Drilling Mild Steel

Hi All,
I need to drill 20 x M10 clearance holes (so 11mm I think) through 12mm
mild steel plate.
No drill press or anything here :-(
Is this doable with a reasonably heavy duty hand drill and some decent
drill bits or would I be wasting my time?
I was thinking to start with a smaller hole (maybe 5 mm) and work up to
the 11mm? Any other advice?
TIA
Reply to
somebody
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Perfectly doable.
You can do it, but it will be time consuming, and your drill will need to be sharpened once or twice. If you have a friend with a drill press, it will be a lot easier.
Starting with a smaller hole will be somewhat easier.
i
Reply to
Ignoramus7040
No. That works. You only need a powerfull hand-drill (above 800 W not too high RPM) good and sharp drills and some time. I would just pre-drill with 5..6 mm and then do the final cut. If you do it in say 1mm steps, the drill will catch and hurt you.
Nick
Reply to
Nick Mueller
It is doable. A small hole will be a big help. It just needs to be a very little bit bigger than the web on the 11 mm drill. Use some oil, any kind is better than none. If you don't have any, consider buying some ATF. I often drill the pilot hole almost all the way thru ( using oil ) and then fill it with oil before drilling the final hole.
Dan
Reply to
dcaster
Why haven't I thought of that? Thanks Dan!
Reply to
Tom Gardner
Gosh, Tom, I thought everybody knew that trick. I've beeb doing that for probably 30 yrs. Maybe we all ought to post our little tips like this for the benefit of all. Bill.
Reply to
lathenut
As others have said, go for it -but- watch out for wrist-breaking, drill-bending grabs as the big drill breaks through the other side (you do know this, right?) Remember to back off and take it very easy when the drill is about to go through.
-- Jeff R.
Reply to
Jeff R.
Backing it up with a piece of wood, at least a 2x4 will help.
Reply to
reply
Not using a too powerful drill will also help, as would using good handles on the drill.
i
Reply to
Ignoramus7040
And try to hold your drill so you can get your arm and the pressure in line with the bit. Don't let the drill wobble or go sideways to break the bit. Keep a good steady pressure with the bit kept cutting and making chips. If it doesn't seem to be making good progress, stop and put in a new bit. If your drill is variable speed, don't run the big drill full speed.
Don Young
Reply to
Don Young
What everyone else said but add in the need for SLOW speed and LOTS of pressure. Try and find a drill that will run happily in the 200 to 500 rpm range. If you can find one with handles on both sides you can set the workpiece on the floor (clamp it to a 2x chunk to keep it from spining), and bear down with full body weight.
I have an olde 1/2" portable drill, 200 rpm, 2 handles on opposite sides. A sharp drill and it will just drive right though your 12mm (/2") plate.
somebody wrote:
Reply to
RoyJ
I have a 450 RPM drill also, yes, they are good for this sort of thing, mine is threaded to accept regular pipe for handles.
i
Reply to
Ignoramus7040
My mentor from MANY years back had a 3/4" drill at 100 rpm or so that he used to drill out boiler tubes from inside the firebox of a steam boiler. Had the pipe threads you mention to attach handles. Picture 2' long handles, a 2" drill, inside a confined firebox, and then binding up the drill as you go through. Not pretty.
Ignoramus7040 wrote:
Reply to
RoyJ
I inherited and still use my father's 1948 made Millers Falls 1/2" drill. Weighs about 15 kg, don't need to press it down! 58 years old and still going. Cannot stall it. I was 10 when he bought it. Alan, in Gosnells, Western Oz. VK6 YAB VKS 737 - W 6174
Reply to
alan200
I got Dads metal one. When it caught hold, wrapped me in a circle and the power cord until I could pull it - trigger off the gear train has power ! - I bought an instant off kind. Gave the old family one with the pipe thread head to a friend and warned him to tie it down or tether it and explained.
He was glad, I was glad.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member
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Reply to
Martin H. Eastburn
May help to place a bit stopping sleeve to avoid breaking through. Then after all holes are drilled almost through you can go back and concentrate on breaking through rather than knowing the right time to shift from muscles to gentleness.
Or you can go in from the back.
MG
Reply to
MG
Had the same thing happen to me once. I had a big assed low rpm drill motor that was 12vt DC. I dont recall the brand, but it was great for doing gate installations etc out in the field. I was in a small space behind a gate operator, drilling into a base casting..and hung the bit.
It wrapped me, the drill and about 30 feet of heavy extension cord up into a nice neat package, before the alligator clips on the truck battery finally pulled off the terminals. I managed to get one hand free and get to my cell to call my wife to come unwrap me. I didn't want to call the office..embaressing....
Gunner
Political Correctness
A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
Reply to
Gunner
On Sun, 26 Nov 2006 20:50:31 GMT, with neither quill nor qualm, Gunner quickly quoth:
I recently watched a Modern Marvels program about steelworkers and their heavy-duty 1" pneumatic impact ratchets. Guys lost hands, arms, and legs from them once they switched from rivets to bolts on big steel.
You've since installed a SWITCH on it, I trust?
----- = Dain Bramaged...but having lots of fun! =
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Reply to
Larry Jaques
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member
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Larry Jaques wrote:
instant off
Switch is turned off. The gear train continues going the motor is high speed and still turning and a 100 or so to 1 means torque.
Sounds like Gunner didn't have a switch or could get his hand off it! Martin
Reply to
Martin H. Eastburn
instant off
The switch was the first thing that got a wrap of wire around it....sigh. Bastard switch..sorta like a hole shooter
Gunner
Political Correctness
A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
Reply to
Gunner

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