Problems with Steel

[Roskrow]

I have never tried to post a new thread in HMEM so just hope this is read.

I have recently needed to drill small holes (5/16th) in Mild Steel. But I have found that although almost all drill with ease I have recently had a number of holes that just will not allow the drill to penetrate. I think I have totally ruined some 5 or 6 drill bits.

Is the problem poor quality steel or is it just me ?
Any assistance in giving me a solutioin would be greatfully received

 

[Cogsy]

Sounds like you're either trying to drill something that is too hard for the drill bits, or your drilling technique is work hardening whatever material you're trying to drill (some materials work harden a lot easier than others). The final option, and a mistake I have made once or twice, is managing to run the mill/drill backwards which never works.

 

[Roskrow]

Thanks, I hear what you say, but if you are grilling 2 foles adjacent to each other, with a long pause between each I just do not understand why hole A drills easily, and hole be will not. to the extent of totally ruining the drill bit.
I have a friend who has just had the same exoerience (he is a trained engineer). He needed to drill 3 holes in part of a garage door. holes 1 and 2 no problem. but hole 3 +was so hard that even a cobalt drill found it hard going.
His opinion is that the scrap yards that remit scrap to India are not careful in their sorting, which means when the scrapis re-melted it is muddled up with various grades

 

[Roskrow]

Cogsy, I have just noticed that you live in WA. I was there from 1962 to mid 1970, i was in Real Estate. Amongst many other propertie i for a perion owned Bay View Mansions in Claremont. Whre do you live and what do you do, or did do ?
Best wishes Malcolm Farrant (Roskrow)

 

[SmithDoor]

Sounds like bad drill bits.
They made drill bits for wood that just not last.
I have a package of drill bits from 1950's that will not drill steel.

Dave

I have never tried to post a new thread in HMEM so just hope this is read.

I have recently needed to drill small holes (5/16th) in Mild Steel. But I have found that although almost all drill with ease I have recently had a number of holes that just will not allow the drill to penetrate. I think I have totally ruined some 5 or 6 drill bits.

Is the problem poor quality steel or is it just me ?
Any assistance in giving me a solutioin would be greatfully received

 

[cheepo45]

Drill with a smaller drill first, slow the drill RPM down, and use some oil-should work fine.
Scott

 

[Tim Wescott]

It depends on where you're sourcing your steel. My dad once found a ball bearing embedded in some "mild steel" 2 x 2 x 1/4 inch angle iron. It was only slightly deformed, and had clearly survived whatever remelt was done when the mill turned some scrap into some angle iron.

It ruined a nice saw blade, too.

This was 20 or 30 years ago, but I doubt things have changed.

 

[IanN]

I have never tried to post a new thread in HMEM so just hope this is read.

I have recently needed to drill small holes (5/16th) in Mild Steel. But I have found that although almost all drill with ease I have recently had a number of holes that just will not allow the drill to penetrate. I think I have totally ruined some 5 or 6 drill bits.

Is the problem poor quality steel or is it just me ?
Any assistance in giving me a solutioin would be greatfully received

Hi,

What are you using for cutting fluid?

Ian

 

[SmithDoor]

I have worked over 40 years in steel. We drill thousands without cutting oil in A36 steel.
If has problem it was drill bit.

Dave

Hi,
What are you using for cutting fluid?

Ian

 

[TonyM]

Are you feeding by hand? It may be that the drill is being damged breaking through. If the bit snatches at the end check the tip before trying to drill the next hole.

 

[Ozwes007]

Another issue we have had at work is Chinese steel having hard spots in it. You see them when you are machining and when drilling or milling. Mild steel and 1020 grades are the worst for it.

 

[johwen]

Can You send a photo of the cutting end of the drill before you start drilling and after the drill has refused to cut and we may be able to determine the answer to the problem? Are they new drills or have they been sharpened before use?

 

[Richard Hed]

Thanks, I hear what you say, but if you are grilling 2 foles adjacent to each other, with a long pause between each I just do not understand why hole A drills easily, and hole be will not. to the extent of totally ruining the drill bit.
I have a friend who has just had the same exoerience (he is a trained engineer). He needed to drill 3 holes in part of a garage door. holes 1 and 2 no problem. but hole 3 +was so hard that even a cobalt drill found it hard going.
His opinion is that the scrap yards that remit scrap to India are not careful in their sorting, which means when the scrapis re-melted it is muddled up with various grades

I workt for a place that bought metal sheets from Maylaysia. The Steel was not properly melted and we would actually find bolts sticking out of the sheets that were partially melted. The bolts, of course, were a different grade with different alloys and etc.

 

[Gabe J DiMarino]

If your drilling mystery metal , I would pre -drill and use an appropriate rpm for the size drill then try with a sharpened 5/16 drill and some lube. The larger the drill the slower your rpm should be.

 

[davidyat]

I went through the same problem a while back. My mentor asked me what I was doing. He found out that I was drilling a small hole TOO slowly and was getting "work hardening". When I started to drill with a faster hand input, it drilled very easily.
Grasshopper

 

[William May]

I avoid all mystery metal. When someone offers me some steel, I usually tell them that I have all I need of that particular material. It is much cheaper and faster in the long run to buy a known piece of steel to a spec, and then machine it. I still have some metal stored in my garage that someone gave me, that is nasty in every way. It is very difficult to machine, hard to drill, etc, etc. In fact, I'm glad you reminded me of it, because it is going into the semi-annual bulky trash pickup this year.
The situation is different if you have to work on an existing part. I would slow the drill down, use a good quality drill bit and cutting oil, and see what happens. If the material is thick, or the hole is large diameter, drill a pilot hole first.
If you buy scrap metal to machine. you will find you are generating a lot of scrap metal, too.

 

[L98fiero]

I went through the same problem a while back. My mentor asked me what I was doing. He found out that I was drilling a small hole TOO slowly and was getting "work hardening". When I started to drill with a faster hand input, it drilled very easily.
Grasshopper

That's probably the key, when drilling with a hand drill the speed is often too high or the feed too low or both and the drill gets dulled, then when you try to drill the next hole it work hardens the bottom of the hole so even a new drill is difficult to start.
Stainless in particular is an issue, slow speed and fast feed and a cutting fluid is the way to go and don't let the drill rub, it work hardens and then it's difficult to get the drill started cutting again. I had someone try to drill a 5/16 hole on 304 stainless at 750 RPM and the cutting edges broke down and left particles in the stainless. The drill didn't stick in the hole but there was no finishing that hole to depth, throw it away and try again, this time the right speed and feed.

 

[willray]

I have recently needed to drill small holes (5/16th) in Mild Steel. But I have found that although almost all drill with ease I have recently had a number of holes that just will not allow the drill to penetrate. I think I have totally ruined some 5 or 6 drill bits.

Is the problem poor quality steel or is it just me ?

You need to tell us what you're actually drilling, what you're drilling with, and what kind of holes you're drilling.

"Mild steel" - if it's really mild steel and of any reasonable quality - really won't harden much, almost nomatter what you do to it.

"Mild steel" as found in mystery-metal chunks of various already-existing implements, like bed frames and other structural bits that manufacturers use as parts of their products, can be just about anything, and of wildly varying composition from chunk to chunk, or even from spot to spot on the same piece. As has been mentioned by previous posters, the same problem exists in "Mild steel" from less-reputable reprocessors (gone are the days of quality fresh "new" steel straight from the ore, as was produced by USS/etc back when first-world countries actually made things rather than ordering them from China).

Likewise, what variety of drill bit, and how you're driving it, make a huge difference in the drillability of 5/16ths holes.

With a drill press, and a decent quality HSS bit, you should be able to put tens to hundreds of 5/16ths holes in real mild steel, without coolant, and without drilling a pilot hole. More, if you're drilling blind holes.

Try doing 5/16 thru-holes with a hand-drill in mystery-metal "mild steel", pilot-hole or no, and like as not, you'll hit a hard bit of skin coming out of the far side, wobble the drill motor because of the change in torque, and rip a lip off the bit. Fail to notice that, and your next hole goes to crap.

Try doing any of this with less-than-quality bits, and all bets are off. You may get 200 perfect holes, or you may get 2 decent holes and then for no detectable reason the thing turns into a noodle in the chuck. Buy your bits from Hobo-fright, TSC, or cheap stuff from Amazoon, and you'll be reasonably lucky if all of the drills are actually "sharpened" such that the cutting edge contacts the material before the relief behind it. Surprisingly, if you're ham-handed enough even with those potato-mashers, and you happen to have lucked into one of the hard ones, with a drill-press it will sometimes "drill" for a while by turning the metal underneath it into pudding and pushing it out of the way. Eventually you soften the tip of the bit enough that that stops working too.

So - more information - maybe a photo of the holes you've drilled (front and back), and photos of the damaged drill bits, and then hopefully give you some help that's not just guesses!

 

[Cogsy]

Cogsy, I have just noticed that you live in WA. I was there from 1962 to mid 1970, i was in Real Estate. Amongst many other propertie i for a perion owned Bay View Mansions in Claremont. Whre do you live and what do you do, or did do ?
Best wishes Malcolm Farrant (Roskrow)

I live in the foothills in the Armadale area - a long way from the expense of Claremont. I'm still working (I'm only mid 40's) as a research physicist currently. Not good money but incredibly interesting (to me anyway).

 

[SmithDoor]

A photo may help.
Odds are it is the drill bit.
Even if it is a harder steel the drill bit would do job.
They have made past low cost drill bits they look just like a good drill bit. But they will not drill steel.
At one time in my life I was buying drill bits gross at one and found a great price was bad drill bits.
Most drill bits die to the person drilling the hole.
Did have that lasted till we could not sharpen the drill aka to stub.
The steel that we drilling was grade 45 it is harder than A36.

Dave

Can You send a photo of the cutting end of the drill before you start drilling and after the drill has refused to cut and we may be able to determine the answer to the problem? Are they new drills or have they been sharpened before use?