Why can't I drill a 1/4" hole?

J

jkf96a

Well-Known Member
I've been using brand new Norseman stub length bits, drilling through 1/8 and 3/16 1080. I used a new 3/16 bit and drilled 11 holes and still had a little more left on the bit. I used two new 1/4" bits and only got two holes each. Running at my press' slowest speed, 620 RPM. What am I missing? Why the heck can't I get the 1/4 holes to work?
 
have you tried drilling a pilot hole before drilling the 1/4" hole? are you using any sort of cutting fluid? these are things I was told to try when I was experiancing the same problems. worked for me, should work for you too...
 
I had the same problem , I used the smaller bits and they worked fine . I then went to drill a 1/4" hole with new carbide bit from the "store" It was dull as it could be ? I had 2 of them so I put a new one in and it worked fine . I presume it was a dull "new " bit ??? I drilled a pilot hole and it just set there and smoked ???
 
What size on the pilots? I have tried a 1/8 pilot in the past, still smoked the 1/4 bits pretty fast.
Have tried WD 40 before with no noticible difference, except the mess.
 
I had similar problems and then I found a set of "Turbomax" cobalt bits at my local hardware store. I was amazed at how well they work. Even on my 1/8" carbide bits I was only getting a dozen or so holes drilled before they would smoke out. With the Turbomax, I drilled over 130 holes with a 1/8" bit with no fluid and it kept going (the 130 holes was in less than 5 minutes). I just hope I can find a new supplier when I wear these out. I'd hate to have to call Keith and ask him to go pick up bits and mail to me.
 
I don't know what brand they are but the bits that Jantz sells are great. I have a Drill Dr. sharpener and I hardly ever have to use it. But when I do they are just as good as new. The only way I have to replace one is if I break it. If it wasn't such a hassle I'd try to keep up with how many holes I could drill with one before it needed sharpening.
 
Bits may be the culprit.

I just use a set of pilot DeWalt bits from Home Depot, or cheap steps from HF but I've been able to drill dozens of holes so far by dipping them in motor oil using the $50 HF press. Are your bits hardened for cutting steel?
 
Which type of Norseman bits? HSS, cobalt?
What type of point and degree cutting edge?
Has the steel been annealed fully?

You should be able to get dozens of holes.
Use cutting fluid to keep things cooler.
The RPM sounds OK but you should be able to go at least twice as fast.
Use more pressure. It sounds like the bit is overheating and losing it's temper by too little pressure and just spinning and heating up.
Watch your chip. You want a nice curly chip, a thin one. It should not be all purple. That means too hot.
Clear the hole often. Use lots of cutting fluid to cool the bit. The bigger the hole, the hotter things get and the more you have to clear the hole and lube.
 
They're just the HSS bits. Steel should be annealed, came from Kelly Cupples. Chips start out nice and curly, but quickly get small. Maybe more pressure and some fluid is the answer, I think your lost temper theory is right on.
 
when drilling steel that hardens I have noticed that I do best with the slowest RPM, using cutting oil and not stopping. Once I start a hole I continue till I'm done. If the drill is dull and running hot it is possible for the metal to instantly harden if you back off then restart drilling. The hardened steel in the partial hole will be difficult to finish. I have heard of guys doing a spot anneal with a torch so they can drill the holes.

ernie
 
I use cobalt bits from Do it Best Hardware. Been going to this local store for years and the guy told me that the Do it Best brand cobalt bits have a lifetime guarantee. I said "even if I snap it in two?"...he said "yep"....I haven't had to test the life time guarantee yet though, but he's never lied to me yet. I have drilled at least 100 holes with the 3/8 bit I have and it's still going strong....I drilled all of the holes for my NWG with it and more..I've also drilled annealed 5160, 52100 and O1 blade steels with the 1/4" and 3/16"...some with cutting fluid, some dry...I've had several of them for at least a year and have yet to get one dull enough to sharpen...
 
When teaching people how to use the drill press, 95 out of a 100 don't use enough pressure. The bit just sits and turns and cooks. In cast iron steels, you get a gray powder looking stuff. In mild steel like used in a No Weld Grinder, it's so mixed up it is normal to hit hard spots. Press a bit harder when that happens. You should be able to feel the bit cut through the metal while it is lifting a chip curl. If you feel the bit bouncing on the surface and occasionally throwing out a small chip, you aren't pushing hard enough. Some stainless steels throw only small flakes of chips but even then, the flow should should be steady.
 
"Steel should be annealed, came from Kelly Cupples"

Thats a BIG assumtion ! I'd speculate you've got something hot rolled which will be terrible on drill bits and saw blades.

If this is the case the steel will be softer than hardened steel but harder than annealed and will have groups of carbides unevenly distibuted which causes "hard spots". You may drill one hole easily then squeel the bit on a hole right beside it or drill half way through no problem and then squeel the bit.

It's important to know for sure what condition your steel is in for several reasons. Most importantly when it comes time for heat treating if your dealing with hot rolled thats got large grain structure and uneven carbide distribution you'll end up with a knife that performs dismally in comparison with one that was correctly prepared for hardening.

I'm curious what kind of steel your using ? Whatever it is though I'd give Kelly a call and ask him if it's annealed or hot rolled.

-Josh
 
I made the mistake for a while of dismissing the value of good cutting oil... Wasted more than a few bits that way, and now I have found the greatest 1/8" bit ever (for me)... I've drilled about 40 holes consecutively on 3 occasions with little time between, and when it broke, I couldn't toss it so I just chucked it up short and kept going. I really wish I knew what brand or steel or SOMEthing about it to find a whole set.

Btw.. Boss.. Would it be wrong to repost this in my signature?
The bigger the hole, the hotter things get and the more you have to clear the hole and lube.
Click to expand...
 
BRad704 said:
I made the mistake for a while of dismissing the value of good cutting oil... Wasted more than a few bits that way, and now I have found the greatest 1/8" bit ever (for me)... I've drilled about 40 holes consecutively on 3 occasions with little time between, and when it broke, I couldn't toss it so I just chucked it up short and kept going. I really wish I knew what brand or steel or SOMEthing about it to find a whole set.

Btw.. Boss.. Would it be wrong to repost this in my signature?
Click to expand...

Yes it would now that I read it that way.
 
When drilling, do you try to drill the hole in one operation, in other words constant pressure until the hole is complete? What works best for me on annealed 1/4" stock, drilling a 1/4" hole is- drill with pressure for 2-3 seconds so the bit doesn't over heat, withdraw the bit let it cool for a few seconds, add another drop of oil, like cutting oil if you can find it or "3 in 1" and repeat the process until the hole is complete.
 
I could be wrong, but I doubt that WD-40 is an adequate cutting lube for drilling. Not unless you use a lot of it.

WD-40 is more of a cleaner than a good lube in my opinion.
 
I only use WD40 for scotchbrite belts, and keeping rust off blades in between working sessions...

Sears and Lowes and Home Depot all sell small bottles of cutting oil beside the taps... That is what I am using and it works very well.
 
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