Drilling big hole in metal

[abunaitoo]

I need to drill a few 5/8 and 3/4 holes in 1/4 and 1/2 metal.
Largest usable bit I have is 1/2.
I have a set of large bits, but they just don't drill metal.
When I got them, they were suppose to be able to drill metal.
Any suggestions on what would work????
Probably just a one time use.

[JWFilips]

I have found some cheap Drill bits in the past on e-bay They don't last long but can get "a job" done for a low price

[Hossfly]

I like those step bits but maybe not for that thick especially 1/2’’ thick, you’ll need a proper bit for that.

[rancher1913]

go to a rental yard and get a mag drill and the special drill bits for large holes, they are kind of like hole saws but use a carbide tip.

[JSnover]

go to a rental yard and get a mag drill and the special drill bits for large holes, they are kind of like hole saws but use a carbide tip.
That will be the easiest way if you don't have a drill press or a mill. It's possible to use a hand drill but the magnetic drill will save wear on your wrists and elbows when the bit breaks through the offside.

[country gent]

A properly sharpened drill bit slower speeds and lots of oil to lubricate and cool the cutting edges. The bigger the drill the slower it needs to turn. With practice and drill gage twist drills can be sharpened on a bench grinder. If hand drilling a small pilot drill hole helps a lot. Look at the drill point on you will see each sides cutting edge and a small line between them, This is a dead point that doesn't cut and needs to be forced in to the material. A small hole the same dia or slightly bigger relieves this force allowing the drill to cut easier.

[skeettx]

Can you post a picture of the big bits that you have that will not cut metal?

Have you seen these?

https://www.amazon.com/Cobalt-Silver-Deming-Drill-Reduced/dp/B019TUPLJG/ref=asc_df_B019TUPLJG/?tag=hyprod-20&linkCode=df0&hvadid=309869401414&hvpos=1o1&hvnetw=g&hvrand=15644364411098315466&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9028456&hvtargid=pla-570094393805&psc=1&tag=&ref=&adgrpid=63364097444&hvpone=&hvptwo=&hvadid=309869401414&hvpos=1o1&hvnetw=g&hvrand=15644364411098315466&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9028456&hvtargid=pla-570094393805

Mike

p.s. and of course you know to start the hole with a small bit and work up in stages and use
lost of cutting fluid?

[Gewehr-Guy]

I use hole saws a lot, but I'm not sure they make one in 5/8. It takes a good drill to handle a 3/4 bit, lot of drills now have poor gears, some are even plastic.

[Three44s]

A fluted tapered reamer and a 1/2” electric drill geared for 500 rpm (Harbor Frieght for the drill would suffice).

If you don’t mind a bit of taper on the 5/8” hole a 3/4” reamer might cover both hole sizes you desire.

The tip of the tapered reamer should start in your 1/2” holes you can already make.

Using regular drill bits by hand is a great way to get really hurt. Too grabby.

Three44s

[Iron369]

That big and that thick I would use a good hole saw for sure. With a corded drill with a clutch.

[Iron369]

I drill 1” holes in thick steel poles almost daily with hole saws.

[Iron369]

Just go slow and use cutting lubricant

[bob208]

what are you powering them with ? the harbor-fright drill presses do not turn slow enough. in fact I don't think any of the small drill presses out there turn slow enough. I use my vertical mill. another thing that would work would be a old post drill. if you were close enough I could sharpen your drill bits.

I would start small and work up in size.

[Three44s]

The drill I mentioned from HF is a geared 1/2” electric hand drill running 550 rpm no load. It is cheap but I have done a lot with one at our farm shop. I run a 5/8” car reamer easily with it in steel thicker than the OP has a need for.

I have no doubt that my drill would also handle a 3/4 reamer as well.

On older US made geared 1/2” hand held drills I have had fluted tapered reamers on the order of 1 1/8” dia. I would not take a ordinary twist drill bit for such applications any way shape or form.

When we have no choice but to use a twist bit of any substance we remove the handle and screw in a substitute stub that we can add a cheater pipe to and have a second person on the end of. I’ll gladly buy another drill rather than suffer through or pay for someone’s broken arm.

Three44s

[lightman]

They make hole saws that size. Probably the cheapest option if you have to buy something for this project.

[Three44s]

Respectfully I can not imagine cutting a series of holes in steel 1/4 to 1/2” thick with a hole saw, they may be cheaper but I have cut enough holes in dashes for gages in gauge thickness metal to know that it would take multiple saws to equal a twist bit, much less the superior car reamer.

Picture this: The 5/8” reamer I am referring to was first bought to use to finnish a rebuild of a Brillion cultipacker. We had two layers of steel, both 5/16” thick with oblong 7/16” holes from wear to drill through with a hand drill. We took the 5/8” car reamer and over sized to clean holes without incident through both layers simultaneously. We installed new 5/8” bolts at the multiple locations and saved an expensive tillage tool from being junked out.

As I recall my 5/8” reamer cost about $55. It will out last many resharpenings of a twist drill and has not needed resharpening itself yet and has been used on many projects since the Brillion project.

Three44s

[Winger Ed.]

Hole saws with lots of oil should work for you.

[wl620]

Do you have or have access to a cutting torch? I use mine for stuff like this all the time, even though I own a drill press and an extensive drill bit collection, while not as precise as a drill bit it will get the job done and save some time in the process. With some practice and a little grinder/file work you can cut good round holes. I can’t believe I’m the first to suggest this, maybe I’ve been doing it wrong?

[Winger Ed.]

maybe I’ve been doing it wrong?
If it works, it isn't wrong. Not as precise perhaps, but not wrong either.

[Ianagos]

If you don’t have a drill press capable I’d say start with a small starter hole say 1/4 the follow it with your 5/8 bit nice and slow. Take your time stop and add cutting oil. I have and probably will many more times burnt the corners right off my larger drill bits with a hand drill.

If it’s something shipable small or maybe could be more complex let me know I have a cnc shop and I’m willing to help a member out here or there. That goes for any others aswell but I must warn you I don’t have much time.

The cnc mill makes any size hole look easy although that is just aluminum.

https://uploads.tapatalk-cdn.com/20190110/8921164b41c3580db23b1f12d1504dde.jpg

[Alstep]

First piece of advise, WEAR SAFETY GLASSES!

For the situation you describe, I would recommend a hole saw. Use lots of cutting oil and back out to relieve chips often with compressed air. If you don't relieve the chips, the saw will bind up in the hole and break. A hand drill or drill press should be OK for a hole saw for up to 1". Don't go over 250 to 350 RPM. The bigger the hole, the slower the RPM. You're going to be awhile getting through 1/2" of metal.

A better alternative would be a heavy duty magnetic base drill setup.

With regular drill bits, don't go over 1/2" with a hand drill, the torque will rip the drill right out of your grip. Harbor freight drill presses don't cut the mustard either. For bigger holes, I drill in increments till I reach the size I need. For that, a Bridgeport mill with the work well clamped is a minimum setup.

I give this advise after a lifetime working as a machinist in the metal working trades. Work safe & good luck.

[Jeff Michel]

Take it to a machine shop and pay them. Less stress, probably less money spent and more predicable results. I have a fairly complete machine shop but I don't have a big burn table or a water jet cutter. The man does down the road, I let him do the heavy accurate cutting and while he does that, I work on other aspect of the project. FWIW, I agree that doing it by hand isn't probably the best course safety wise, it takes a pretty good man to handle the torque from a 1/2 inch drill and a big bit. Good luck and be safe.

[abunaitoo]

I have a drill press.
That's how i drilled the 1/2 holes.
I'll have to see how slow i can get it to go.
The reamer idea sounds good.
I'll have to look for some.
I have a metal hole saw set, but it's not that great with thick metal.
The one that has carbide cutters would be great, but hard to find here.
Also have a Unibit set. Might see if that would work.
Going to home depot tomorrow to see what the have.
I've always wanted one of those magnet drill press.
So expensive.
Have a torch set, but holes have to be round.
I'm not that good.

[GregLaROCHE]

I’ve drilled 5/8” holes in 1/2” SS with a hand drill. Not fun, but it can be done. Make sure your bits are sharpened correctly. Even if they are new, if they came from China they may not be right. This a good video explaining how drill bits work and how to sharpen them correctly. If the quality of your drill bits isn’t up to it, I sugget a machine shop or carbide hole saw.

https://youtu.be/r8oORR6jyh8

[Traffer]

I have a drill press.
That's how i drilled the 1/2 holes.
I'll have to see how slow i can get it to go.
The reamer idea sounds good.
I'll have to look for some.
I have a metal hole saw set, but it's not that great with thick metal.
The one that has carbide cutters would be great, but hard to find here.
Also have a Unibit set. Might see if that would work.
Going to home depot tomorrow to see what the have.
I've always wanted one of those magnet drill press.
So expensive.
Have a torch set, but holes have to be round.
I'm not that good.

I got a set of Silver and Deming Drill bits from Harbor Freight for $28.. 9/16 in., 5/8 in., 11/16 in., 3/4 in., 13/16 in., 7/8 in., 15/16 in., 1 in. They cost me $28 on sale. If you start with a smaller drill and work up to your size holes and use cutting oil they will cut the holes for you. I have used them many times to drill deep into steel, I used then to hollow out 1" cold rolled steel to 13/16" then tap to 7/8 14 to make holders for standard reloading dies, I used a cheap HF table top drill press the first time, Went from 1/4" hole right to the 13/16"...it took a long time... so I started doing the bigger and bigger hole thing...
When you do it leave the belt kind of loose and clamp down the work, you don't want it to start spinning on you. Use safety glasses, leather gloves and feed slowly...you may have to sharpen your bits a couple times while going through if they get knarled up on you. The kind of lose belt keeps the bit from spinning in the chuck, belt will slip first.
Good luck

[rancher1913]

https://www.ohiopowertool.com/p-8478-hougen-1-12-x-1-depth-of-cut-hss-rotabroach-annular-cutter-12148.aspx?gclid=EAIaIQobChMIicWO6Izj3wIV14KzCh3Kl wiKEAQYBCABEgJVgvD_BwE

this is the type of bit that works really good for holes in thicker metal. a rental yard should have everything you need.

[RU shooter]

As another member said find a small fabrication or machine shop . I have a waterjet that would make quick work out if it but the shipping to and from where your at would be costly

[EDG]

I have drilled maybe a million holes in 1" plate using radial arm drill press.
I would take your work to a machine shop.
You should center punch where you want the holes and let a machinist drill them. Both pieces of metal you are drilling are not very thick for such a large drill and will tend to grab when exiting the back side.

[JSnover]

Do you have or have access to a cutting torch? I use mine for stuff like this all the time, even though I own a drill press and an extensive drill bit collection, while not as precise as a drill bit it will get the job done and save some time in the process. With some practice and a little grinder/file work you can cut good round holes. I can’t believe I’m the first to suggest this, maybe I’ve been doing it wrong?

When I worked at the Juniata locomotive shop an oxy-acetylene torch was the preferred 'drill' for any hole over 1/2"

[Ole Joe Clarke]

Take your piece of material and go to the nearest small machine shop. Some of them will help out an individual, and they have the proper drill bits, drill presses and/or milling machine to do the job. You will save time and the hassle of trying to do it with the wrong tools. The cost to you will probably be well worth it.

Have a blessed day,

Leon

[country gent]

The difference between the home drill presses and industrial grade gear head drill presses is like night and day. We would drill scrap exhaust holes in die shoes up to 3" in the big drill press at work. This machine was gear head and lowest rpm was 12 rpm. I believe the fasted was around 800 rpm. Power feed. 10 HP motor. Forward and reverse. You had to securely clamp everything down to the table this machine didn't stall out and holding the part by hand would suck you right into it. With the right pilot hole this machine would drill a 3" hole the depth of the drill. When the feed was engaged it cut very cleanly and gave a good chip curl. This machine had a #5 morse taper in the spindle. It would do bigger as well but 3" was the biggest drill we had.

When drilling holes a solid set up, correct pilot hole, good cutting oil. Correct speeds and feeds goes along ways. When drilling roll shirt sleeves up, safety glasses, a ball cap or something to contain hair and no loose clothing. A drill press spindle will grab a few hairs then more and finish when your scalped. same with gloves or loose clothing it grabs and sucks you in.

[Conditor22]

How many and how accurate do the holes need to be?

I'm no machinist, I would drill them out to 1/2 then enlarge to 5/8 or 3/4 so the big bits aren't having to hog out as much.

[JonB_in_Glencoe]

I got a set of Silver and Deming Drill bits from Harbor Freight for $28.. 9/16 in., 5/8 in., 11/16 in., 3/4 in., 13/16 in., 7/8 in., 15/16 in., 1 in. They cost me $28 on sale. If you start with a smaller drill and work up to your size holes and use cutting oil they will cut the holes for you. I have used them many times to drill ...

>>>SNIP
I have the same set of bits, and have drilled some large holes in 3/8" thick steel plate...just follow the directions that Traffer layed out.

[GregLaROCHE]

I’m not a machinist, but have had a lot of life experience drilling holes in steel. Mostly with under powered drill motors and presses. I’ve found cobalt drills work better than HSS. If you have a pilot hole and the drill has enough powder, you can go right through in one pass. If the equipment is not the best, that is when working up in sizes comes into play.

[CastingFool]

I don't know how large the pieces you need to drill, but if possible, make sure your pieces are well clamped down

[popper]

Be sure to bolt that sucker down when drilling, whatever you use.

[country gent]

One thing we did when using a hole saw to help it cut clean. We layed out the hole center then with dividers the actual edge of the hole and 4 -8 small holes 3/16-1/4" so that hole edge was on the edge of the actual hole. With these holes the saw could clear chips easier these holes allowed chips to drop out. they also gave a place to pry / grip when pilling the slug out. Never cared for the finish, size or the way a hole saw cuts when working in metal.

[country gent]

If you cant clamp / bolt piece down a well placed bolt thru the table slots for it to bear against will help with it wanting to spin

[abunaitoo]

https://www.ohiopowertool.com/p-8478-hougen-1-12-x-1-depth-of-cut-hss-rotabroach-annular-cutter-12148.aspx?gclid=EAIaIQobChMIicWO6Izj3wIV14KzCh3Kl wiKEAQYBCABEgJVgvD_BwE

this is the type of bit that works really good for holes in thicker metal. a rental yard should have everything you need.

Was looking at bits like this.
I'll probably look for a set later.
If I can find them for cheap.

[abunaitoo]

Went to home depot and got two drill bits.
I'l move the belt on the drill press to the slowest setting.
Lots of cutting oil.
1/2" hole already drilled for the 5/8" hole.
We'll see how it goes.

[country gent]

With a 1/2" pilot hole feed slow and very easy. Your only cutting .060 on a side and it will want to grab and try to thread itself in. Make sure set up is very solid. In the drill press if it has a spindle lock set it to a snug spindle movement

[rancher1913]

we always used plain old water for cooling as we drilled. I was astounded the first time I seen the boss use water that way but it worked good and was easy to clean up.

[Traffer]

we always used plain old water for cooling as we drilled. I was astounded the first time I seen the boss use water that way but it worked good and was easy to clean up.

That is interesting. They recommend water for lube with the little diamond charged dremel type tools and wheels that I get from eBay-China. It is amazing how well water works with these diamond burrs. Far Far better than oil. I have tried it on the lathe also with same great results.
There is one BIG caveat... RUST. It is hard to get all the water out of machines. Nightmare waiting to happen.

[Traffer]

Your drill press probably only goes down to about 300 rpm or so. That is scary fast for drilling steel with big bits. It will chatter and bounce and be a wild ride. Get a good grip on the feed handle and hold it tight. Feed as slow as physically possible and use oil. Don't get scared off by the violence of the project...IT WILL CUT eventually. My first attempt at drilling steel with big bits (going 3" deep into cold rolled steel) was quite an ordeal. I kept trying to modify the bits to take a smaller cut ... it's really hard when the darn thing is spinning so fast. I use a lathe now and slow it down to about 40 rpm with a razor sharp bit. My little lathe still bogs down and trips the breaker. So I now use the "sneak up on the proper size" technique of using progressively bigger bits.

[lightman]

Early on in my life I found a bargain on several different size reamers. These were tapered with the last 1 inch or so being straight. They chuck up in a drill and require less power and muscle than a drill bit. They are brittle and can be broken pretty easily but they make a neat hole with less effort. I have no idea what they would cost but might be worth checking on for a guy that builds lots of stuff.

As far as drill presses go, I wish I had a better one than my old Craftsman. Several years ago I wired a machine shop for a well drilling buddy. He bought out a machine shop and moved all of the equipment. Some of it was huge! One lathe was about 70 feet long and looked like a locomotive. One drill press would handle 48 inch wide material and the column was about 12 inches in diameter. It would reverse and had automatic feed. A nice milling machine fairly makes me drool!

[country gent]

One thing old timers and some shops did with the home drill presses was to replace the step pulleys with a different set of them to slow them down to a useable speed range. They are normally off the shelf pulleys and can be purchased reasonably. Getting the spindle lowest speed to 75-100 rpm from the normal 300-400 rpm can be a big plus. For the added cost of 2 pulleys and possibly a v belt you get a more useable machine longer drill life and more versatility. You don't give up a lot since if the higher speeds are needed the old pulleys and belt can e installed, 1-2 set screws in each pulley.

On the old converted flat belt machines I have also seen 3 and 4 speed transmissions used between motor and drive belt to give speed range changes. Transmissions from older lawnmowers, garden tractors or cars were used here. This gave 3 forward speeds and a reverse on the drill press or machine in addition to the belt drive.

[dogmower]

how precise do the holes need to be? if not, why not just use a torch?

[Three44s]

Reamers breaking like that makes me wonder about how they were manufactured or abused in their former lives. Besides the reamers I have bought (1/2” and 5/8”) my father has acquired perhaps a half dozen large ones with Morse taper drive. I think one has a short chunk missing in one flute and that still does not put it out of service.

My 5/8” car reamer cost right at 55$, nothing to sneeze at but for the value I would do it again in a heart beat. Whether I am using a drill press or my HF 1/2” drill that is geared to 550 rpm free spin I find this reamer to be superior to any other hole enlargement scheme I have tried or seen tried.

I have a old heavy duty drill that needs a new trigger and cord. I should take it and get it rebuilt I know I will spend a tidy sum by doing so. The HF drill contrary to what a lot of folks have felt about it has been very good to me. I have worked to capacity many times but for the cost if I just used it as an overgrown 3/8” it would likely last a long time.

Three44s

[country gent]

We used the 1/2" drill motors for a lot of smaller holes since the speeds of them were closer to what was needed

[Three44s]

how precise do the holes need to be? if not, why not just use a torch?


Trust me, I am no stranger to the “old gas wrench”.

What I get is quick chilled steel (hardened) and having to dig out a die grinder and run a carbide bur to make the to hole more “holy”. I never get what I really want, just a get by.

When I get my tools out and center punch things accurately, start with a good light, small sharp drill bit and step up sizes, don’t hurry, I get something I don’t have to make excuses for and use a bunch of flat washers on.

A year and half ago I fell into a 8800# radial arm drill at an auction. I have not set it up yet (shop space be darned) but when I got it my father asked what was wrong with the cutting torch?

I said well it’s like this .........

Best regards

[Conditor22]

Not knowing how hard the steel is, a shop could punch the holes (I think the machine is called a metal worker)

[Traffer]

One thing old timers and some shops did with the home drill presses was to replace the step pulleys with a different set of them to slow them down to a useable speed range. They are normally off the shelf pulleys and can be purchased reasonably. Getting the spindle lowest speed to 75-100 rpm from the normal 300-400 rpm can be a big plus. For the added cost of 2 pulleys and possibly a v belt you get a more useable machine longer drill life and more versatility. You don't give up a lot since if the higher speeds are needed the old pulleys and belt can e installed, 1-2 set screws in each pulley.

On the old converted flat belt machines I have also seen 3 and 4 speed transmissions used between motor and drive belt to give speed range changes. Transmissions from older lawnmowers, garden tractors or cars were used here. This gave 3 forward speeds and a reverse on the drill press or machine in addition to the belt drive.

Yes, I have been collecting pulleys to eventually build a drill press with the capabilities that I would desire. One of the things I have considered for my little HF benchtop press is a third step pulley. I have two identical HF drill presses... one of which I am planning on converting to an extended tail stock for my lathe. I wont need the pulley so I could use that to gain a x4 speeds by installing it with an additional belt. I believe there is even a convenient place on the press to install it. That would get me under 100 RPM's ...Ideally I would like to get it down to about 10 RPM's.

[JSnover]

That is interesting. They recommend water for lube with the little diamond charged dremel type tools and wheels that I get from eBay-China. It is amazing how well water works with these diamond burrs. Far Far better than oil. I have tried it on the lathe also with same great results.
There is one BIG caveat... RUST. It is hard to get all the water out of machines. Nightmare waiting to happen.
I don't use diamond burrs but every machinist in my shop is issued one of these kits. Coolant is mixed in a 55 gallon drum and you can use any container you like as a reservoir. If it's mixed too light you can get rust but if the instructions are followed and your machine gets normal care - wipe it down and oil it after you finish - you won't have rust (at least we haven't). As with most everything else, your mileage may vary...
https://koolmist.com/lite-duty-coolant-system

[country gent]

That's how our tool room was we had several 55 gallon drums of coolants with hand pumps on them. Water soluble mixed for the mills and mixed for the grinders ( surface, Id OD and Blanchard), black oil, dielectric fluid. With these in a rack on the wall were the labels In our shop ( ISO 9001 and haz mat regs) containers had to be labeled as to what was in them.
Single serving soup cans went for a premium for use with the black oil LOL

[starmac]

I have had to drill lots of 5/8, 3/4 and 1 inch holes in truck frames and thick steel. Where I can I generally use a mag drill and annual cutters, but there are many holes that room doesn't allow it, for those I use a 3/8 bit and the appropiate reamer. These reamers set me back 50 to 60 bucks a piece, but are worth every penny, as far as I am concerned. I have an old slow turning KILL you if you aren't careful but have just used my cordless drill quite a bit too.

[mozeppa]

ii made over 3000 one and a half inch diameter disks from 5/16" thick sheet steel strap ...hard stuff

did it with cutting oil , drill press and YES!....only 3 MILWAUKEE BI-METAL HOLE SAWS. just don't force it.

i've cut 4" holes in 3/4" solid steel plate the same way......yes people ....they WILL work.

[Alan in Vermont]

https://www.ohiopowertool.com/p-8478-hougen-1-12-x-1-depth-of-cut-hss-rotabroach-annular-cutter-12148.aspx?gclid=EAIaIQobChMIicWO6Izj3wIV14KzCh3Kl wiKEAQYBCABEgJVgvD_BwE

this is the type of bit that works really good for holes in thicker metal. a rental yard should have everything you need.

I spent several years in a couple structural steel fab shops where Hougen Drills were a fact of life. Using their drill motors, mag bases & cutters, under perfect conditions they claimed a 1" hole in 1¼" plate(going from memory here those numbers may be reversed) in 10 seconds. I never had a machined plate to test that claim but I don't doubt it at all.

Any how, for a while I was doing a fair amount of fab work here at home. I have Hougen cutters for thin material, up to 1/4" in sixes from 5/16 to 2" with the appropriate drive arbors so I can run them in the drill press or a hand drill. They also have arbors that have MT shanks for drill presses & mills, with or without coolant feeds. I found cutters from 7/16 to 1 1/16, most of them in 2" cutting length on Ebay for decent prices. I bought a #2 MT arbor to use in my china clone of the Delta 12 or 14 inch drill press. I rarely work in anything greater than 1/2" stock and I can borrow a Hougen mag base if I have to take the drill to the work.

Another tool for really close marking hole locations is an optical center punch, https://www.amazon.com/Grizzly-H5781-Optica-Length-Punch/dp/B00012YFIA/ref=sr_1_3?ie=UTF8&qid=1547406076&sr=8-3&keywords=optical+center+punch If you're doing layout with scribed lines you set the body of this tool roughly over the marked point. Drop in the spotter lens and move the tool body into the crosshairs in the lens are over your marks. Then, hold the tool body firmly in place, remove the lens and replace it with the center punch. One light tap sets a small dimple which you deepen with a regular centerpunch & hammer.

[abunaitoo]

Got it done.:bigsmyl2:
Wasn't to bad.
Moved the belt to the slowest speed, but I think it's still to fast.
Not sure how fast it's spinning.
Couldn't count fast enough :veryconfu
I hope I don't have to drill to many big holes like this.
Project should be done tomorrow.[smilie=w: