[buggyman]

I need to pierce some 5/8” holes through 1 inch thick hardened plate. I would normally drill a small hoe and use Oxy/Ace torch for this task. This plate is harder than my drill bits, so no pilot hole! I tried to blow a hole with a large tip on the Oxy/Ace torch, I got through one but, the second hole melted the tip. The plate which I need the holes cut through is sandwiched between a 1” plate on each side that is already predrilled, I have 13 holes to pierce.

I’m looking for recommendations on how to do these holes? Any help would be GREAT! Thanks, Paul

[Squirmypug]

Harder drill bits? Deeper cutting torch head? Air arc? Just some ideas, I haven't needed to drill anything this thick yet so I don't know what works.

[kermdawg]

I'd use a drill press and alot of oil if it were me. Will probably be pretty slow goin. what size tip are you usin on your torch? Might even need to adjust the flame a little bit as well.

[buggyman]

Thanks guys for the thoughts.
Drill press is not an option. This is a cutting assembly for a grader, about 1,200 lbs if I would take the time to take it off. The steel is harder than my best drill bits, so drilling is not an option. I have a plasma but it will not come close in cutting through an inch of hard steel. Also the hole is recessed an inch on each side, not making this task any easer....
My next thought comes from 40 years ago seeing some farmers using an Arc Welder with some kind of rod “they’d called a cutting rod” to cut metal. Maybe there is such an animal???
Any other ideas????

[delraydella]

Sears used to sell cutting rods and they worked great, but I haven't seen them in years. Have you considered a magnetic drill press? They work great on structural steel like I beams and are used a lot to drill rigging points in arena grids for concert lighting trusses. Here's one source for them...

http://www.csunitec.com/portable-magnet ... QAod_BXH4Q

They are expensive, but you may be able to rent one.

[weldin mike 27]

Hey,

Sounds like you have your work cut out for you. I have heard of cobalt drill bits, they are harder than normal but to what extent I am not sure. Another option is sharpening a masonry drill bit to look like one for steel. Also the Mag base drills are great. Heavy as hell but great. As for the cutting rod, WIA in Australia ( I am sure you could get something similar in any country) used to or still do sell a rod called a C and G rod. For cutting and gouging. A High arc force that blows away the metal similar to Air Arc Gouging but with just an electrode and no air. I suspect they would be messy as hell, but once you burned through you could clean it out with the carbide burr.

I hope this helps

Best of Luck
Mick

[jpence38]

What exactly are you doing to this grader? Are you replacing the cutting edge on it?

[finewoods]

Hi,

I'm coming at this with ignorance and naivete, so if my suggestion seems silly I apologize. Anyway, after reading the problem and some of the responses, I thought "Maybe diamond?!--a diamond or carbide hole saw--is there such an animal?" So I did a quick search, and lo and behold there seems to be an abundance of such creatures. Most are the chinsy, artsy types that are for the occasional hole in thin glass or ceramics, but I saw some more impressive ones by Bosch and Lenox. I didn't search long to find this--I'm sure there are others available of the heavy-duty, industrial variety. I'm not even sure about carbide--didn't look for them at all. Even the heavier-duty ones are described as being for glass, tile, etc. so some research and talking with manufacturers about the specific task at hand would be the next step. My gut feeling is that Lenox would be a great place to start--I'll bet their tech guys would love to help. If they don't have a ready solution, they'd probably love the challenge and give it some thought. If you end up using something to drill the holes you might want to consider flooding the drilling operation with a stream of water or grinding fluid to cool,lubricate, and wash away the particles of steel. Just some ideas....good luck.

[finewoods]

To add another thought. Sometimes it serves to look at things from a different perspective. Instead of trying to see it as a welder/ironworker, try to view the problem as a machinist. If you know any good machinists, ask them about possible approaches and available tooling.

[weldin mike 27]

Hi

How are you going with this project. Keep us posted.

Mick

[buggyman]

What exactly are you doing to this grader? Are you replacing the cutting edge on it?

Well I am adding scarifying blades onto the front of the current mounted flat blades. Currently there is a bolt holding the cutting blade on every 12 inches. The blade and the back of the moldboard have places for a bolt every 6 inches.
Someone added a 1 inch thick complete sheet of harden skin onto the moldboard at onetime and only put holes every other spacing.
I’m wanted to hold the scarifying blades on with spaces/bolts which were not drilled when the skin was added.

I do have cobalt drill bits, they just barely scratch/cut the skin; this would be NO FUN to drill 13 holes through one inch!

I have not worked on the grader for a while. If I can get something to put even a small hole, I can wash out hole to the right size with the Oxy/Ace torch.

Thanks guys for the thoughts : )

[finewoods]

I have no idea if it's feasible...you said it's too hard to drill...is it possible to first anneal just the spots where you want to drill the small holes with a torch to soften the steel and then drill the holes? If so, then you'd be able to finish them off with the cutting torch.

[ogorir]

if it were me, I'd give a shot heating it up red and trying to run a drill through it while it's hot. if that didn't work, I'd probably just eat the cost of the torch tips, because I don't see much of a way around it.

[SEAN]

YOU ASKED !! I
would be pretty sure if it is as hard as you think it is to me it sounds like BISALOY A Good way of knowing if the material is too hard to drill is it will flatten the point of your centre punch check this on any parts you've heated and see if the punch sinks into the steel if thats the case heat will help if not (I wouldn't heat it first i'm pretty sure it will harden like stainless if you've drilled a hole in stainless you will know if the drill is blunt and the material gets hot the drill will make a Squeaking sound STOP STOP STOP IMMEDIATELY) speed is turned down to slow first up the biggest problem that most people have with drilling holes is the cutting edges from factory finish is way too steep you need to flatten the drill out to about 50 deg even less (and this applies for every drill in your life and your enemies) i would be prone to use pilot hole with 3/16 find some cutting compound of some sort if you cant find any thing buy a plastic bottle of Coca-Cola (don't laugh) punch a fine hole in the end so you can squirt it if your still laughing buy ROCOL CUTTING FLUID if you have an extra set of hands get them to squirt the fluid in as you drill this will enable you to stay constant and not have to stop
Rule no 1 keep the cutting edges cool if the chips come out blue STOP cool the tip you don't want sizzling sounds when you cool the drill light steam is ok.
If you can stand above your drill clamp it between your legs (Don't do this if you have an old thumper that can turn the world) you can normally handle around 900wats if your not stupid about it and heres the bombshell PULSE the drill trigger ZIP ZIP ZIP add weight just after you pull the trigger and lift your weight slightly before you release the trigger!!! YOU DONT WANT THE DRILL TO COME TO A FULL STOP KEEP IT ROTATING TO SOME EXTENT THE DRILL ONLY STOPS WHEN YOUR PULLING THE DRILL UP AND OUT IF THE DRILL STOPS WHILE FORCE AND THE CUTTING MOTION IS STILL INITIATED IT WILL LEAVE 2 BASTARD BURS IN THERE !!!!! WHILE USEING 3/16 THIS WONT RIP YOUR ARMS OF WHEN YOU RESTART IT WILL MOST LIKELY BREAK YOUR DRILL OF IN THE BLIND HOLE BE CAREFUL BE CAREFUL
before you start drilling (PULSING) add the compound in the center punch and coat the drill now start zip zip zip add a nice amount of force Once the cutting edges are buried in the plate you should now see two strands now start varying your weight(CHIPS ARE NICER) if you only have one stop and re-sharpen the drill properly hold the cutting edges in front of your eyes they should be even in length and when straight or vertical the cutting edges should be higher than the trailing edge (Check this against the factory sharpened one) (the less relief the stronger the cutting edges will be But not enough and it will be slow going the relief sets how much material will come out per revolution)
IF this goes ok and your starting now to feel proud of yourself the you would be better to pilot with 8mm 5/16 instead of 5mm 3/16 then 16mm 5/8 drill hahaha same process (I KNOW IT SEEMS LIKE A BIG STEP UP BUT IF YOU GO TO BIG THE DRILL WILL PLAY UP ALL THE WAY DOWN THE HOLE THIS WAY YOU CAN ADD A BIT MORE WIEGHT AND NOT HAVE YOUR ARMS RIPPED OFF WHEN IT GRABS END UP WITH A BROKEN KNEE AND LAND ON YOUR APPRENTICE DRILL COOLER
1- flatten the cutting edges out MORE THAN THE 5-8 MM 2-keep relief to bare minimum enough to get the chip out TAKE IT REAL EASY TILL THE CUTTING EDGES HAVE DISAPPEARED AND LAUGH ALL THE WAY TO THE BOTTOM
IF YOU HAVE ACCESS TO COMPRESSED AIR USE THE AIR TO COOL THE DRILL AND CLEAN THE HOLE OUT AS YOU GO RUN THE AIR CONSTANTLY WHILE ADDING CUTTING FLUID
SAFETY RULES TO BE APPLIED 1- WEAR GLASSES 2- USE A DRILL YOU CAN SLOW DOWN AND PUT THE HANDLE BACK ON -3 -KEEP APPRENTICES HEAD WELL CLEAR OF HANDLE 4- IF YOU CAN CLAMP AN F CLAMP ON THE EDGE SO THE HORIZONTAL HANDLE CAN SLIDE DOWN IT YOU SHOULD BE ABLE TO HANDLE 16MM NO PROBLEM BUT BETTER SAFE THA 911
PS APPLY THIS TO EVERY HOLE YOU DRILL THE REST OF YOU LIFE SPECIALLY PEDESTAL DRILLS (IF IT HAS AUTO FEED AND CONSTANT COOLANT DIFFERENT RULES APPLY)V
IF THIS STILL SOUNDS DAUNTING BUT YOU CAN DRILL THE PLATE HIRE A ROTO-BROACH WITH MAGNETIC BASE DRILL THE SAME WAY AS DESCRIBED
SORRY IT WAS LONG I COULDN'T TELL YOU IN ONE SENTENCE

[buggyman]

Thanks Sean for the reply
I need to work on the grader again, it is almost Fall grading time.
Paul

[SEAN]

let me know when youve hit it with the center punch mate
these tips are for everyday life mate mild steel aluminium stainless even spring steel yep the stuff that holds the ass end of a ute up if you think you will have trouble sharpening the right angle set an originally factory sharpened drill bit use somethink large sit it on your grinder with the sharpened edge on the stone (not running of coarse) halve that angle and scribe a line on the grinders rest (the thing that supports the job best if the wheels nice and straight too) keep the rest well below the centre of the grinding wheel so when you put your finger on the rest to support the drill the cutting edge at horizontal is just above the centre on the wheel this will give you about the right relief angle slide the flutes on the drill on your finger with a litle flick of the wrist to the right
sorry if you already know how to sharpen a drill my bad
oh and use BORDO or SUTTON drill i find the last the longest

[TheExpert]

I am agree with kermdawg.

[mcostello]

Do you have access to a large arc welder? 6010 cranked up would do it.