Looking for someone to drill through hardened steel

G

guitardemon

Joined
Jun 8, 2005
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Im looking for someone to drill a couple holes in my knife. I have a fallkniven f1 knife blank that I am having trouble with. It has 15/64" holes in the handle and I'm trying to put some 1/4" holes in for pins. I was told that cobalt bits could drill through hardened steel but all I seem to do is ruin the bit (I drilled slow, tried not to heat the bit, and used oil). Is there anyone who has a setup that can drill through this, that I can send my knife to? I am willing to pay for shipping, and any reasonable charge to drill the knife.
 
You could try getting a carbide masonry bit at a lumber yard or hardware store. The hole will not be precision 1/4". It will be a little over size.

I've used them to drill hard spots in tangs but have never used one to make an existing hole a little bigger.

Mike
 
I know it is not what you asked, but have you considered getting the pins turned down to 15/64 on a lathe?
 
Just go to your local hardware store and buy a tungsten carbide drill bit (they have bits meant for steel). It will drill through the hardened steel just fine. Just use plenty of water or oil for coolant. No need to ship your knife to have the holes drilled. Plus you get to keep the bit! ;)
 
Make sure that blade is clamped down good! When enlarging holes, the bit tends to grab. Then you have a sharp propeller spinning, good way to lose a finger or two.

John
 
Do you have a dremel tool or an end grinder. If so get a small carbide bur (rotary file) and use that. They have a million uses and will cut hardened steel. You can even do "file" work on the spine of a hardened blade with them. If you got one a 1/4" od you could use it to "drill" the holes out to 1/4" and after your done have a versatile tool. I like the ones shaped like a rounded cone best. Jim
 
As always I'm abit confused. Are you simply drilling out the existing holes or are you drilling new holes?
 
I'd say to drill a blade with a 64 Rockwell hardness core like that one that you want to spend the money to get carbides at MSC in two flute style drills. Personally I'd drill a 1/8" hole first and then follow in after it with the 1/4" drill. The bigger the drill the more heat it produces and even if you take it slow its going to cause enough friction to possibly burn mark if you are not experienced doing it. Also, the bigger drills tend to fracture on the exit a lot easier along the edges when someone not familar with carbides uses one for the first time because they are hard but so much so they are brittle so its best to clamp the blade down on another hard surface under it to keep that from happening best you can when the drill exits the other side of the blade. My brother came here once and grabbed up a big expensive carbide thinking he would make life easier for himself not knowing their characteristic behaviors. He shattered a brand new bit that was not cheap because he had it clamped down but on a soft piece of wood. Didn't work. I was not happy with that.
STR
 
I think I cut on one of those for Mete a while back

mete3.jpg


That core is some tough stuff. I'm confident that cobalt HSS won't cut it.

You're enlarging a existing hole. So a $4.00 four flute carbide endmill can plunge that part if it is rigidly clamped down.

While Carter is correct that carbide does well with speed, it does not tolerate chatter, which can be complicated by speed. I would spin a 1/4" bit at about 700 RPM for this if you do it in a good rigid setup. For this operation it won't make any difference if you use coolant or oil or not, so I wouldn't bother.

I wouldn't attempt it without a good rigid setup except perhaps with a carbide tip concrete bit.
 
Bruce Bump said:
As always I'm abit confused. Are you simply drilling out the existing holes or are you drilling new holes?
Click to expand...

Ya, I thought he just wanted to take the holes that are there and make them 1/64 larger. A carbide bur would do that easy. If he wants a new hole I agree the way to go is a carbide drill, but he needs a drill press or a milling machine to do it with a carbide bit.
 
I use to know an old machinist, he is dead now and I have always regretted not picking his brain a little more. I had a project going that I had used old bed rails to weld up and the heating of the welding had tempered the angle iron or something. I had to drill over a hundred 1/4" holes and I was burning up bits about every third of fourth hole. I asked him if he had a bit that would cut this steel as I had over a hundred holes still to drill.
He asked me how I had been running the bit and I told him trying to run at a moderate speed without too much pressure, you know let the bit cut and try not to overheat it!
He walked over to a box of bits he had sleceted a bit the right size and by eye throws it on the grinder and touches up the edge. I think what he did was he change the angle of the bit. I would have to look it up again buth angle of the point is different for steel that say for concrete. He also told me to run this bit as fast as I could with as much pressure as I could.
I cut those 100+ holes I had to cut without failure. Oh I forgot to mention this was nothing but a regular concrete bit with a carbide tip, and I am pretty sure all the ole man done was changed the angle on the carbide point and the bit never failed.
When I was done I took it back to him and he said , "Oh you could have kept that, it wasn't nothing special"! It was too me I have never seen a bit cut like that one before or since and especially given the fact it was just old masonary bit!
 
Dixieblade57 said:
I use to know an old machinist, he is dead now and I have always regretted not picking his brain a little more. I had a project going that I had used old bed rails to weld up and the heating of the welding had tempered the angle iron or something. I had to drill over a hundred 1/4" holes and I was burning up bits about every third of fourth hole. I asked him if he had a bit that would cut this steel as I had over a hundred holes still to drill.
He asked me how I had been running the bit and I told him trying to run at a moderate speed without too much pressure, you know let the bit cut and try not to overheat it!
He walked over to a box of bits he had sleceted a bit the right size and by eye throws it on the grinder and touches up the edge. I think what he did was he change the angle of the bit. I would have to look it up again buth angle of the point is different for steel that say for concrete. He also told me to run this bit as fast as I could with as much pressure as I could.
I cut those 100+ holes I had to cut without failure. Oh I forgot to mention this was nothing but a regular concrete bit with a carbide tip, and I am pretty sure all the ole man done was changed the angle on the carbide point and the bit never failed.
When I was done I took it back to him and he said , "Oh you could have kept that, it wasn't nothing special"! It was too me I have never seen a bit cut like that one before or since and especially given the fact it was just old masonary bit!
Click to expand...



Good story.
I think what he did was use a standard masonry bit and put cutting sharp edges on it with a carbide grinding wheel. A store bought masonary bit isnt very sharp. Most of us cant grind carbide because it requires a diamond stone and a very solid rest. I have my carbide tools modified at times by a machinist friend with a tool post grinder.
 
I drilled through hard 1095 with a masonry bit with no problem when all other bits just squealed and dulled instantly. I did not even sharpen the bit or anything. They work great when nothing else does. A bit crude perhaps, but gets the job done.
 
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