Question on drilling hardened steel?????

[architect-builder]

Hey guys, I need to add 2 more KC lights to the front and was wondering if anyone knows what kind of drill bits you need to drill hardened or tempered steel???? I want to mount them to the sides of my transformer mount uprights, (they will be horizontal instead of vertical so to speek). I destroyed several of my bits and only got a 1/8" hole and I need 1/2". Is there a bit for this purpose????

Thanks,

Barrett

 

[BamaSixGun]

how about a carbide tip bit, and it may be good idea to use some oil to lubricate the bit while drillingv

 

[DaveBen]

Try the gold colored COBALT drills. They cut through almost all steels.

Dave

 

[RSG]

Sharp bits is must, I'm surprised at how awful many "cheap" bits there are to choose from. An aggressive steeper angle works best if you don't bear down real hard. The cheap cobalts I've bought haven't worked as good for me as carbide...and penetrating oil or other lube is good to pull the heat away.

 

[4drdually]

Solid carbide drill is a must, good oil (tapping oil, not wd40), and low speed with steady pressure. Nothing else will work good. My dad has been a tool and die maker his whole life and we own a job shop, so what i say is the truth. Question though, since when has warn made their bumbers out of hardend steel?? I seriously doubt its anything other than mild steel because putting that big of unit in an oven is ridiculously exspensive (more than the bumper) If you are drilling through stainless, i could see why it would be tough.

 

[jopes]

I have never had any problems drilling hardened steel like frames with my el cheapo harbor freight drill bits, but then again they never lasted long the first couple drills, but once I resharpened them with the drill doctor they drill like a hot knife slicing butter and lasted alot longer than the initial sharpening from HF.

 

[powerboatr]

Solid carbide drill is a must, good oil (tapping oil, not wd40), and low speed with steady pressure. Nothing else will work good. My dad has been a tool and die maker his whole life and we own a job shop, so what i say is the truth. Question though, since when has warn made their bumbers out of hardend steel?? I seriously doubt its anything other than mild steel because putting that big of unit in an oven is ridiculously exspensive (more than the bumper) If you are drilling through stainless, i could see why it would be tough.

and to add
GO slow make small curly chips vice tons of small dust
good cutting oil, start small work your way up to 1/2

 

[whatabudro]

one word, PLASMA

 

[bushpilot]

Hey guys, I need to add 2 more KC lights to the front and was wondering if anyone knows what kind of drill bits you need to drill hardened or tempered steel????

the simple answer is A SHAPE ONE....
sounds to me like you must have dulled the bit you were using.
go buy a "DRILL DOCTOR"...youll be shaperning bits all the time
(to make the job easier) as soon as you have one.

you can find drill doctors at your local hardare store in the tool
section (lowes/homo depot/walmart etc)

 

[Lord Tauk]

I'm a Machinist, I might be able to provide some insight into what you are doing.

First, how deep do you need to go? I assume you are doing this with a hand/pistol drill? Decent cutting fluid is probably a good idea, WD-40 can work - I've used it before when I didnt have anything else at home, but for something of that hardness, something better wouldn't hurt. Make sure you keep the drill cool.

Solid carbide is a no-no in my book as far as doing it that way, if you break the drill in the hole - especially a deep hole, you probably wont be able get it out unless you are lucky. Solid Carbide will also fracture faster than a cobalt or high speed steel drill.

I'd suggest a cobalt drill or a high speed steel (most common) with some cobalt in it, coated or not - since you're only going to drill a few holes no need to get real expensive and technical with it, but don't buy a cheap drill you can find anywhere. Also, as stated, start small on the size and work your way to the finishing size. I'd also recommend in buying a center drill or a spot drill versus using a center punch.

With the hardened steel and especially cast iron, it's almost better to spoon it out versus having something really sharp as depending on how good at finesse you are, you can fracture the drill point or render it dull within a few seconds of cutting.

Since you have a hole already there, you can buy yourself a finishing endmill, centercut or non-centercut - doesnt matter unless you dont have a hole there. Drill out the remaining using a 1/2 endmill. 4 flute would probably work best for the endmill route in what you're doing, again.. lots of options with endmills; carbide, HSS with tons of different coatings, etc. etc.

Again, this is all done by hand so anything will really work, you can go whatever route but if you go the cheap drill route make sure you get yourself some extra drills.

Here's a website to check out that has everything you need;
http://www1.mscdirect.com/cgi/nnsrhm