garrett1478

well i see theres a drilling metal thread a few threads down, but this is a bit different.

to put it shortly, what the HECK kind of drill bits are you guys using to drill steel?

me and chris need to make shackles for his truck. out of 3/8" plate... the holes need to be 9/16".

so we got a $20 bit from a hardware store, advertised to drill metal, 'good for drilling stainless steel'

yeah right. we got 1 hole done and its like the bit turned off. it wouldn't do a thing. we used cutting oil, stepped up in size a few times...

what's the secret brand to use?

marko3xl3

What's it made out of? I hear that Cobalt bits do a real good job.

photoleif

i always, ALWAYS use titanium nitride bits. they do a bang-up awesome job on wood and metal. they go through aluminum like it's not there. they eat up hardwood readily if you clear 'em often, and going through steel is far far easier than with a traditional high-carbon bit. i got a decent-enough set at harbor freight for $20ish -- 1/16 to 1/2 by sixteenths. kicks butt.

getitdone

The bit we used was cobalt. It was really sweet for that first hole. Metal chunks were flyin. We seriously stopped ever 10-20 seconds and re oiled the hole with cutting oil. The rpms where pretty low too. When it stopped working, it was all of a sudden. Like in between oilings, it just wouldn't do anything but ring.

This can't be the only way. I will lay down the green for a professional solution. I have to get these holes cut.

What I have used so far:
the generic steel ones - they suck.
titanium - doesn't last and really wasn't that effective
cobalt - the bit from heaven for just one hole!

I am wondering about carbide but I can't keep buying these 20 dollar bits!!!!

Please help.

kyle_22r

i like the black oxide bits, because you can re-sharpen them easily. titanium works good, too.

my secret: go real slow, and keep it oiled, and put pressure on it. high speed does nothing but round the bit off.

getitdone

How do you resharpen yours?

waskillywabbit

iTrader: (-1)

Drill press.
Generous cutting oil, NEVER let it get dry...contstant flow.
High speed steel bits. Hardware store drill bits are WAY WAY WAY overpriced and usually a POS. Find a local contractor supply store, bolt specialty shop, somewhere that sells high quality bits. I can get a high speed steel 1" bit for under $15.
Drilling a 9/16 hole is too big...start small and work up to the 9/16. Depending on your setup, I would have gone 3/16, 3/8, 9/16 or something like that.

I've got one 3/16" drill bit (titanium tip) that has drilled hundreds of holes, still as sharp as it ever was.

I frequently drill 3/16" thick plate (slider adapters and the like) and I've drilled thousands of holes over the course of the past couple of years...same DeWalt drill bits up to 1/2" by 1/64" (for metal) and a few larger high speed steel bits for select sizes.

Sounds like you just burned up the bit.

getitdone

Holy moly! I have the opposite success rate that you do.


So this is the recipe:

drill press,
high speed steel, titanuim tiped(purchased from contactor or equivalent)
about 3 steps to get to 9/16,
constant flow of oil

Am I missing anything?


Sounds too good to be true. I will throw it all down tomorrow after work.

waskillywabbit

iTrader: (-1)

Constant lubrication just means don't let it get dry...doesn't mean drown it...a little cutting oil goes a LONG way. Make sure you drill press speed (if it has an adjustable speed) is also set for drilling metal...as the setting will be a LOT slower than wood. On mine you move the belts on the pulleys.

You don't even need titanium tipped necessarily, just high speed steel. I have the smaller bits in titanium tips, the ones that I use repeatedly...like 3/16, 1/4 and 5/16.

A little more work saves you a lot of work in the long run...and money on drill bits.

snap-on

Its unlikely that you hosed a cobalt bit.

It probibly got hot and got a chip "welded" to the cutting edge.

I sharpen mine on my drill doctor and split point anything above 1/4"

getitdone

Well, I found a sweet shop. They weren't open untill today. I got some killer bits at a fraction of the cost. Thanks Brian!

When I got home and fired em up, I was somewhat dissapointed. They did nearly nothing. After another trip to the shop, we decided that the "scrap" that I got wasn't mild steel. It is something else, like maybe cast iron or something. Anyway, the only results I could get was with a solid carbide bit that was like 2 inches long. He only had just smaller than 9/16 so I have to ream the holes out to finish. I am drilling holes in 3/8 plate and 1/4 plate. Another thing that backs up the not mild steel theory is that the 1/4 cut like butter when done properly(described above) I was so amazed.

So tonights lesson, make sure you know what your getting from the scrap pile before you drill it.

waskillywabbit

iTrader: (-1)

Sounds like a "commercial" for teen abstinence to me.

SlightlyModified

I have continous lubrication. Set my press for the slowest speed. Last week, building ladder racks. I drilled 24 1/2" holes in 1/4" steel plate with one cheepo bit, without re-sharpening. I am having really good luck with a set of tin coated bits made by Clarke. Bout them at tractor supply. Alaways use several sizes to Step up.

snap-on

Have i mentioned comming accross the pice of Titaium sheetmetal back in school at the ME shop?

the local metal supplyer used to donate cut-offs and left over sheet crap like that for us to use on projects.

So some kid goes in the back finds a piece of 18" sq sheet that he thinks is AL cause its light and not rusty.

proceeds to burn up four 1/4" bits and hardly divit the surface. The shop machinest comes over and bout has a ˟˟˟˟˟ fit. "WHAT THE HELL ARE YOU DOING!?!!" were like.. makeing a bracket.... "OUT OF TITAIUM!" he says... were like.. oh that would be why it wont cut we tossed it back in the pile and dug out some AL.

waskillywabbit

iTrader: (-1)

Titanium is just a TAD pricey these days.

Epic Ed

I'm still trying to drill holes through the A-arm support truss from Schaefer. It is manly work! I punched the first thre 3/8" holes through the beam, the front side of the frame, the back side of the frame, and the other side of the beam. Probably an inch of steel total, and it was serious work even with titanium drill bits. I don't have much experience with kind of things, and then someone suggested I drill a 1/4" pilot hole. I tried that this weekend and still haven't made much progress on the last hole. I wasn't aware that slower is better and considered cutting oil, but there's no way for me to really get a good shot at the drilling location.

I hate to blather on without any solutions, but at least know that you're not the only knuckle-dragger out there unsuccessfully trying to drill through steel.



Ed

Cebby

knuckle dragger.......

86SR522REEFI

I just use a titanium step drill bit whenever I have to drill metal. AND LOTS OF OIL