Problems with Steel

[clockworkcheval]

Of course I concur with all common sense comments mentioned above. However sometimes you have no choice in the material you have to drill and it won't work with HSS. What oftentimes helps is to take a concrete drill, which has a carbide tip. The smallest size I can get is 3 mm (about 1/8th). This I grind as a steel drill. I use it as a starter for though materials (also for hard skins of cast iron) with a lot of pressure, feed, cutting oil and moderate speed. In most cases it will get me a reasonable starter hole which I can then follow up with regular HSS drills.

 

[comstock-friend]

Check feeds and speeds for the size drill you use (just about all my holes are drilled on the Bridgeport, my import drill press is generally much too fast). Avoid cheap Chinese and Indian drills. Do not expect things like angle iron taken from bed frames to be 'mild steel'. Material with a pedigree is the way to go, A36 hot rolled, 1018 cold rolled at a minimum (or UK or ISO equivalents). I'm hard pressed to use anything other than free machining leaded steel or 1144 stress proof for good surface finish, strength, etc (or drill rod=silver steel).

John

 

[OrangeAlpine]

The problem with drilling closely spaced holes sounds like the steel is hardening from heat generated from drilling the previous holes. This is real easy to do with air hardening steel or sometimes with low quality steel made from anybodies guess feed stock. Lately I've become a real fan of low rpm, high pressure drilling. Seems to avoid a lot of problems.
Bill

 

[Gabe J DiMarino]

You can pretty much tell what it is by spark testing and the type of chips its makes . After cutting metal for 35 years you just know.

 

[gunner312]

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

IMHO, after 30+ years as a Machinist, I have found that most of the time drilling problems are caused by, 1 drilling too fast, 2 drilling with a dull drill bit. 3 not using drill lube. AND again pushing the drill to fast/hard. Use your speeds and feeds, drill slower and with less pressure. Let the drill do the work and SHARPEN YOUR DRILL BIT!!.

 

[terryd]

IMHO, after 30+ years as a Machinist, I have found that most of the time drilling problems are caused by, 1 drilling too fast, 2 drilling with a dull drill bit. 3 not using drill lube. AND again pushing the drill to fast/hard. Use your speeds and feeds, drill slower and with less pressure. Let the drill do the work and SHARPEN YOUR DRILL BIT!!.

Using too little pressure can also cause problems. The drill can then rub which causes it to overheat and lose it's edge. Unless you calculate speed/feed rates (assuming of course a sharp drill) it is a matter of 'feel' which I developed in my 50+ years of experience,

Best regards,

TerryD

 

[Roskrow]

You have all sent me very helpful suggestions, for which I thank you. Alas I have now throne away the ruined bits, I think the comments on over hear and gardening are very relevent.
For 5/16 I was dril

 

[Roskrow]

I would like to say a BIG thank you to so many of you who have tried to assist me.

It seems the errors are almost certainly caused by myself.

I am 83, and I confess not an exprienced lathe etc user, but I do learn from my many errors !!

I try and purchase really good quality drill bits, but no,I do not re-sharpen them.

It seems I need to learn what speed I should be drilling. I seldom need holes any bigger that 1/2 inch. Perhaps there is a chart somewhere that would guide me.

Again many many thanks for all your wise words.
Malcolm arrant

 

[goldstar31]

Perhaps Tubal Cain's book 'Drills, Taps and Dies' would be of use.

I've no idea of the price now because mine is on file now.

When one gets to 90, one gets cluttered with things.

Actually my son is in quarantine from a visit to France and wants to buy and re-build a Deux Chevaux and I said that he should learn to plug weld onn my little Mig. Lots of holes.

Take care


Norman

 

[gunner312]

Using too little pressure can also cause problems. The drill can then rub which causes it to overheat and lose it's edge. Unless you calculate speed/feed rates (assuming of course a sharp drill) it is a matter of 'feel' which I developed in my 50+ years of experience,

Best regards,

TerryD

Yes that's true, but using too much pressure causes more wear on the drill margins and dulls the drill quickly. Also can cause the point to "walk".

 

[gunner312]

I would like to say a BIG thank you to so many of you who have tried to assist me.

It seems the errors are almost certainly caused by myself.

I am 83, and I confess not an exprienced lathe etc user, but I do learn from my many errors !!

I try and purchase really good quality drill bits, but no,I do not re-sharpen them.

It seems I need to learn what speed I should be drilling. I seldom need holes any bigger that 1/2 inch. Perhaps there is a chart somewhere that would guide me.

Again many many thanks for all your wise words.
Malcolm arrant

Malcolm,

You really should learn to sharpen your drills, it's really a very easy skill to learn. I have a Darex drill sharpener that I bought 20 years ago and I am sure that it has saved me its cost many times over. However, before I bought it I sharpened my drill bits by hand and eye. I still do on occasion (when I'm too lazy to set up the drill sharpener). There are inexpensive drill sharpener attachments for your shop bench grinder that are readily available and can save you time and money. I am 74 and still making models and toys as my wife calls what I make.

 

[kwoodhands]

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

I agree, I had a problem with a steel plate that needed 16 3/8" holes in a close circular pattern. I got thru the first plate but wasn't easy. My mothers side of the family are machinists. I gave a cousin a call.
He said I may have been work hardening the plate. He suggested that I drill 4 holes opposite each other. Then 4 more opposite each other. Repeat til the 16 holes are complete, This lessens the chance of work hardening because the heat from drilling has a chance to cool.
If the holes were spaced further apart then this may not be necessary.
Tom's suggestion worked. I actually tested his theory on the last of 8 plates by trying to drill the first two holes close together. Drilling went hard like I expected. Finished drilling Tom's way, no problems.
I used plumbers cutting oil, the dark stuff and Cleveland brand drills.
mike

 

[SmithDoor]

Photo of poor drill bits
They just like any other drill bits. But try drilling steel they will fail.
About the only thing this group drills can drill is pine wood.
Only have them as reminder of bad drill bits.

Dave

 

[goldstar31]

After reading the many comments and then my own and think. I am. a guy with 3" division plates with rows and rows of holes
Two comments have to emerge. Mine have been drilled in free cutting mild steel and the holes and those are drilled with stub drills.

Writing as a 'none engineer, we seem to have forgotten that a drilling machine, a mill and a lathe are cutting in a circular pattern with similar tools------ but to get anywhere the cutting speeds of all of them have to be adjusted for the Diameter of the drill as well s the material.
Quite simply- IMHO, we drill too fast into cheap jack metal with equally cheap jack drills------and naturally, belly ache.
Again, no one has deigned to mention the old Slocombe drills/centre drills.

I had a daft one the other day. I was drilling a 7mm hole into an 38mm/1.5" lump. It ended up as a rattling fit and two points arose. The first was a worn out drill chuck and the lips of the drill being unequal.

My thoughts , good folks, but I bought TWO precision drill chucks------ and thoughts about boring with a properly fashioned boring bit- instead.

My musings-- of course

 

[terryd]

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,

Probably trying to teach my grandmother to suck eggs but here goes - Always start with a centre punch mark, this not only locates the hole but gives a place for the 'land' of the drill (the inevitable flat across the end of the drill between the flutes) which allows the cutting edges to start cutting. If you try to cut too slowly or too fast (too little or too much pressure on the drill) the 'land' will rub on the work and overheat as it cannot do any cutting.

After centre punching I suggest that you drill a pilot hole big enough to accommodate the 'land' of the 5/16" drill, this allows the cutting edges to do their work without any rubbing, Keep a steady pressure on the drill - enough to keep it cutting and no more. I use my drills mostly dry these days as I'm now in it for a hobby but in industry and school workshops we used a cutting fluid but HSS drills - which are the only ones I use - don't really need it in mild steel. I have a set of HSS drills from 0.5 to 10 mm x 0.1mm i.e. 100+ drills. I've had these for almost a decade and only had to replace a few small drills through breakage (or loss!!) and one 3.2 mm drill lost it's edge. When dull I hand sharpen which I learned to do almost 60 years ago. I now use 4 facet sharpening and thin the web to reduce the 'land' on the larger drills.

TerryD

 

[terryd]

After reading the many comments and then my own and think. I am. a guy with 3" division plates with rows and rows of holes
Two comments have to emerge. Mine have been drilled in free cutting mild steel and the holes and those are drilled with stub drills.

Writing as a 'none engineer, we seem to have forgotten that a drilling machine, a mill and a lathe are cutting in a circular pattern with similar tools------ but to get anywhere the cutting speeds of all of them have to be adjusted for the Diameter of the drill as well s the material.
Quite simply- IMHO, we drill too fast into cheap jack metal with equally cheap jack drills------and naturally, belly ache.
Again, no one has deigned to mention the old Slocombe drills/centre drills.

I had a daft one the other day. I was drilling a 7mm hole into an 38mm/1.5" lump. It ended up as a rattling fit and two points arose. The first was a worn out drill chuck and the lips of the drill being unequal.

My thoughts , good folks, but I bought TWO precision drill chucks------ and thoughts about boring with a properly fashioned boring bit- instead.

My musings-- of course

Hi goldstar,

I no longer use Slocomb drills for anything other than on the lathe when intending to turn between centres Instead I use spot drills. I was recommended to these by the late John Stevenson when I used to correspond with him. They are excellent and have much smaller lands than Slocomb drills.

TerryD

 

[goldstar31]

Hi goldstar,

I no longer use Slocomb drills for anything other than on the lathe when intending to turn between centres Instead I use spot drills. I was recommended to these by the late John Stevenson when I used to correspond with him. They are excellent and have much smaller lands than Slocomb drills.

TerryD

I take and appreciate your remarks -- and of course Sir John's- RIP.

I think that I'm somewhat old fashioned-- the understatement of the decade.

I have quite a lot of the things- and being Scots and born on the steps of the synagogue, retained the bag of sweets on our engagement, keeping them for the children. They in their turn- well you know the rest.

My son still has the claw hammer which my father made on the anvil- before WW2-- and I have my late wife's Mickey Mouse gas mask and my father in laws service respirator and tin hat. You never know when things like that will be needed.
I'm still wearing a solid gold Waltham gents fob watch which had never run since 1938-- or before.
I'm careful-- not mean.
Regards

N

 

[terryd]

Hi Goldstar,

Like you as an old timer, I also usedtools which had been passed down to me from father and grandfather. but unfortunately I had a devastating garage/workshop fire which destroyed all of my tools and machinesas well as my sailing dinghy and 2 Triumph Stags one of which I was rebuilding. So as you see I had to re equip after rebuilding, fortunately I had very good insurance which was some compensation and was able to completely replace almost everything. The main road past my bungalow linking to the M1 was blocked for 4 hours by 2 of the three fire appliances which attended. I alsways reccomend that folks check their insurance policy as some only offer small amounts for contents of detached buildings, around 2 -5000 pounds whereas mine included full replacement costs. Was I glad that I hadn't gone for those 'cheaper home insurance' offers.

My own old gold watch passed down from my grandfather (a Benson, a present when he retired) is still working and I wear it occasionally to remind me of him in place of my own Rolex.



The bottom left picture is the remains of a Boxford CSB on stand with splashback.

TerryD

 

[goldstar31]

I can sympathise with your loss as my wife died without warning almost 5 years ago on September 4th.
The rest was unimportant in comparison

So Best wishes

Norman

 

[L98fiero]

I no longer use Slocombe drills for anything other than on the lathe when intending to turn between centres Instead I use spot drills. I was recommended to these by the late John Stevenson when I used to correspond with him. They are excellent and have much smaller lands than Slocombe drills.

Another point about the spotting drills, use 135 or 145 degree instead of the 90 degree spot drills, they center the drill better. When you use the 90 degree spot drill you get the same problems as with the combined drill and countersink(center drill/Slocombe) in that there is no support from the chisel edge/point of the drill and you can get chatter and an out of round and oversize hole at the start.
Another side note is how to drill a ROUND hole in sheet metal. Often, when you drill sheet metal the hole will come out almost triangular, a way to prevent that is to put a small patch of cloth under the drill, it should be 2 or 3 layers thick depending on the cloth, and drill through that. When it was shown to me there was no rationale behind it just that it worked but I think the idea is that it supports the drill point as it goes through the sheet.