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drilling hardened steel with bits


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Everything is finnihed i mean about heat treat. Knife made from leaf spring i think its is too hard to be drilled, can i skip again anealing or normalisation (i think i get good quality on blade) and doing that again heat treat might ruin it.

Well question is how to drill that i tried and drilled 90 percent of one small hole and dril bitt wont come anymore deeper.

And one question two how does temper travel trough blades. iam not still sure how it does horizontaly or verticaly, and what efect it, does it effect how you dip your blade in liquid (oil water) how will temper appear

Differentially_tempered_chisel.jpg  for example this screwdriver "chisel" or this knife hqdefault.jpg 

well thats two questions.
how to drill hardened steel and how does one control temper "moving" does it matter how you dip steel in quench.Well third one after i polish grind blade and put it in fire then quench it i have issues sometimes to see temper color becasue of scale that is blue grayish collor and it form.

And if i will grind it i will loose temperature.

Thanks 

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If you are drilling the tang you can draw the temper on the tang a lot with the blade section immersed in water---they tang does NOT need to be hardened.

I drilled a pivot hole using solid carbide drill bit and a good drill press----hand held drills will just shatter the expensive bits.

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I anneal my tools, then drill holes, then heat treat. Then there is no problem. To solve yours, wrap your blade in a rag and keep it wet. then normalize your blade. start over on your heat treat. anneal the whole thing, drill holes, finish heat treat, and call it practice.  ;)  

I'm not sure I understand your second question, but I think it has to do with a differential temper, or reserve heat temper, one and the same. I will refer to your chisel. It looks like thats what you have done. Heat to critical temp back about where the blue starts, quench the tip vertically up and down about to where the handle begins. polish quickly and watch the colors run, like you have done. have a tin can with water as deep as you want to stop the color run. 

It looks like your tool is a chisel and the profile is what I use for a cold chisel. Most of my hand tools are from coil spring. A light straw or even a dark straw is too hard for a cold chisel and you may get chips on the edge. For my cold chisels, I draw them to the color just in front of the blue. I want this color max up to the top of the edge bevel. half way up is better. 

I always "dip" my tools in vertically, and move them up and down. this keeps bubbles off the steel and prevents a line between hard and all else. this can cause a stress crack. if you move it up and down about a half inch, you get a band, not a line where the quench stops. Don't go side ways(horizontal?) because one sides cools faster and will warp. When you quench your tool, knife or chisel, think having the sharp end follow the path of least resistance and thin to thick. So a chisel can go straight vertical while you might want a knife to go in point first then follow the profile thin to thick while rotating your knife tang down the deeper you go.  

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A trick my grandfather taught me for drilling hardened steel. Take a round piece of mild steel the right size for your drill bit and grind one end rounded or take an old drill bit and chuck it up backwards so the tang is out of the drill press chuck. Run the press at a fairly high speed and apply pressure to the steel like you were drilling it. In no time the steel will turn red hot then drill the hole at black heat.

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Good idea. Thats sorta how I do it on thin stuff that hardens when I've drilled it,,, wrong... but I use my small welding tip for the spot heat. I too let it cool, then drill. Its sorta normalized and drillable.

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Maybe my mistake or lets say disadvantage is that i use regular hand drill instead of drill press.
Maybe i dotn have enaugh preassure to drill steel in first place?

When we were at school it was so easier to drill metal using drill press than comparing to this drill that you need lean on it to dirll (sometimes i even break  bits.


If nothing will help i would have to make small punch for that hole and punch it out hot, i have center punch that i bought but i feel like i will ruin it temper if i try it on hot steel (to punch out hole)

And if i  choose this way of "punching out hole" drifting or how its called i know i will deform handle a bit, it wont be precise and i will have to make thin piece of round steel welded or fastened somehow so it dont transfer heat to hand while i drift it.

Anvil good idea i forgot that i can even melt down with rod and enaugh amparage that hole..

 

 

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You can run the hardness out of the spots you need to drill spinning a piece of round stock or reversed old drill bit with a hand drill, it will just take longer, just lean on it a little. Don't push as hard as you can be patient it'll get hot for you.

When you drill the hole use a slow rotation speed and increasing pressure until you're sure the bit cuts, then drill it like you normally would. 

If it still doesn't drill use the round stock friction trick again and keep it red hot longer. I've never had to do it twice but I've been doing it since I was pretty young and you know what they say about practice.

If you still can't drill it I'd anneal the whole blade, drill the tang and repeat heat treatment. That way you won't have to worry about a transition between hardened blade and annealed tang like you would if you just normalize the tang. 

Next time you make a knife remember to drill the holes before heat treatment. Keeping the steps in order is important, you can spend more time and effort fixing a mistake than you would have invested in the whole project. We've all been there it's part of the learning curve.

Boy, a spot welder would work a treat. I've never done it that way.

Frosty The Lucky.

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I’ve been making knives from industrial size band saw blades lately and found if I’m careful not to overheat the metal when cutting and grinding, I don’t have to heat treat the blade. It’s perfect as is for some kitchen knives. I found a handful of solid carbide bits in a junk store for 2 bucks. They drill the holes just fine.

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  That has been so long ago all I remember was destroying every bit I tried.  It was a power hacksaw I built which eventually wore itself to pieces after several rebuilds.  I found a cheap used Enco horizontal bandsaw and never looked back.

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Frosty i  used to work with mild steel and even grinder disc was "telling" me it will be tough, you can run out of small discs in seconds when you cut it, thats why i have "axe" now that i will use to cut hot steel wich is slower process if it is not heated enaugh.

I made that axe using old axe head and welded some leaf spring to it.

I think it is strong enaugh to work, hey it can cut nails on anvil and i think it stay in good edge shape . Thats how that steel is hard (or i quenched it a good) still heat treatment is hocus pocus for me if do it good i did it by luck.

In theory i know how its done but practice is something else.

Call me lazy but i used arc /rod welder and drilled some a litle bit unacurete rod and one tip too, you can use old electrode "done that in school" to make rivet out of it it is not that strong  but its easy to be shaped instead using nail or forging brand new rivet out of new material.

I cant remember what we build but we used that for something small.

Maybe I am not best craftsman but sometimes i just want things to be done in shorcut , and sometimes i want to do it slowely it depend on mood i guess.

 

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What your first paragraph tells me is the steel you made the knife from is an abrasion resistant alloy and will eat drill bits no matter what. There may not be a good way to drill holes in it without spending the money for diamond drill bits. Abrasion resistant steels are used for things that rub on through things like gravel, sand rocks, etc. so it contains ingredients like tungsten carbide particles. 

We're not criticizing, you have a problem and we're making suggestions to solve it, that's all. It's good for everybody, several different tricks were discussed so everybody gets to learn. One trick I just learned might work when the one I usually use doesn't. Everybody gains.

We appreciate good questions Nat, thank you.

Frosty The Lucky.

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  • 2 weeks later...

Don't use a drill geared for drilling wood for drilling steel.  My drillpress is currently set for drilling steel and is much faster than a hand crank.  If I need to drill wood I use a hand electric drill.

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I keep the drive belts on my drill press set for the lowest metal drilling speed (about 350-500 rpm IIRC).  That speed drills wood just fine if a bit slower than the higher rpm.  If I were doing a lot of wood drilling I'd open up the box and readjust the belts and pulleys but that is too much hassle for a few holes.

"By hammer and hand all arts do stand."

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My El Cheap'O,($39+ tax) Bob's Closeout 16speed drill press has a spring loaded idler pully making changing speeds easy so I don't mind adjusting it. I bought the thing probably 40 years ago as a temporary piece of equipment but it's worked flawlessly so . . . 

A few summers ago I saw a dream drill press at a yard sale. 2 1/2hp 120-240v single phase with a infinite torque converter, fluid drive. It would turn slowly enough to use it for tying flies or 2,200rpm. With thrust bearings so it was suitable for light milling. $50. Unfortunately it was badly rusted and the motor wouldn't even hum. I've used infinite torque converter drill presses and I would've been willing to spend considerable money and time restoring it but she was pretty shot from sitting in the weather.  It was enough to make a boy cry. 

Frosty The Lucky.

 

 

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  • 3 weeks later...

The standard reply to "How big should my shop be?" is: 2N where N is he size you currently have. (Of course when you expand; then N is the size of your expanded shop and you should start planning the next extension...)  I started with 20'x30', doubled it to 20'x60' and would really like to add a truckport on the end...

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10 hours ago, Frosty said:

Looking for more space?

Hmmm?

Frosty The Lucky.

Well my bench grinder is on workbench now, some vise and I think one shelf that hang on to it so yeah.

 

It's like 6 foot length and 2 foot wide.

On other side of wall there is shelf .

Well Iam jack of all trade in 10 by 10 workplace Kirk 3 metres by3 I'd converted correctly.

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