I need an advice for drilling

i need to do 300 holes on a 5/15" steel plate ( over girders on a bridge). The diameter of these holes is 1 1/2". I'd like to use the
equipment that i have; the combohammer TE-56 from Hilti. This equipment is design to work drilling holes on concrete, but i think I could used it for drill over this steel plate (ASTM -A36) too. The speed of this equipment is 485 RPM. What do you think?
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Carlos wrote:

I think you will have to have arms like Popeye the sailor, and that you will still regret ever starting to do a job like that with a hand held drill.
Rent a mag base drill, preferably one with a power feed.
Then watch the machine work for you, instead of vise versa.
Cheers Trevor Jones
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Yeah, holy Christ. That would be a difficult hole with a moderately sized drill press. Or a milling machine for that matter.
I would think you would have to predrill the hole for web clearance, perhaps 3/8", then drill the 1 1/2" hole.
You could probably do a few without a magnetic base drill, but 300? You're nuts. Your wrists will be ruined
485 RPM sounds fast for that diameter. I expect it would chatter and get hot, reducing useful drill life between sharpening to perhaps a few dozen.
If it were me, I'd want to use a 40 amp plasma cutter and a fixture. Then I'd ream it out to size with a tapered reamer. I'd guess 300 would take about a day.
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Hole saws will work, but your tool speed is a little too high. I recently drilled a a few 1 1/2" holes in 1" plate at 385 rpms, but this is too high a speed, too, for good tool life. Do NOT try to do this in "hand-held" mode!! I guarantee that you will regret it. And, if you can't swim, (the bridge) you may test your life insurance. At a minumum. rig some kind of a 3 or 4 foot bar to the drill, that is connected to an immoveable abject on one end.
I have a whole list of horror stories about people who tried to hand-hold a drill while drilling large holes.
Pete Stanaitis ---------------------------
Carlos wrote:

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A friend of mine started down this path once, and eventually had the holes torch cut. That worked out very well.
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As far as I know the Hilti TE 56 drill is a hammer drill only capable of "hammer and rotate" and "hammer only". As such, it would be totally unacceptable for the task at hand.
As others have said, this sounds like a job for a magnetic base drill with a roto broach bit similar to: http://www.ercolina-usa.com/durabore.htm
(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

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Mine is hammer and drill or drill. Wish it were hammer only as well. For three modes maybe. Then in a pinch I could use it to gouge out with a scoop of hard earth or packed sand..
Such is life. Nice drill - stops when the trigger is let go.
Martin
Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder
DanG wrote:

-
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Carlos wrote:

485 rpm is too fast for this size hole, especially handheld.
Either hire or buy a Rota-Broach type machine.
Tom
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1 1/2" holes with a hand drill!? Make a video, please. :-) If you have to buy a camera, buy a magnetic base drill instead. But this way, we won't have something to laugh. You decide. :-)
Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
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Carlos wrote:

I would get a magnetic drill with a carbide hole saw.
John
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    --What he said, but I'd favor using a Rotabroach and don't forget a good lubricant, too.
--
"Steamboat Ed" Haas : Whatever happened
Hacking the Trailing Edge! : to Pasquale Gumbo?
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Did a registered engineer sign off on this project? You didn't specify any details, but holes like that may dangerously weaken the structure. Just my professional reaction to your proposition. Bugs
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As others have said... Rent a magnetic base drill or something similar that can be fastened down. Use Rotabroach tooling... Hougen makes some of the best. A standard bit will probably not work for you...
Use HSS tooling and run slower. As slow as you can get it to rotate with some sort of coolant if you can. That is a lot of holes and the tooling - although not a fortune - will last longer and treat you and the machine better if run at a lower RPM with coolant.
Not sure if you can use oil in that location due to the water... But an oil-based coolant would be best in this case IMHO.
--


Regards,
Joe Agro, Jr.
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