Large Twist Drills

I sold some 3 3/4 inch MT6 drills.

I have a 3 5/16 and I've used it. I'm sure this is no where near the largest.

the ones they use to dig the holes to plant telephone poles look like twist drills, or some sort of auger. do they count?

I've seen some at the Caterpillar plant in Aurora, IL that are 3"+ diameter. But they would be metric, because Cat has been metric since the '70s.

No.

The biggest one i owned was 4" with a #5 morse taper.

Best Regards Tom.

Damn. I have and use a 30" one here.

Karl

Wow ... that had to be a case of something that's really, REALLY, expensive new, but whose market is so thin that it goes for pennies on the dollar as surplus.

Bob

at Cat? How bout the 24"shell mills on the dual opposing spindles- Cincincy Horizontal - 60 taper go figure. That is the BIGGEST damn place I've worked at. No shit, 1/2hr to walk from one end to the other.

~g~

Lots of big stuff there. They probably have much larger drill bits, too, but I remember the 3"+ ones as I walked past a line of big radial-arm drills. They produced some impressive chips, too.

Did you work at the Aurora plant? My F-I-L, Glenn McKittrick, was QC Manager of the machine shop. Some "shop."

• cncmillgil :

My dad was a millwright at the (now defunct) Reynolds Aluminum facility in McCook. It was one of (if not the) largest buildings in the state at roughly 4 million square feet.

I went to an open house there in the late 80's, quite amazing. They had a traveling column machine with 5 spindles and a 300 foot long table. The ingot skinner had opposing cutters ~8 feet in diameter. The electric motors for the rolling mills were

My dad has a million stories about that place, was the end of an era when they tore it down.

Twelve inch? I'd like to see the 'drill press' that'll turn that puppy! Or.... maybe not........ ;>)} phil k.

There's a twist-drill manufacturer with their head office in Seoul Korea who has a scaled-up twist drill sculpture in front of their building. Maybe 20-30' high and 3' in diameter? ;-)

Best regards, Spehro Pefhany

This would do up to 4 inch drills.

On Aug 13, 9:42=A0pm, Ignoramus1032

=A0 =A0 =A0 =A0 =A0 =A0Dan

With a 25 hp motor geared down to 8 rpm and a # 6 morse taper, I would think it would be able to use bigger drills. How do you come up with

The same site has another radial arm drill press with a 15 hp motor and a #5 morse taper and says it will drill up to 4.5 in cast iron.

Both of them are too big to go into my basement.

Dan

Typically, the MT shank isn't rated for making a hole in mild steel much larger than about 115% of it's maximum diameter.

That's not a solid rule, but it's somewhat of a standard many go by.

Regards, Joe Agro, Jr. (800) 871-5022 x113

V8013-R

If someone can make it work on a drill press, I'll count that as the winner.

..No Balsa wood drilling either. :)

Regards, Joe Agro, Jr. (800) 871-5022 x113

V8013-R

Would love to see it. What shank does a 12" drill tool have? The largest MT is #7, eh?