How do you drill hardened steel?

[DennisThornton 4,769]

[WVHillbilly520H 10,369]

Not knocking those bits as I have not experience with them myself, but here are "machinists" takes on them around 10 years ago...

https://www.practicalmachinist.com/vb/general/anyone-tried-bad-dog-drill-bits-236059/

[8ntruck 6,358]

Come to think of it, you could use copper or brass tube of the proper diameter and valve grinding compound to get through hard steel.  Might take a while.....

[ebinmaine 62,982]

1 minute ago, 8ntruck said:

Come to think of it, you could use copper or brass tube of the proper diameter and valve grinding compound to get through hard steel.  Might take a while.....

Can you elaborate on that please?

[8ntruck 6,358]

Mount the proper size copper or brass tube in a drill press, apply valve grinding compound to the working end, run at a slow speed so as not to fling the compound all over creation, feed into the steel.  Refresh the compound as necessary.  

 

The theory is that the abrasive particles will get imbeded into the brass or copper making it act like a grinding wheel or a lapping tool.  I've read this in several sources, but never tried it.  Some sources say to make 2 axial slots in the tube, probably to give the swarf somewhere to go or to provide a supply of compound to keep it cutting.

[DennisThornton 4,769]

36 minutes ago, WVHillbilly520H said:

Not knocking those bits as I have not experience with them myself, but here are "machinists" takes on them around 10 years ago...

https://www.practicalmachinist.com/vb/general/anyone-tried-bad-dog-drill-bits-236059/

I'm not going to defend the negative comments within, only that I've seen and tried them at several shows but it seems the only time I used one at home I broke it, so other than seeing and trying them at the shows, I can't offer much.  I gather that it is important to operate as instructed but obviously I never got good at it. 

 

Sidenote:  I will say that their Biter nibbler is incredible!  Only used it a few times for small projects so I don't know how long it will hold up but it will do some crazy cuts!

[lynnmor 6,762]

29 minutes ago, 8ntruck said:

Mount the proper size copper or brass tube in a drill press, apply valve grinding compound to the working end, run at a slow speed so as not to fling the compound all over creation, feed into the steel.  Refresh the compound as necessary.  

 

The theory is that the abrasive particles will get imbeded into the brass or copper making it act like a grinding wheel or a lapping tool.  I've read this in several sources, but never tried it.  Some sources say to make 2 axial slots in the tube, probably to give the swarf somewhere to go or to provide a supply of compound to keep it cutting.

I would cancel all appointments for the next six months as well.

[ol550 825]

I have used this to drill leaf springs that I use for snow plow edges.

  Cobalt bits and cutting oil.

[DennisThornton 4,769]

1 hour ago, ol550 said:

I have used this to drill leaf springs that I use for snow plow edges.

  Cobalt bits and cutting oil.

Man!  I've been looking for years and NEVER seen one for sale!  Bet I still haven't...

Probably should just plain on making one!

How do you straighten the leaf springs?

[ol550 825]

1 hour ago, DennisThornton said:

Man!  I've been looking for years and NEVER seen one for sale!  Bet I still haven't...

Probably should just plain on making one!

How do you straighten the leaf springs?

 

25 Ton press.  Have to be careful when you get close to the tie bolt holes, have broken some there.

[DennisThornton 4,769]

2 minutes ago, ol550 said:

 

25 Ton press.  Have to be careful when you get close to the tie bolt holes, have broken some there.

Certainly seen broken leaf springs and some sagging but I never thought I could bend them on a press.  And you've made 4ft long edges?  What trucks are good choices?

[ol550 825]

37 minutes ago, DennisThornton said:

Certainly seen broken leaf springs and some sagging but I never thought I could bend them on a press.  And you've made 4ft long edges?  What trucks are good choices?

I have been using GM springs as that's what I have around.  Think they are 2 1/2 wide.  Have welded some together to make the longest a 6 footer.

[WVHillbilly520H 10,369]

1 hour ago, DennisThornton said:

Certainly seen broken leaf springs and some sagging but I never thought I could bend them on a press.  And you've made 4ft long edges?  What trucks are good choices?

 

1 hour ago, ol550 said:

I have been using GM springs as that's what I have around.  Think they are 2 1/2 wide.  Have welded some together to make the longest a 6 footer.

That's what dad used on the rear scraper blades he made many years ago, instead of drilling we just welded it the original 1/4" CRS/HRS edge under the bolts... Start in the center then using C clumps as you got out the ends definitely wears better than plain CRS/HRS. and when it does grind off welds flip and reweld this has been on it for over 20 years through hard sandstone, limestone base and packed clay.

Edited March 10, 2021 by WVHillbilly520H

[ranger 1,618]

I have a set of drills bought at a show many years ago. I’ve messed up one, the 8mm. I’ve drilled through files, stainless steel and leaf springs. They really want to be used in a drill press to keep the pressure on to cut and minimise slipping, also you shouldn’t drill a pilot hole, that is the quickest way to ruin them apparently. I drilled the cast iron “Aldi” weights I used for wheel weights with the 12mm one, it went through as if it was butter!

Doug.

[Zeek 2,284]

Where does @buckrancher weigh in on this? He's a machinist 

[lynnmor 6,762]

@ebinmaine have you tried to drill with a standard HSS drill bit yet?  If you knacker the bit, I will send you a replacement if needed.  Hopefully you have a drill press, hand drilling ain’t pretty sometimes.

[ebinmaine 62,982]

21 minutes ago, lynnmor said:

@ebinmaine have you tried to drill with a standard HSS drill bit yet?  If you knacker the bit, I will send you a replacement if needed.  Hopefully you have a drill press, hand drilling ain’t pretty sometimes.

 

I did, yes. 

And thanks very much for the offer. 

 

It did great for all of one hole and part of another. Then stopped and (I think) work hardened what was already harder than it should have been able to take. 

 

I tried SEVERAL other bits of 4 sizes and nothing I have currently will even begin to bite. 

 

I'm hoping to get it to our friend's shop this weekend but if I have to wait again I may go to the big box store and get some Cobalt bits. 

 

Perhaps if I heat that specific hole before drilling I can get a bite again. 

 

[lynnmor 6,762]

I would not heat the steel, there is no way of knowing how it was hardened and you might make it worse.  When you make your next attempt, remember what I said about making it cut or get out, in other words, pee or get off the pot.

[WVHillbilly520H 10,369]

4 hours ago, lynnmor said:

I would not heat the steel, there is no way of knowing how it was hardened and you might make it worse.  When you make your next attempt, remember what I said about making it cut or get out, in other words, pee or get off the pot.

I see we concur on the heating of hardened steel, as I am sure you are quite aware, but to let others know that were/are not in the machining/tool & die field, to correctly aneal hardened tool steels, 

The hardened work piece needs to be put in a correct kiln/oven and "baked" at a predetermined temperature for the material (A6 D2 ect) for X amount of time then do the repair or machining work, then back to the oven  to harden and temper again, torching small spots usually causes the "glass" effect where now it has become to brittle/fragile and shatters. 

We used "spade" carbide bits more than twist bits for reworking hardened steels, we used a lot of Thompson shafting and induction hardened linear bearing rails for the machinery in the factory (so I learned this as OJT and no books or classes, either you did it right or production didn't run), you had to be careful when drilling this type of material as soon as you "break" through the hard part the drill would chip or break as it entered the softer/gummy unhardened portion if drilled to deep that's why I suggested medium pressure and down/retracts sequence, and definitely a drill press.

Edited March 12, 2021 by WVHillbilly520H

[WVHillbilly520H 10,369]

@ebinmaine spade bit...

https://www.knifekits.com/vcom/carbide-spade-drill-375-p-16347.html

[DennisThornton 4,769]

1 hour ago, WVHillbilly520H said:

@ebinmaine spade bit...

https://www.knifekits.com/vcom/carbide-spade-drill-375-p-16347.html

I LIKE it!

[8ntruck 6,358]

2 hours ago, WVHillbilly520H said:

I see we concur on the heating of hardened steel, as I am sure you are quite aware, but to let others know that were/are not in the machining/tool & die field, to correctly aneal hardened tool steels, 

The hardened work piece needs to be put in a correct kiln/oven and "baked" at a predetermined temperature for the material (A6 D2 ect) for X amount of time then do the repair or machining work, then back to the oven  to harden and temper again, torching small spots usually causes the "glass" effect where now it has become to brittle/fragile and shatters. 

We used "spade" carbide bits more than twist bits for reworking hardened steels, we used a lot of Thompson shafting and induction hardened linear bearing rails for the machinery in the factory (so I learned this as OJT and no books or classes, either you did it right or production didn't run), you had to be careful when drilling this type of material as soon as you "break" through the hard part the drill would chip or break as it entered the softer/gummy unhardened portion if drilled to deep that's why I suggested medium pressure and down/retracts sequence, and definitely a drill press.

It is not the heating that causes the steel to get harder and more brittle so much as how fast the piece is cooled.

 

Heating the piece to a bright cherry red or orange, then dunking it into water will make the material hard and brittle.  Working from memory, to anneal a piece of steel, it needs to be heated to about the same temperature it was originaly quenched when hardened, then let it cool SLOWLY - most often done by letting the heat treat furnace cool slowly.

 

The following can be classed as interesting summarized background info I learned in the 400 level metallurgy course many decades ago:

1055 steel is a high carbon steel without any other alloying elements.   More carbon in the steel, the harder it can get - at the cost of becoming brittle. The steel hardens because quenching traps carbon atoms in the face of the iron crystals instead of in the inside the iron crystal. 

[WVHillbilly520H 10,369]

6 hours ago, 8ntruck said:

It is not the heating that causes the steel to get harder and more brittle so much as how fast the piece is cooled.

 

Heating the piece to a bright cherry red or orange, then dunking it into water will make the material hard and brittle.  Working from memory, to anneal a piece of steel, it needs to be heated to about the same temperature it was originaly quenched when hardened, then let it cool SLOWLY - most often done by letting the heat treat furnace cool slowly.

 

The following can be classed as interesting summarized background info I learned in the 400 level metallurgy course many decades ago:

1055 steel is a high carbon steel without any other alloying elements.   More carbon in the steel, the harder it can get - at the cost of becoming brittle. The steel hardens because quenching traps carbon atoms in the face of the iron crystals instead of in the inside the iron crystal. 

Yes sir, but from actual in shop experiences heating with the torch vs controlled oven heating, then like you said bring to a very slow cooling cycle, are most of us on the day to day going to follow that process??? Another way to slow the cooling time is a bucket of lime, if a heated part is buried (not just covered) it will also help with controlling in how brittle vs how "tough" and part becomes in the heat treat process.

The reason I mentioned all that before was even being in the tool and die shop things got rushed and some others just didn't take the time do the job correctly, and I have seen the bad results more than the good.

[ebinmaine 62,982]

10 hours ago, WVHillbilly520H said:

@ebinmaine spade bit...

https://www.knifekits.com/vcom/carbide-spade-drill-375-p-16347.html

Can that be used with a starter drill in an already open hole? Or does it need to do its own drilling with the point?

 

 

[WVHillbilly520H 10,369]

1 hour ago, ebinmaine said:

Can that be used with a starter drill in an already open hole? Or does it need to do its own drilling with the point?

 

 

I have used it both ways, and to drill out broken taps but that is another topic.

Edited March 12, 2021 by WVHillbilly520H