drill bit question

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fatalhubris

Joined
Dec 30, 2006
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I am trying to drill pinholes in a knife I was given. But I keep breaking bits.
I'm just guessing but do need to I or should I try heating up the handle to soften the steal? Or is it just cheep bits? Are there any specific mettle cutting bits I should be using? If so where is a good place to lay my hands on some? Any advice is welcome at this point.
 
there are bits ment to cut in to metal...if u use a wood bit they will do nothign nothing then go BINK and break..... there are also concret bit...they will probly not break but have NO way of drilling into steel... so go to ur local hardwear store fine the Bits section and look around or ask some one for steel bits...they are there trust me i use them alot...and rember u get what u pay for i recomend that u get a kit with 5 bits or so....and then when drilling start off slow then speed up when u are in the correct position....apply presure but not TOO much....sry but it is kinda hard to do it right sometime... but im sure ur smart enough to figure it out u have to be u like knives!!!
 
They keep breaking b/c the steel is harder than the typical steel used in the bit... try and find a Cobalt-Steel or even better, a Titanium-Nitride (golden coating) bit... OR even better than any coating, a nice solid Tungsten Carbide bit - which will bore through any metal matrix like butter... Just becareful with T-Carbide bits, b/c they will chip if too much shock is applied.
 
Fatal, what ,exactly, are you trying to drill ? An older already completed knife ? Pre- ground hardened Blade that you plan on finishing ? Edit to add and what are you using to drill with, drill press, hand drill ?
 
You need to purchase good quality bits. And when you are drilling through the steel may sure you drill slow and use a cooling solution. It sounds like you are drilling without any cooling solution and maybe pushing to hard on the bits creating heat that will destroy the cutting edge from bit. Hope this was of help to you. God bless and have a great knife day in the shop.

Barkes :thumbup:
When I leave this world I would like to be known by the one who make his knives from start to finish.
http://my.hsonline.net/wizard/knifeshop.htm
1.812.526.6390
 
I used to break drill bits all the time...I have a wide collection of bit of busted drill bits all over my shop.

Then I got the video by Wally Hayes and he talked about COLBOLT drill bits.
I got some and tried them out.

They are not magic,,,,,but they are a lot better than the other bits I used before.

if you can use a drill press you are better off, and cutting oil is a lot of help too,
Holding the steel so that it cant move at all really helps, as is steel that you might be able to ANNEAL

One more thing...dont use a drill press with gloves on...(Even in the winter)..or are gloves that have fingers,,,,
I alomst lost a finger when the bit snagged a loose torn section of a glove and dragged me into the spinning bit.
 
A tip I read the other day might help here. A guy was trying to drill holes in some hacksaw blades and someone suggested cutting the point off a nail and setting the nail in the drill press to "drill" at the spot where the hole was to be. With a little pressure on the sacrificial nail/drill the steel beneath heats up enough to anneal it but only in a very localised area.
Switch to the correct drill bit once the spot is annealed then repeat the process for any other holes.

Seems to make sense to me.
 
longstrider, have you actually tried this? I tried it awhile ago on some metal that didnt seem to be fully annealed, it pretty much did nothing except polish the nail b/c the steel was so much harder, the polishing took away what little friction there was, the way I tried it was to go through the speeds on my drill press from slowest to fastest, and then even tried my dremel at 35,000 rpm and the steel might have been slightly warmer than when i started, but definitely not enough to effect the temper....just my experience
 
Nope. :o Never found a piece of steel my cobalts wouldn't drill. I was just trying to save the guy the trouble and expense of getting cobalt bits if he didn't need to. Like I said, it was a tip I saw on another forum and I thought it made some sense. Air hardening steels would probably only spot harden I guess. I hadn't thought of that problem. :o
 
yes,you can use carbide tipped concrete bits to drill hardened steel.i am a toolmaker,and we do this stuff all the time.what you have to do is regrind the angle of the cutting edge.grind it at a lot steeper angle than they come from the package,use coolant constantly ,and run at about 400-600rpm.practice makes perfect.be careful when breaking thru though,that is when most of them break and don't be afraid to resharpen it when it dulls.but if they chip badly,and they will,you are better off throwing them away and getting another.and yes titanium coated bits cut alot longer before needing resharpening
 
Sorry devils in the details Dave.

It’s a pre ground blade from the looks of things nearly finished just no handle or holes to pin it. It was given to me by a guy at work who does mettle detecting as a hobby. So I have no idea as to what has been done to it heat treating wise. I'm using a friend’s drill press.I was using one of the Titanium-Nitride bits some one suggested. that's what got me to wondering if it was to hard to drill. or if the bits were the wrong kind to be using for this sort of thing.
 
baliblaster said:
yes,you can use carbide tipped concrete bits to drill hardened steel.i am a toolmaker,and we do this stuff all the time.what you have to do is regrind the angle of the cutting edge.grind it at a lot steeper angle than they come from the package,use coolant constantly ,and run at about 400-600rpm.practice makes perfect.be careful when breaking thru though,that is when most of them break and don't be afraid to resharpen it when it dulls.but if they chip badly,and they will,you are better off throwing them away and getting another.and yes titanium coated bits cut alot longer before needing resharpening
Click to expand...
I have run into this idea of the use of concrete drill bits to drill in hard steel before.

But as for the 400-600 rpm?...I need to to take a guess here.

I own the normal type drill press sold at a place like Ace, or Lowles,,,and it has a belt that you can put on different sections of the drive wheels to change the speeds.

But I dont have a clue what RPM is being used at any one setting.

Cou you gess and tell me if the correct speed for the use of a concret bit, is it fast?, very slow?, 1/2 way??, or 1/2 fast. or 1/2 way slow?...so I could then guess the placement of the belt on the wheels?
 
Alan,

I shouldn't say typically, But typically, a "standard" multi-speed drill press will run at a low of 300-600 rpm and up to a high of 3000 rpm or more, so baliblaster is suggesting the low end of available rpm.
The original question was what drill bit....for pin holes. if the ins are pretty good diameter, the concrete bit might well work.
If the holes are smaller, you may need to go with solid csrbide or at least carbide tipped bit. They are available from places like www.msc-direct.com
but are not inexpensive and if solid carbide, brittle (carbide runs in the 90-95 Rc in hardness....a higher end Rc for heat treated blade steel is in 58-64 range-ish). so it is pretty easy to break a carbide bit....and that can hurt your "billfold"....but it is worth the risk to achieve the results without annealling the already hardened knife steel.
 
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