Unbelievable issues when attempting to drill holes...

[RKM556]

Hey all! 

 

So okay, I am trying to learn to make swords, since I can make knives pretty well at this point. So instead of forging my first sword like I normally do my knives, I decided to go ahead and try just a stock removal sword (yes I know it's cheating. I am not selling it or anything) and see how it went. Made a few jigs... ect. ect.

 

My problem happened this evening when I tried drilling a couple holes for the tang to secure it very well. I am doing a full tang just to experiment because like I said, I am not selling it. Okay so back to the problem, my drill bits decided that it would be impossible to drill through this material. I have never had issues with this, my drill bits are sharp Cobalt coated bits that were very expensive. My drill press is 3/4 hp. Shouldn't have too much of a problem drilling, it would seem. However, none of it worked. 

 

The steel is 5160 from Aldo. 

 

Maybe it was pre hardened or something?? I have no idea. I don't usually do stock removal. I was nervous to anneal just part of the blade (handle) because I have to send it off to Peter's Heat Treat because the blade is too big. But, I did it anyways... twice. I don't think it will help a second time, but it is cooking in ashes right now. Does anyone have a suggestion on how to drill my two holes? (that sounds absurd...)

 

Thank you for any and all of your help!

 

Your Friendly Neighborhood Blacksmith-in-the-making

 

Ryan

[Metalsmith21]

Did you try using a metal cutting/drilling lubercant? When was the last time the bits were sharpend? And yes it does take quite a while to drill through metal, much longer than it is for wood.

[RKM556]

Yes, and yes they are sharp. I spent an hour and 15 minutes on one hole.... Still not through...

[HWooldridge]

I just got finished drilling some annealed 5160 with plain, old high-speed twist bits and had no problems. I suspect your attempt was on a hardened section. If the bit just squealed and got dull, the stock was too hard.

[RKM556]

That's exactly what it was doing. How strange. I guess I will need to resharpen my bits then?

[arftist]

That's exactly what it was doing. How strange. I guess I will need to resharpen my bits then?

In your case I would buy a solid carbide spade bit. I have never had a problem drilling 5160 up to about 5/16". After that it gets tough. You could spot anneal if you had to, but the carbide bit will end your worries. 

[arftist]

That's exactly what it was doing. How strange. I guess I will need to resharpen my bits then?

Once you sharpen "cobalt" bits they are just high speed steel. 

 

 

 

not true, please site  where you heard this?

[JNewman]

I am shocked at how bad even a lot of expensive big box store drill bits are.    Buy your drill bits at an industrial supply house better bits are often cheaper.  In smaller sizes I usually buy at least a couple of a size I need.

[Anachronist58]

Hmmm, Cobalt is not a coating, (do I stand to be corrected?) but Titanium Nitride is. A True High Speed "Cobalt" twist drill is cobalt-steel alloy, thru and thru.

 

Definitely sounds like work-hardening. Spot anneal? sounds like good advise.

 

What Diameter Hole?

How many RPM?

What kind of chips were you getting? 

Do you know what chips are?

Have you sharpened in the Past?

 

People usually arrive at your misfortune by Excessive RPM, Insufficient Feed Pressure, or Lack of [Oil], of a combination of two or more of those three.

 

Or the material was too danged hard to start with.

 

Nothing wrong with a a carbide spade, I suppose, but the unwashed can wreck those, too.

[HWooldridge]

That's exactly what it was doing. How strange. I guess I will need to resharpen my bits then?

If they squeal and don't cut, then they have gotten dull. As Arftist mentioned, carbide spades are good for hardened steel - use high feeds and speeds since carbide likes hot and heavy stock removal.

[BIGGUNDOCTOR]

You can do a spot annealing/tempering where you want the holes. Sharpening won't help if the material is too hard, you'll just dull the bits again. To spot anneal you can use a heated bar that you hold against the tang, use a torch with a heat barrier on the blade, use a mig welder as an electric heater, etc....the main thing is giving it enough heat for enough time. Thin sections of non air hardening steel will air harden, so keep it hot for some time for best results.

Yes, cobalt drills have cobalt throughout them, it isn't a coating.

Good luck, and let us know how it works out.

[the iron dwarf]

when a drill bit gets hot it will anneal and be soft and will not cut

if your drill bits are coated then they are not cobalt but nitrided ( or should be ) have seen some in the past that were just coloured to look nitrided but were real soft.

do you know how to sharpen drill bits? check chisel point, rake and cutting angle is correct

[RKM556]

Wow thank you all very much for you help. I will look into carbide bits. I am trying to drill 1/2 inch holes, which is super thick, but I have been able to do it before. I also tried using brand new drill bits that I have never used to drill through, and that didn't work. I will try spot annealing as you all said, then I will try using a carbide bit. If this doesn't pan out I will just drill a smaller hole. I have drilled through 5160 a whole bunch, but uually after forging the blade so I anneal the whole thing. I guess my problem is that it hardened when I worked on it, or it came a bit hardened. My RPM was about 460, as slow as my drill press can go. 

[Dogsoldat]

Did you try drilling a pilot hole first and stepping up from there or just start with the 1/2" bit.  Can be rather hard to push the chisel point of the bit through some materials but starting small and drilling progressively larger hole til you are at the size you want may work.  That and a good cutting oil can make a world of difference.  But it all may come down to spot annealing

[SimonW]

Maybe there was a layer of scale on the bar that dulled the bit before you even got into the steel? Also, maybe check that the drill press wasn't running in reverse (it rare but possible to do with some presses), that really doesn't work!

 

If your drilling such a big hole, do it in steps, it will save you a lot of time & be much cleaner. Try 1/4" to start, then up to 3/8" & finally 1/2". Always use cutting fluid (motor oil will do in a pinch), and as before, make sure your RPM isn't too fast. 

 

I'd suggest annealing the bar though, or at the very least the sections where you will be drilling. Once you are done drilling & all the edge beveling you will want to anneal & heat treat the blade anyways, so there's no reason why you shouldn't be able to anneal.

 

Good luck! 

[the iron dwarf]

when you buy drills they are often not sharpened to the right angles.  also the cost of drills does not always match the quality.

I had a job involving 500 holes in 1/2" stainless, holes were about 1/2", the guy I share my place with had gone through several expensive drills without doing a single hole but I did the 500 with 2 drill bits, he taken a couple of hours to not do 1, IIRC I took half a day to do 500

[arftist]

Wow thank you all very much for you help. I will look into carbide bits. I am trying to drill 1/2 inch holes, which is super thick, but I have been able to do it before. I also tried using brand new drill bits that I have never used to drill through, and that didn't work. I will try spot annealing as you all said, then I will try using a carbide bit. If this doesn't pan out I will just drill a smaller hole. I have drilled through 5160 a whole bunch, but uually after forging the blade so I anneal the whole thing. I guess my problem is that it hardened when I worked on it, or it came a bit hardened. My RPM was about 460, as slow as my drill press can go. 

Way too fast for such a big hole in hard steel. 

[Frosty]

Ryan: 100rpm max. 1/4" pilot hole then to 1/2". No drilling in really small increments is NOT a good thing, no less than 1/3rd increase i diameter or you'll chip out the outsides of the edges. With a little proper technique you can drill as quenched hardened 5160 with a cobalt bit.

 

Using carbide bits requires MORE skill than using standard bits. Having the tool does NOT mean you know how to use it.

 

About the cobalts you burned: toss em they're scrap you don't have the experience nor equipment to re-heat treat them.

 

Oh for the days they offered shop classes in Jr. and high school. You would've studied and passed all this info before getting to put a project in a drill vise. Not your fault Ryan, I just get ticked about modern education is all.

 

Ain't we all Charles, I just don't catch you in one very often. I'm just not that swift.

 

Another aspect of small pieces of solid fuel in the fire, the increased surface area allows the fuel to consume more oxygen so the fire's sweet spot will be closer to the air blast and hotter.

 

I've found it doesn't matter what kind of fuel I use, I can burn steel with em all.

 

Frosty The Lucky.

[arftist]

Ryan: 100rpm max. 1/4" pilot hole then to 1/2". No drilling in really small increments is NOT a good thing, no less than 1/3rd increase i diameter or you'll chip out the outsides of the edges. With a little proper technique you can drill as quenched hardened 5160 with a cobalt bit.

 

Using carbide bits requires MORE skill than using standard bits. Having the tool does NOT mean you know how to use it.

 

About the cobalts you burned: toss em they're scrap you don't have the experience nor equipment to re-heat treat them.

 

Oh for the days they offered shop classes in Jr. and high school. You would've studied and passed all this info before getting to put a project in a drill vise. Not your fault Ryan, I just get ticked about modern education is all.

 

Ain't we all Charles, I just don't catch you in one very often. I'm just not that swift.

 

Another aspect of small pieces of solid fuel in the fire, the increased surface area allows the fuel to consume more oxygen so the fire's sweet spot will be closer to the air blast and hotter.

 

I've found it doesn't matter what kind of fuel I use, I can burn steel with em all.

 

Frosty The Lucky.

Good points Frosty. So often I don't see the whole picture and just spout out the "facts" without taking into account the experience or lack there of. 

Especially good point about trying to take too small of a chip and putting all the strain on the edge of the bit. 

 

These so called cobalt bits, though, I am not seeing them around here at least. There are some gold colored bits that definitely cut a little better and last a little longer but once you sharpen them they are just HSS.  I assumed that's what people meant by cobalt, but I guess not. 

[Steve Sells]

When I went to the store to get more 1/8 inch bits I saw I had 4 choices for drilling metals, 

1)  the flat black HHS bits                                $2.35 ..2 bits,

2)  poilished golden Tinanium Nitride coated  $2.35  .. each,

3)  a satin oiled bronze colored cobolt            $8.30 each

4)  glossy black carbide tipped                       $15.39 each

 

each one has different purposses

[Rich Hale]

I drill hardened steel only rarely and for that I use carbide. Pricey and if youi do not use them right they break like glass...it takes a special wheel to sharpen them. My day to day drill bits I use i get from harbor freight on sale. I think they come in a pack of six,,,,cheap. I rarely sharpen one..it is not worth the time. I drill steels that have been annealed. That includes high carbon steels like 1084, 1095, L6, 15N20, and 0-1. Also a few high carbon stainless such as 154 CPM, 440C and ATS 34. The key to drilling is not only speed but feed as well. For instance: 154 CPM work hardens really fast. If I am drilling and let off on the downforce a little bit the bit is not drilling and heats the contact area enough to harden it...that bit will not get through the hard spot. I can finish the hole with a carbide bit..I use twist carbide and not spade.

One issue I have with the HF bits is they are not sized correctly..The 3/32" bits are always undersized..so i use drills from other big box stores when needed.

There are charts for the speed you need for every size bit. I have not seen charts for down force needed.

Anneal that piece and then step through the heat process.

[Anachronist58]

Numerous times I have read posts by numerous members about how many poorly made twist drills are for sale out there.

 

But if we were to take Rich Hale's statement in Post #21, Make a Poster out of it, and hang it by our Drill Presses (and read it!), All lot of us could avoid a lot of the headache and 'Mystery' of Drilling Good Holes.

 

[Down] Feed is not a function of pressure, but rather Distance Traveled, as in inches/mm per minute, or inches/mm per revolution.   And that information is found in a 'Speed and Feed' chart.  Feed pressure on a manual drill press is controlled by biofeedback, as the Operator learns to 'feel' the drill feeding into the material. 

 

You might find it hard to believe, but Experienced Operators know that it becomes easy to 'feel' even as little as .002" per revolution on a [good] manual machine. As Rich points out, "If I am drilling and let off on the downforce a little bit" that's called 'dwell', and at that point, the game is up.

[Anachronist58]

Numerous times I have read posts by numerous members about how many poorly made twist drills are for sale out there.

 

I would love to name two very famous manufacturers but they are still in business, and may by now have corrected their Quality Assurance Escapements, and thus, I will substitute trade names with pseudonyms (these are otherwise 100% 98% true stories):

 

The FreddyDrillCo has been selling the Bonbon 33 M7 (0% Cobalt) HSS drills with their 'Revolutionary Design' since the '50's or 60's. and I agree, these drills work as slick as Deer Poop (Thanks, Frosty).

 

Every one of these drills has the date of manufacture printed right on it.  While Reconditioning some of these dated from the 1970's I spotted a manufacturing error on almost every one of them.  The drills, when manufactured, would be ejected from the work-holding, and on their way out would fail to clear the grinding wheel. The wheel would nick the corner where the cutting edge meets the diameter. This portion of the geometry is critical to the performance of the drill.  I soon discovered that drills dated 2011 had exactly the same Escapement (defect).

 

I guess the drills perform well enough, but it makes me angry because of measurable loss of Value.

 

PeachyKeen, a leading industrial supplier, grinds certain lines of its drilling products on the fifth floor.  The machine kicks the drill out of the fixture, and the finished drill (less surface treatment) drops into a pile of its siblings in a bucket in the basement. Sometimes it doesn't pay to look at stuff through an Optivisor or a 15x microscope. I have seen from the same company with drills that are differentially hardened, the shanks are hard and the cutting edges are soft.  I think i have those somewhere in my museum......

 

I don't consider many drills from many vendors to be 'Ready to Use' right out of the package they are more like 'semi-finished' tools in several ways.  And Yet, we are able to drill lots of holes (most of the time) with even these.

 

All I am trying to put across with all of this is that some on this forum can get the job done with a 'broken beer bottle'. because of technique (see Post #16, Iron Dwarf).

 

I guess I've expelled enough wind, I'm halfway to Hawaii.  But one last Puff:

 

I have found a really nice Reference on line, Indeed, a chart, that breaks down the Chemical Composotion of the various High Speed Steels.  It shows 30 types of HSS. It seems to match 'sanctioned'  documents I have used in the past.  For example, M42 High Speed Cobalt:  C=1.10%; Cr=3.75%; V=1.15%; W=1.5%: Mo=9.50%; Co=8.0%, By Weight.

 

I would be happy to post the link to the site it is a really nice chart.  But I wanted to review IFI Forum Rules first, and after ten minutes - I give up- couldn't find 'em.  I guess I'm not as smart as I look......or is that, people smart when they look at me???

 

 

Rules links are in the lower right corner of every page, scroll all the way down, and YES you  can post a link for the charts

[Anachronist58]

Thank you Moderating Team.  I saw that 'Terms of Use' down there and said, "Naw, that can't be it!" Back to school, <sigh>.

 

Link to aforementioned chart:

 

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Link to Sponsor Site:

 

http://www.keytometals.com/page.aspx?ID=CheckArticle&site=kts&NM=236

 

Hope some find this beneficial........

 

Robert Taylor

[the iron dwarf]

having power feed helps a lot, stopping the feed is often the cause of problems on difficult materials