lots of holes in stainless pipe

i have to cut @400 .875 holes in 1-1/2 schedule 10 s.s. pipe. most are at 90 degrees on the centerline. some of the holes pass thru both sides, others only one

i have at my disposal

milling machine

motivation to build a dedicated machine as this will be ongoing , then can do the odd angles at the mill

Reply to
Chris Henry
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Penetrator twist drills

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Insert endmill/drill in the mill
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You do have coolant, preferably through drill coolant, right?

Same distance between holes? A simple spring loaded plunger into the last hole drilled on an adjustable holder works a treat for spacing.

Big question is..how long is the pipe? and whats the tolerance in parallelism in total length?

Gunner

Reply to
Gunner

Sounds like an application for Hougen Rotabroaches.

Reply to
Ernie Leimkuhler

+1 on that. Jancy is another brand. Do a search for annular cutters, there may be more sources out there.

Amazing cutters. I recently used a small mag drill to drill around 150 holes horizontally through the 1/2" thick web of some standing I-beams. One cutter did them all, little bit of cutting oil, no sweat. Hardest part was climbing ladder with mag drill on shoulder.

Reply to
BillM

I have used rotabroaches on a mag drill, and on a milling machine. They work enormously better on a mag drill, because all you have to do to eject the slug is to retract the quill fully, whereas if you e.g. use a 3/4" collet to hold one in a Bridgeport spindle, you will have to stop the spindle each time and pry out the razor-sharp slug by hand. And, sadly, the pipe would be much more easily workheld on the mill table than the mag drill. But yes, rotabroaches would cut the material well.

Grant

Reply to
Grant Erwin

"Grant Erwin" wrote in message news:dkFHj.148$ta2.111@trndny05... . They

Hmmm----didn't think of that. My use of them in a mill has been limited to square/rectangular tubing, and the slug usually falls out. I wonder how difficult it would be to set up a tubular drawbar with an eject pin running through the middle?

Bill

Reply to
BillM

I believe i am on the verge of building a custom mandrel and using a c frame punch, the pipes are @ 10 feet and there are 42 .875 holes in each.

the shortcut for rotabroaching in the mill is to use the pin hole and afeneder washer to bolt a spring ( i have a old soft die spring) to the inside of the cutter

BillM wrote:

Reply to
Chris Henry

How would this work? I can see running a 1/4-20" bolt through the pin hole and into the bore of the spring ID, but surely you wouldn't have it go all the way through the spring so what contacted the workpiece first would be the bolt head, would you?

Grant Erwin

Reply to
Grant Erwin

nope you use the fender washer and trap the first turn or so, depending on the spring. ( the turns closest to the top of the cutter. but you could do it your way as well. you just need a little bit of pressure to eject the slug.

Reply to
Chris Henry

42.875 holes - be kind of interesting to watch you drill that last part of a hole :-)

Bruce-in-Bangkok (correct email address for reply)

Reply to
Bruce in Bangkok

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