes of large MT4 drill bits and reamers for use on our press at work. It really beats using hole saws in the thick stuff.
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Also it really helps if you grind 3 flats on the shank to match the 3 jaws of the chuck; much less slipping at high torque.
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Yes, that works well if you can grind the flats accurately. I use collets to hold these bits in the mill.
Pete Stanaitis ----------------
Nick Hull wrote:

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You can grind them REAL accurate by chucking them on the drill diameter in the lathe chuck and using the lathe indexing bull gear and grind the shank with a tool post grinder.

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