Drilling through steel problems.

R

R.C.Reichert

Joined
Jul 26, 2008
Messages
1,006
I don't know if anyone else has encountered this same problem, but I wanted to share an interesting thing I just discovered today....

I have these large blades of 5160 that I originally drilled 1/8" holes into the tang. The 1/8" bit drilled really easily through the 1/4" steel, no problems there. Later on I changed my mind and decided I wanted 1/4" holes in the tang for the pins instead of 1/8". This is where the problem started. It seemed that because there was already a smaller hole in the steel, when I went to drill into it with a larger bit, it did not want to bite into metal. The larger 1/4" bit just spun out in the 1/8" hole and made a bunch of noise and causing the bit to go dull in just a few turns. Tried going slow even, but that didn't seem to work either. Ruined two brand new drill bits trying to drill out one hole.:mad: I even tried using a Cobalt bit, but it wrecked that one as well.:mad: For whatever reason, I could not get the 1/4" bit to drill through. I had a similar problem before with some 1095 that I was trying to drill through. I don't really know what causes this problem, but I did find a rather unorthodox solution. I found that instead of an actual drill bit, I put a small carbide cutter in the drill press instead. I'm guessing it's the shape of it or something, but I got all 6 holes for both blades drilled out with this with no problem at all. It drilled the holes smoothly and quickly without even damaging the little cutter. And these little bits are made for wood carving! I used to use concrete bits when I was having problems drilling, but these small carving bits seem to work even better. I think it's because they cut more from the side I'm guessing?? Will try to post a picture of the small carbide bit's I am referring to. I used the "flame" shaped one. Worked like a charm! Perhaps there is a way to use just the regular bits to re-drill the holes, but I have not found that method yet.

10pcCarbideBurSet.jpg
 
Last edited:
My guess is that your steel is not annealed, and if it's 1095, it has plated out carbides that are going to laugh at a drill bit. The reason your carbide cutters cut is just that...they're carbide, and are MUCH harder than steel, so it's like drilling soft brass for them. You're going to break them if you're not careful. They don't like chatter or misalignment. That said, I bet they do cut like a beast, and in a drill press probably work excellently. I'll have to try it.
 
I know for a fact that the 1095 I tried before was not annealed properly, but the 5160 is annealed. I could take a 1/4" bit and use that alone and it'll drill a hole into the steel no problem, with ease, if that is the bit I start with. The problem seems to happen only when I try to re-drill out a smaller pre-existing hole, it just wrecks the bit. It seems kinda odd, I know.
 
It's because the heat generated by the 1/8" bit causes the steel around the hole to harden.
Stan
 
SBuzek said:
It's because the heat generated by the 1/8" bit causes the steel around the hole to harden.
Stan
Click to expand...

That is really interesting. I never thought about that.:cool: I thought the steel had to get red hot and then cool quickly in order to harden.
 
I agree with SBuzek . I was told the first time I used some large 5160 and was drilling a series of holes for a hawk head not to stop drilling in the middle while going through the block. The bottome of the hole would harden and when you tried to restart the hold would burn the bit up.
 
Thanks for the info on the use of cutters.

With the carbide tip masonary drill bits I do some times re tough them for a sharp edge. I also use a slower speed and may be a little more pressure to get them through.
 
I find with 5160, O1 and 1095 if I don't drill the hole through completely the first shot... it air hardens, wrecks the drill bit and squeals like a b!tc#.

... or something like that.

Rick
 
Magnussen said:
I find with 5160, O1 and 1095 if I don't drill the hole through completely the first shot... it air hardens, wrecks the drill bit and squeals like a b!tc#.

... or something like that.

Rick
Click to expand...

Yeah, that's exactly what it's doing. Man does it ever squeal!!:D
 
I have not had this problem for a long time. I regularly drill a small pilot hole and then go progressivly bigger to arrive at the size of hole that I want. I have burnt bits and screwd up things by using to fast of a speed (rpm) and no oil or tried to drill a hole with a dull bit and srewd it up that way.

What speeds are you using and are you using a cutting fluid? I use about 800 rpm for a 1/4 inch hole and 1200 or so for a 1/8th This is slower than reccomended but since I started doing this I haven't had any problems. keep in mind that the larger the bit you use the slower it needs to turn. with proper spped feed and lubrication you should be able to start stop and redrill with no problems.
 
Quote:
Originally Posted by Magnussen
I find with 5160, O1 and 1095 if I don't drill the hole through completely the first shot... it air hardens, wrecks the drill bit and squeals like a b!tc#.

... or something like that.

Rick
Click to expand...

Yeah, that's exactly what it's doing. Man does it ever squeal!!
Click to expand...

Once the sqealing starts the drilling doesn't go any deeper:(

I either do it like Rick - one shot through, or go slow stopping frequently to spray with WD-40. Cobalt bits rock:)
 
Jigalube (silicone spray) is great for drilling and tapping. Though, I haven't looked into the chemicals I'm breathing in with the smoke... cough-cough
 
Bill Burke said:
I have not had this problem for a long time. I regularly drill a small pilot hole and then go progressivly bigger to arrive at the size of hole that I want. I have burnt bits and screwd up things by using to fast of a speed (rpm) and no oil or tried to drill a hole with a dull bit and srewd it up that way.

What speeds are you using and are you using a cutting fluid? I use about 800 rpm for a 1/4 inch hole and 1200 or so for a 1/8th This is slower than reccomended but since I started doing this I haven't had any problems. keep in mind that the larger the bit you use the slower it needs to turn. with proper spped feed and lubrication you should be able to start stop and redrill with no problems.
Click to expand...

Same here. It seems like your wasting time drilling lots of holes at first but drill bits last many times longer and you rarely get problems with bits not drilling.

I use baby oil as lube and just go slow.

(And yes I was still talking about drilling steel.)

Jamie
 
It's a common practice to drill a smaller pilot hole, then open up with larger bit.
So that isn't the prob.

Could only be, steel too hard, poor quality drill bits, or too high RPM.

Your use of carbide bur is a good back up plan...
 
It sounds to me like you got it hot when drilling the 1/8 inch holes. I drill pilot holes all the time and then go larger so that should not be a problem. Is it possible your running the bits a little fast or with no oil? A friend of mine ruined a bit drilling some holes in ATS 34 a while back. He ran it too fast and even though he put oil on it he had it smoking and next thing you know he dulled the bit and by the time he got through burning the heck out of it he had hardened the blade. I had to anneal that blade to finish it. I could drill hundreds of holes with the same bit by using the right pressure and speed.
 
The speed I was using was 620 rpms. This happened to me using expensive cobalt bits as well, but they do last a little longer. The steel is not hard since I can use a cheapo bit and still drill though it with ease. I even tried using some oil to lubricate the bit. I am thinking it might be when the larger bit tries to compensate for the reduced angle of the previous hole (the outer rim of which may have hardened from the heat), perhaps I am using too much pressure, but it ruins the bit and squeals like mad. At least the carbide burrs work well to make the hole larger. I should just go get myself some carbide drill bits, but they are :eek:expensive. Thanks for all your suggestions.:)
 
You must be hardening the outside of the hole when drilling the smaller hole. I've never seen a drill bit that wont "bite" into steel better when following a pilot hole so if anything the 1/4 inch should try to drill into it easier following the 1/8 bit. Like I said, a friend of mine was helping me a while back and got a blade too hot and it did exactly like your describing.
 
620 RPM is a functional speed for a 1/4" bit. Your bit engagement should be firm and hesitation-free (i.e. don't be shy).

Try water-soluble oil as a coolant/lubricant. MSC sells Rustlick brand in 1-gal jugs. I squirt it out of a wash bottle, flooding the workpiece and tool.

304 will work-harden too... I'm not sure what the metallurgical explanation is, but it does work-harden.
 
Ive used carbide die grinder bits and diamond bits they are a larger version of the dremel tool ones. Princess auto carries them .
 
You must log in or register to reply here.
Back
Top