Drilling through 1/4" steel.

[badatwelding]

Long story endless: I ordered trailer plans from Master Plans and so far so good. (I'll post pics someday) I'm building the ramp and the plans call for making the hinges out of 1 3/4" X 3/16" plate, which was hard to find. But genius me I decided to improvise and upgrade and use 1 1/2" X 1/4" thick plate. I have to drill 1/2" holes for the 1/2" bolts. (diameter btw) So I'm drilling with my Dewalt 14 volt cordless and it's slow going. So I run to Lowe's and buy a smoking new Milwaukee Drill. (7 amps something like 3000 rpm, debit $135.00) Back at the house...still pretty slow. Go to Ace Hardware and purchase new Dewalt 1/2" cobalt drill bit. (debit approx $20.00) Back at the house...Success! For exactly 1 and 1/2 holes I'm a drilling machine! Then things slow down again. The bit got dull. Talked to a "do it yourselfer"/fireman/Civil Engineering friend and he said slow the rpms down and oil the bit every so often. Any suggestions, people??? I have 6 holes to go and don't get paid again for two weeks.

Thanks.

[rlarkin]

You want the drill speed to be as slow as possible. What happens is that as the bit dulls at high speed, and you continue to drill, you work harden the steel and toast the bit.

If the drill has a low speed screw setting, try that. You want 300 or less.

[Sberry]

That new Mil you bought has its place but I like the 1/2 850 rpm model. Way better, at Lowes they might let you trade up if you are not a happy camper. About 15$. Sharpen the bit, or replace it again and get a smaller one, 3/16 or so and drill a pilot hole. Step drilling and a new bit you probably could have done it with the 14.4.

[Sparkeee24]

Howdy Howdy! I had these same issues while I was building my Scout 4X4 setup. S L O W down. I went through 4 ti coated bits in about 20 holes. thats back when I was ... less experienced. if you can't hold your finger on the drill tip, then it's too hot. Your losing your temper out of your bit very quickly. Also, any handheld drill has the tendency to wobble the hole, or put pressure on one side of the bit at a time, and not put even pressure on it, wearing out the bit extremely fast. If you can rest something next to the drill, or use it in a manner so your body is maintaining the bits angle and position constantly. I use a spray on cutting oil. not just any oil... CUTTING oil. the spray stuff foams up, and moves slowly so it doesn't just get shoved aside with the first few chips. Can't stress enough about cutting slow. My drill press can do about 300 rpm - 2100 rpm and I have it on it's slowest setting for drilling steel. you gotta be patient is all. If you can't see the individual flutes, if they blur together when turned on, then it's going too fast. Use steady even pressure, do not force the tool, let the tool do the work. at the same time, don't use so little pressure so the bit doesn't cut at all. that will cuase gualling, and the steel your cutting will temper and harden. then it'll be REAL hard to drill. You can tell alot from the shavings. the BEST shavings are curlies. long continuous curly shavings. means great cutting efficientcy. You can't really get that with a hand drill. Well, get some oil, buy a couple bits, use em like you should, and then save em. Take em all in at the same time to get sharpened. Costs about 2$ each I think... or you can get your own sharpener. or find a friend with one. Good luck Brian Lee Sparkeee24

[alanh]

I think drilling holes in 1/4" steel should be a snap. Your drill probably runs 300 rpm, not 3000, and if you're having problems, try some cutting oil on the bit while drilling, and drilling a pilot hole for the 1/2" bit to follow will also help. For a 1/2"bit, about 1/8" pilot hole would do fine.
The next purchase, if you don't have one, must be a grinder, and then some practice on sharpening drill bits. You can use a bit for a long time if you keep it sharp and shaped properly. Never get the bit hot when grinding on it to sharpen. Proper sharpening is just like welding, the more you do it, the better you get.

Good Luck

[Zrexxer]

if you can't hold your finger on the drill tip, then it's too hot. Your losing your temper out of your bit very quickly.

Unfortunately, that statement just isn't true. Cobalt steel retains its hardness well into the red hot temperature range. You'd most likely burn up a portable drill motor before you ever lost the temper in a HSS or a Cobalt alloy bit.

However, what Brian said about shavings... chips, actually... is right on the mark. If you're not keeping feed pressure on and making chips, then you're just creating wear on the bit. That's probably the single biggest problem in drilling metals with a hand held drill motor, you have to keep the pressure on and keep making chips.

[Hotfoot]

Try this. It works. Get cutting fluid (Home Depot even has it). Use small starter (Pilot) hole, dosen't even need to go all the way through...keep plenty of cuttting fluid in hole....Now (the magic part)
My 3/8" 110volt Dewalt cuts better for some reason than my fully charged 18 volt, and my 1/2" Bosch cuts better than either of them....dunno why.

[Mike W]

I drill a 1/8" pilot hole on everything that I drill. With a hand drill, you might then go up two larger sizes before your final hole size. It is a lot easier in a drill press.

[unixadm]

Sounds like you should have spent $129 on the cheap Tradesman drill press they stock at Lowes. I have one right now and while it's not ultra smooth or ultra tough, it does the job drilling holes in steel. Also - I don't drill 1/2" right off the bat. I use a smaller cobalt bit to do a pilot hole and then I step up to the 1/2" bit. Take that drill back and buy the cheapie drill press. Use a good cutting oil and a slower drilling speed. If you do get a press, make sure you clamp the material very securely.

[Broccoli1]

Sounds like you should have spent $129 on the cheap Tradesman drill press they stock at Lowes. I have one right now and while it's not ultra smooth or ultra tough, it does the job drilling holes in steel. Also - I don't drill 1/2" right off the bat. I use a smaller cobalt bit to do a pilot hole and then I step up to the 1/2" bit. Take that drill back and buy the cheapie drill press. Use a good cutting oil and a slower drilling speed. If you do get a press, make sure you clamp the material very securely.

Ditto!!! I have a Craftsman. After you drill one hole you'll smack yerself for not getting one sooner

[Broccoli1]

I swear this little cheap set is great.
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[Sandy]

Just as a side note, I've never been real tickled using cobalts with hand drill motors. They chip up too easy. Plain ole HSS is as about all around hardy as you can get.

[Fishy Jim]

Those look like a red case version of the dewalt ones I get on sale for around $14. Burn em up and buy another. They get dull more than they break.

[Mike W]

Learn how to sharpen your drills. I bought some US made HSS in Korea while working for uncle Sam many years ago. I still have almost all of them. I have broken a few of the number series but only one in the larger set.

[Winger Ed.]

Any project like this is a perfect reason to buy more power tools.

You need a drill press. I got a basic home Depot one-- the 1/2" one I think with the pullys on top to change the speed.

Stuff that I used to grunt & groan over for about 30 minutes per hole, usually having the drill jam and spin around popping me in the face at least twice per hole,,,,, I do the same thing with the drill press & plenty of cutting oil, and it goes through the same size steel like it was wood.