So I am making a stand for my tubing bender, and need to drill 3/4 inch holes through a 1/2" steel plate. any hints? I'll drilled plenty of holes through plenty of things, but I don't want to spend a whole day and have to buy $100 in drill bits. Any hints would be appreciated.
Drilling large holes thought thick plate?
- Thread starter GMBBS
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E.rodz
Well-known member
3/4 holes are not that big so theres no problem.drill some pilot holes say about 1/4 then step them up to say 7/16 then slow your speed to a crawl use some cutting oil penatration oil works well to firm down presure and slow and steady speed.nothing to it.you can torch them out if there just for anchor bolts.use a pilot hole for that also to prevent blowback in your face.good luck.
If it's not hardened steel, that won't be hard at all.
It'll help a lot to have a low-rpm drill and some oil. Harbor Freight's 0-550 rpm drill lists at $55, but is often on sale for $40.
I bought one on impulse, and have been surprised at how often I use it. A regular-speed drill will toast your bits as fast as you can load 'em.
I'm about to do some similar holes in my inch-thick bench, but my thinking is to try to come up with an intermediate plate of some sort, so that I can have one set of three holes in the bench top, and then a few different options for a lever-type bender, a roll bender, a vise, or anything else I come up with down the line that I want to anchor to the bench. The intermediate plate can have as many holes as I need, and will save me from having to keep perforating the main bench.
It'll help a lot to have a low-rpm drill and some oil. Harbor Freight's 0-550 rpm drill lists at $55, but is often on sale for $40.
I bought one on impulse, and have been surprised at how often I use it. A regular-speed drill will toast your bits as fast as you can load 'em.
I'm about to do some similar holes in my inch-thick bench, but my thinking is to try to come up with an intermediate plate of some sort, so that I can have one set of three holes in the bench top, and then a few different options for a lever-type bender, a roll bender, a vise, or anything else I come up with down the line that I want to anchor to the bench. The intermediate plate can have as many holes as I need, and will save me from having to keep perforating the main bench.
OccupantRJ
Well-known member
Safest simple simon way is with a hole saw, clamp it to a table for the drilling, with the hole's position overhanging the top. If you are going to drill it with 3/4 drill bit in a hand drill, you need one that the side handle can be removed, and a piece of 1/2" pipe about 3 feet long used in it's place. One person runs the drill, another holds the drill from spinning. If a drill press is used, please clamp the plate to the table very firmly. A co-worker's friend lost a finger when a piece of plate spun into the column, trapping his finger. I consider plate drilling one of the more dangerous operations in a shop for an inexperienced individual. Most think they can stand on the plate and do the job. Lessons will be learned.
rsanter
Well-known member
3/4....easy
lots of oil and slow RPM with steady pressure
you should see a constant flow of chips
bob
lots of oil and slow RPM with steady pressure
you should see a constant flow of chips
bob
nissan_crawler
Well-known member
if you want them to be fairly true, use a hole saw, if it's not a big deal, use a drill bit. Either way is no big deal. I drilled 20 holes through 3/4" plate with one 5/8" holesaw.
sberry
Banned
Yes, the hole saw is the way to fly for one off projects of this type, I use a battery drill, sometimes even water but usually a few drops of Tap Magic or Rapid Tap. A few drops every 1/8 of thickness. I have drilled the 3/8 in as little as 35 seconds but those 3/4 thru 2 half inch green plates took about 5 minutes a piece with break, done in place. I recall it took maybe half an hour to drill 4 sets of holes and one battery change.
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OccupantRJ
Well-known member
Air blowing at low pressure does a good job on cast iron when using a hole saw, I like to drill horizontally when I can, to let the chips clear, even when using fluids for cutting steel.
sberry
Banned
Yes, Morse, Lenox, Rigid from HD work. One of my buds has a 1 3/4, carbide, said the cut over 600 holes with it. The ones, 1 1/8 you see in the pic were on their 30th or so. You can ruin one until you get the right feel for it, enough pressure and slow enough to keep it from burning, clear the chips or as was said drilling horizontal works although I like clamped to the bench where I can lean on it. On some level I consider the saws a consumable item, kind of like a sawzall blade.
Here we clamp a plate over existing hole and are going to enlarge it. Done in place on the machine.
Here we clamp a plate over existing hole and are going to enlarge it. Done in place on the machine.
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nissan_crawler
Well-known member
I have 3-4 year old lenox holesaws with probably over 100 holes on several of them. Rigid ones...2-3 holes and they start shredding teeth for some reason.
Well lubed lenox ones seem to go and go.
Well lubed lenox ones seem to go and go.
OccupantRJ
Well-known member
Metals like those in the hole saws are one of the things that are getting harder and more expensive to get for American manufacturers. A very few years ago, you just ordered the metals like brass, bronze and copper from fairly local sources, but now some of their warehouses have downsized to basically material transfer docks, with these metals coming from, guess where?, with 3 month lead times. Prices are going out of sight, with price increases each order.
fordcragar
Well-known member
This is the way that I would do it as well, except I usually start with a 1/8" drill then step up from there.
D KRAGER
Well-known member
Interesting, I never have tried a hole saw on thicker metal, figured it would just eat the saw alive. Anything over 1/2" that is covered up, I grab the torch.
Anyone ever seen a magnetic drill press? My dad has one. It's made for drilling semi truck frame rails. Electric magnet holds the drill to the frame, then it works just like a drill press, pretty neat. Would work good in Sberry's situation. Dad uses on all kinds of farm equipment.
Anyone ever seen a magnetic drill press? My dad has one. It's made for drilling semi truck frame rails. Electric magnet holds the drill to the frame, then it works just like a drill press, pretty neat. Would work good in Sberry's situation. Dad uses on all kinds of farm equipment.
Standard Lenox holesaws are made in East Longmeadow, MA. The steel can could be from a couple places, but it's typically going to be either of American or European origin (which would still require the "global components" label). They do the wire drawing, wire welding, toothing, welding assembly, and finishing steps here in the good ole' USA.
The "global components" description can refer to anything in the package you are buying, including the package itself. For a holesaw sold with an arbor, the screws and washers are likely foreign born. For a hole saw kit with a plastic case, the cases are made in low cost countries. For a carbide tipped holesaw, the raw carbides are probably of European origin.
If anything, newer Lenox holesaws last longer and cut better than "older" ones. There have been some not-insignificant upgrades to the tooth designs, materials selection, and heat treating over the years.
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A mag drill with an annular cutter would be perfect for this.
e-tek
Well-known member
I'd bet the metal comes from Canada!
This is a pretty wild thread. The title is "large holes though thick plate" but we're only talking about a 3/4" hole though a 1/2" plate. I almost said something when folks were suggesting a hole saw. Now we're up to a mag drill with an annular cutter! Only on the internet.
Just run some S&Ds through it step wise, be done with it, and enjoy your new bender.
Just run some S&Ds through it step wise, be done with it, and enjoy your new bender.
nissan_crawler
Well-known member
I can do a much rounder hole with a 3/4" holesaw, than running a 3/4" bit through.
I heard of a fantastic tip for using a hole saw on this metal--drill a couple of small 1/4-inch holes just inside the cut line of the hole saw--it gives the chips a place to fall through. It greatly increases the speed at which you progress through the material, and it keeps the hole saw sharper. I've used this method, and it's nice.
Another tip I've seen for a drill in thick material is to take a large fender washer, lay it over your mark, flat on the table, fill the center of the washer up with cutting oil, and then start drilling. The fender washer acts as a cup to hold the cutting oil. Done this too... worked decent.
-Brad
Another tip I've seen for a drill in thick material is to take a large fender washer, lay it over your mark, flat on the table, fill the center of the washer up with cutting oil, and then start drilling. The fender washer acts as a cup to hold the cutting oil. Done this too... worked decent.
-Brad
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nissan_crawler
Well-known member
good point on the holes for chips, if possible, this is the best way to go. If it's not possible, keep raising the hole saw up to get the chips out, otherwise the chips fill the teeth, then it won't cut and you just heat it up. I keep a large acid brush on the drill press for this. Raise the saw, run the brush across the teeth to clean them up, and drill again. Also, as stated, keep the damn things lubed. Oil is cheap. I just use Enco #1 fluid, IIRC, but I've used old motor oil, gear lube, whatever. Also, turn it SLOWWWWW. I run mine at 150 rpm's. Keep that thing cool. Once you overheat the holesaw, it's scrapmetal. done right, a single holesaw can do hundreds of holes in steel. Done wrong, you won't finish the first one.
I know the old U.S. made ones are good, but I don't know if the newer "global components" ones are are as good as, or not.
p.s. that "global components" could be china.
RobSmith
Banned
I used a 2" holesaw to cut through a 1" plate. I drilled 3 3/8" holes just inside the holesaw cut to let the chips escape. Low speed and some lubrication. Took about 15 mins.
I'm a former employee. I have a pretty good idea what goes into these products and where it comes from. There is maybe one non-critical component on them that comes from an Asian supplier.
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OccupantRJ
Well-known member
Have you ever stopped to think how large a 3/4" hole in steel plate is to a possible beginner, with minimal equipment, and consider trying to keep that person from getting hurt? We could have said to just stick it in his Bridgeport in back gear and have at it, but maybe he doesn't HAVE a Bridgeport. Maybe he doesn't even know what an S&D drill bit is. I learned through the years the hard way, that doesn't mean that HE has to.
"All you got to do is"
"Hey Y'all, watch this"
http://www.thefind.com/hardware/info-s+d-drills
sberry
Banned
I agree that this thread is about the easiest safest way with minimal equipment, holesaws are a great option. Can be done safely with hand drill.
Personally I think the cool part about this website is you have a lot of people with lots of different experience so they can all give their opinion and then you can make the decision of which way to go. Is a 1/2" piece of plate very thick, not to me but to my weekend warrior friends who are running an 18" ryobi drill press I am sure it is quite daunting. There are 100s of different ways to do any task and the more of those ways you know the better all around you will become.
Jared
Well-known member
The main thing no matter what you use to cut it is to run it a the right speed.
I see your point and respect it but suggesting a twist drill is no less appropriate to a "possible begginer" than suggesting an annular cutter in a mag drill.
They're made right here in East Longmeadow, Massachusetts. I know a couple people who work at the plant. Every hardware store in the area has a huge supply of their blades, and they're very good.
In addition to drill bits, you could also use a reamer, which IMO works better. You don't have to stay at a dead crawl speed with them either. they work at higher RPM's also.
Well, I vote for the hole saw. I've used them for various projects both with an 18v Dewalt drill and my 20" drill press. The only problem I had was when I ran out of regular oil and used some synthetic oil I had- BIG mistake! I was drilling 3/4" holes through 1/2" thick angle iron and went from 45 secs. per hole to over 5 minutes. The saw just sat and spun and would not cut at all. Well, lesson learned, and now I use synthetic oil in any lube application on my cars and tractors.
wineslob
Well-known member
If you are cutting through mild steel here is the formula:
CS(cutting speed) X 4 divided by the DIA (bit).
So it would be 100 X 4 (100 being the cutting speed of mild steel) divided by .750 = 533 RPM. The pilot hole should be just a bit larger than the web (or point) of the 3/4" bit. 3/16" should be just fine.
CS(cutting speed) X 4 divided by the DIA (bit).
So it would be 100 X 4 (100 being the cutting speed of mild steel) divided by .750 = 533 RPM. The pilot hole should be just a bit larger than the web (or point) of the 3/4" bit. 3/16" should be just fine.
dwilliams35
Well-known member
My vote's for an annular cutter: use one of those once and you'll never buy another hole saw...
That being said, a guy showed me a trick one time with a standard hole saw that really makes them work better: get a 2" or so thick sponge, then drill a hole through it with the hole saw. Leave the "plug" in the saw, soak it down with tap magic, and drill your hole through the metal: it was really amazing just how much it improved the cut...
That being said, a guy showed me a trick one time with a standard hole saw that really makes them work better: get a 2" or so thick sponge, then drill a hole through it with the hole saw. Leave the "plug" in the saw, soak it down with tap magic, and drill your hole through the metal: it was really amazing just how much it improved the cut...
sberry
Banned
I look at the time vs specialized equipment. I don't have any real machine tools, it wouldn't hurt but just don't want the additional tooling, my neighbor has it for the rare occasion where there is only one option where I cant work my way around most problems with simple equipment + a welder or torch. I maker up for it with battery drills, die grinders, etc with some specialized adapters, good selection of bits.
Even with specialized equipment I would likely be done with shortcut method before a guy has it rigged up. I hand drill almost everything, so fast, flip parts around in vise or clamp to table. Doesn't make advantage to do anything sophisticated when I am so proficient with hand drill. I like battery drill, worth every penny and then some, make things so much safer than hi torque corded units. We make a big deal about technology but use of hand drilling still makes up a good portion of the worlds work. Its a skill that should be invested in by most mechanics similar to welding.
As was stated in earlier post, some would find drilling a couple holes daunting task but with little practice can be done rather efficiently.
Even with specialized equipment I would likely be done with shortcut method before a guy has it rigged up. I hand drill almost everything, so fast, flip parts around in vise or clamp to table. Doesn't make advantage to do anything sophisticated when I am so proficient with hand drill. I like battery drill, worth every penny and then some, make things so much safer than hi torque corded units. We make a big deal about technology but use of hand drilling still makes up a good portion of the worlds work. Its a skill that should be invested in by most mechanics similar to welding.
As was stated in earlier post, some would find drilling a couple holes daunting task but with little practice can be done rather efficiently.