Dang blast it...

Kalindras

Kalindras

Joined
Aug 24, 1999
Messages
933
Okay, guys...need opinions.

I recently came into a few blades that a buddy had lying around. Great! No! They're full tang, but have no holes drilled in them for pins! Rats!

So, I throw them on the trusty drill press, and figure, "Well, heck, I'll just punch some m'self, right?"

WRONG! Of COURSE, he hadn't mentioned that they'd already been hardened...so I just chewed up a couple of bits... *sigh*.

Now, here's the total picture: 3 blades, hardened to an unknown Rockwell, of unknown steel (he made them about four years back), ranging from 1/8" to 1/4" (he was fooling around making different sizes and weights).

I've burned up a carbon bit, a "Zirconium Nitride" bit, and a HSS bit--and barely even scratched them. Since I don't have any info on what they are to re-treat them, I would prefer not to have to anneal them to drill them out. While laser cutting is not an option, I'm willing to put up some decent bucks for bits, as long as I know they'll do the job. I was looking at Titanium Nitride bits for it, but I was hoping I could get some input before I shelled out the $$ for them, just to have them burn up, too.

Thoughts? I know a bunch of you guys are masters of metallurgy, out there. I beg your advice! Thanks in advance!

confused.gif



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Meddle not in the affairs of Dragons, for you are crunchy, and good with ketchup...
 
What I would do is take a propane torch and anneal the spots you are trying to drill.Another way is take a 16penny nail,cut the head off and chuck it up in the drill press .You will anneal just the spot you want by running it at high speed on the spots.I have used both methods. Robert
 
Either spot anneal after wrapping the blade in thick wet felt or grab a couple of glass drilling bits. Use them at the slowest speed possible and don't apply any pressure. If you go really slow this will work. We just went through this proccess a week ago.
smile.gif


Good Luck!

Dave Evans
Tenino, WA

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Proud Member
Buck Collector's Club
American Knife and Tool Institute
Oregon Knife Collectors Association
UsedKnife.Com
 
I have used carbide bits as Tom Mayo recommended. Works like a champ but you MUST use a drill press. Carbide bits are very brittle and if you get the least bit off center in the hole and you end up with a broken bit. The PC board type carbide bits seem to work OK for most applications.

Craig
 
I think I've tried the titanium nitritde bits your talking about before. You mean the ones with a yellow plating on them thats titanium something or other right? They all have some kind of add on them that says they last up to six times longer than high speed steel bits? If those are the ones, there not worth trying. All my experience with them is they cut hardened steel like butter as long as their sharp, and they stay sharp almost long enough to get a good start on the hole. They bite right in and don't walk on you, but you don't get much farther than the tip of the bit before the coating has worn off, and it doesn't cut for sh*t, not even in soft wood.

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It'll feel better when it stops hurting.
 
I had to drill some hardened l-6 the other day. Use the carbide bit and spray a little oil in the drill hole while drilling.

take care
TJ Smith
 
The easiest way to "spot temper" in my experience is to get a large, straight nail (16 penny) and cut the head and point off square (it's important that it contact the tang squarely to it till generate uniform heat in the area you want to soften). Chuck it up in your drill press and clamp the blade to your press table. Start the press and lower the "tempering bit" (ie nail) to the spot where you want the hole to be. Hold the nail in place until the spot on the tang heats up enough to turn dark blue then use a good HSS drill to drill the hole. Usuallym depending on the steel, this softens the tangs enough to drill a hole with a "normal" bit.

The last time I suggested this trick, a guy complained that he tried it on O-1 and could not get it to work. Upon further inquiry, it came out that he used a healthy dose of Cool-Tool on his "tempering bit" resulting in reduced friction and consequently reduced heat...defeating the purpose. So suffice it to say...don't do that
smile.gif


Take care, hope it helps,
Cecil

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Cecil Self
SELF Knives
Arrow-Dynamics Cutting Tools
www.arrow-dynamics.com
 
The 16penny nail trick will work. I tried just a few minutes ago.
Be sure it gets REALLY hot in the spot you need annealed.

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Timing
If you want to be seen, know when to stand up.
If you want to be heard, know when to speak up.
If you want to be appreciated, know when to shut up.
 
Thanks, guys!

I'll try spot annealing it, before I go out and shuck some more money for bits.

BTW, just as a safety precaution, I noticed a couple of you mentioned heat-sinking the blade...is there anything specific (I saw wet felt mentioned and didn't know if this was a specific need, or just a personal tip), or can I use some of my heatshield paste?

Thanks again, folks, you've probably saved my blades, and I know you've saved my sanity!!



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Meddle not in the affairs of Dragons, for you are crunchy, and good with ketchup...
 
Just a quick update on this one...

WinDancer--

Is it possible to send a big, sloppy kiss via email??? That glass drilling bit thing is da BOMB!

Even without spot annealing, I was able to punch through hardened steel like BUTTER! The only caveat is to make sure you don't skimp on the cutting fluid...or else you'll get about three holes out of your bit, and then it will, quite literally, disintegrate.

Thanks again to everyone who helped me out on this one! Once I get these blades finished up, I'll try to get the digicam working and post some pics!


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Meddle not in the affairs of Dragons, for you are crunchy, and good with ketchup...
 
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