Drilling big holes without harming yourself

Ever wind yourself up in the electric drill when drilling a big (over 1/2") hole in metal? I sure did when I had to drill out some 5/8"
holes out to 3/4" in the underside of my broken tractor.
I wrote to HSM in 1996 and asked for ideas. I got a lot of feedback so Here's a new page on my website that summarizes the responses I got:
http://www.spaco.org/Blacksmithing/Bighole/Bighole.htm
Pete Stanaitis ------------------
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Some decent ideas, but not too many that would be useful for your actual problem of opening up an existing 5/8" to 3/4"... If your existing was 3/8" or something similar, the job is actually easier IMHO.
--


Regards,
Joe Agro, Jr.
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Yeah, enlarging 5/8 to 3/4 in a thick piece of steel ought to spin you up in the air like a maple wing, once the lips on the drill bit grab tight. <g>
-- Ed Huntress

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Unless of course you have feed control to make sure it doesn't dig in...
But that's not likely with a hand drill, mag drill, etc.
An AutoDrill has that option, but is slightly out of most people's league when doing non-production work. :)
--


Regards,
Joe Agro, Jr.
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(WARNING! Thinly disguised promotion above! <ggg>)
See, Joe, you can tell I once did PR for a living. I tossed you a softball, right over the plate.
Wouldn't you like to have your own professional PR guy on retainer? d8-)
-- Ed Huntress

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Thinly disguised?!? That was blatant and purpose-driven. :):)

Swing batter, batter!

Would love one. ...some day.
Regards, Joe Agro, Jr. (800) 871-5022 01.908.542.0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com Production Tapping: http://Production-Tapping-Equipment.com / Flagship Site: http://www.Drill-N-Tap.com VIDEOS:
http://www.youtube.com/user/AutoDrill

V8013-R
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Inside tip: Don't go for the retainer. Do it project-by-project. Otherwise, the PR person, if he/she is faithful about doing all they can for you and what you're paying them, will wind up making a complete pest of himself/herself (and of you) with the magazines. Then they'll stop answering your calls. d8-)
-- Ed Huntress
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A negative rake 3/4 drill from china solves that problem.<G>
A tool & die maker would use a stub length 3/4 counter bore with a 5/8 pilot installed to open the hole up to 3/4.
Best Regards Tom.
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I like that one!
Pete Stanaitis ------------------------------

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Joe AutoDrill wrote:

Well my solution would probably not make it BUT. I would make a simple step drill (or buy a large one and grind it down) the first step would be 5/8" with a taper out to 3/4". Then set up my Cole drill and drill the hole(s) Simple and easy with a lathe.
--
Steve W.

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Hmmm. A method that I don't see listed--use a square drive chuck on an impact wrench. Mine is a Jacobs 64-J9. Grind the drill for zero rake on the face and have at it. Used to use this method for opening up egg shaped mounting holes on hydraulic and air cylinders, and for taking out shear pin holes on sprocket drives to the next larger size.
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I was just out the other day and watched a crew putting some new gusset plates on the el train bridge. They were running a bridge reamer through the holes with an impact wrench. One handed operation, overhead. Brrrrrrap, you got a neat 1" hole.
Paul K. Dickman

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spaco wrote:

Use a grinder?
--
Paul Hovnanian mailto: snipped-for-privacy@Hovnanian.com
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Use a hole saw. Hole saw a 2 pieces of hardwood with a 3/4" hole saw and save the 5/8" OD slugs. Stack the slugs on the pilot drill and use them as a pilot in the 5/8" hole. Drill slowly with lube.
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NPS thread ( Not NPT ) a nipple and a coupling .
about 1.25 inch . machine this to fit on end of
your hand held electric drill motor .
Machine the coupler to accept loose 3/16" grade 25 balls
just like a BallBearing chucks does . these allow
the coupler to rotate on the nose of drill motor .
Now power the male threaded nipple . turn it with a
Harbor Freight 18VDC cordless ( cut the case off it ,
it gets real small and handy , its only about 1.5" Diam' )
Coupler has a chain sproket , 18VDC cordless has
a smaller #40 chain sprocket .
start drilling , pull trigger on 18VDC cordless to advance
the bit toward the work .
18VDC cordless is on the side of the big drill motor , 18VDC drives
a tiny chain that drives the coupler , thru a large reduction of sprockets
( Coupler upper end attached to
drill motor nose but on loose balls , in a race )
couplers bottom side is threaded to nipple
( nipples bottom is a FOOT against workpiece )
Like a MicroStop countersink , the nipple and coupler lower the
drill motor toward the workpiece
Nothing lighter , more compact .
If i were less busy , id sell these .
I will build airplanes . 400 H.P. takeoff power .
pusher props . twin 70" blades .
3 Yamaha or Honda motorcyle engines , with variable intake cam timimg .
at cruise , they make less than 8 H.P. , but outstanding economy .
for the variable intake cam timimng . Atkinson Cycle !
RAM tuning works fine at 7500 RPM , but you must "tune"
the intakes for the reduced flow !
At high HP , you switch in a bigger diam' set of intake tubes .
On takeoff ( 5 minutes ) , they each produce over a
hundred real H.P. ** at good fuel econo , .
yet at cruise fuel economy is good , intake valves are retarded
closing to make much lower effective compression ratio
for the Atkison cycle ,
Some Engineers wrongly say , aircraft engines need to run
slow to produce HP , at good economy .
But Japaneese created a light weight motor , capable of
over 100 H.P. at much lower fuel consumption , than
any of the much larger competitors , and with
even better economy , at cruise !
You cant match it .. Not Continental , Not Lycoming ,
not Subaru , Not Bombadier . Not even
ZOCHE ! 8 cylinder diesel that has amazing power to wt and costs more than a new 1 Ton Chevy P.U. !
Perfect Diesel ! Germany ! But costs too much . www.Zoche.com
If you build airframes with 2024T3 and rivets , it would take
forever ..
But if you use old bicycle technology . Tubes brazed into lugs .
You can inexpensively build an airframe in 10% of the time
with NO precise measurements nor blueprints .
You can make the lugs as you go , cut the tubes , braze
tubes in progressively ..
But once a lug is ready to braze , you cant add anything
to the lug , except by more brazing ( which is strong , but
a kludge )
Airframe is "consistant' from motor mounts , to landing gear .
Its all the same construction . Unlike sheet aluminum
where you need to :
...bring the loads to a stress point : the landing gear wheels and motor mounts .
If you put too much steel in the lugs , grind it off , fair it
with a 1/4" Die Grinder ! until it looks right .
DIY lugs are hammered from 1/8" steel plate and formed and
MIG'ed and hammered again , til they look right .
MIG tiny lugs and flanges on top , for attaching the cheap aluminum
fairing pieces .
sand down and polish the lugs , so they're
photo graphable , the lathe them in a tiny 7 by 10 lathe
with face plate , to bore out the holes , perfect fit
for the 1.5" steel tude you CRS ( cold rolled yourself to 100kips )
Wings fold forward . Motors can add traction to landing gear
so you can get in the 10 O'Clock news .
Landing gear has 4 main wheels ( free , for cross wind landing )
2 smaller , aft to keep props from digging up the runway .
Props blades are DIY alum , cold forged ( like the inexpensive
crank arms on your mountain bike )
I defy you to build a lighter , stronger , lower cost , in less time .. cargo plane that lifts 3000 lbs of payload ..
And you can kit it !
try kitting a alum' skinned airplane . Thats why they sell
Carbon-Fiber airframes !
Engines have allways been the big cost ... engines are Nikasil plated ( not iron liners ), never need over pistons/rings ...
BTW STOP using 10-30 wt oil w/ detergent !!
I dont want a plastic monomer to burn and fail in my engine .. I want the acids and sludge to NOT circulate around my motor . I dont want to emulsify anything .... I want the NON-oil to separate and fall to the bottom . I DONT want a clean shiny bottom surface on my oil pan !
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