Drilling hardened AEB-L

jdm61

jdm61

itinerant metal pounder
Joined
Aug 12, 2005
Messages
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I have some hardened AEB-L kitchen knife blades and I have decided that I want to put bolsters on one or two of them. What kind of drill bit or end mill should I use to drill 1/8 inch holes and what is the process for drilling them?
 
JDM61, About the only way to drill hardened steel is with Tungsten Carbide drills. You will probably break a couple in the process because they are brittle . I have a whole collection of them and my opinion on the best place to get them is this: Go online to Drill Bit City and look at the left side of their webpage and find the link to Drill Bit City II and there you will find reground Tungsten Carbide bits in fractional sizes and you can buy them in 5 packs. I have been using these for years. If you blade is too hard ( like Rockwell 62 or more) then you are out of luck I'm afraid. I have put bolsters on Damascus knife blades that I have purchased and I had to put heat sink paste and clamps and all the vise grip clamps I had for heat sinks and heat the tang area with a torch to soften enough for drilling. The heat might leave heat marks on your ricasso. Give it a try because you can always use the drills later. I hope this helps you. Larry

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I have several carbide bits I have purchased new from a jobber supply. The "FORD" brand have worked very well for me.
Frank
 
I use the carbide bits from usaknifemaker. Make sure you use a steel backer so it doesn't break when it comes through the back. I use them in a solid drill press and run 100-200 rpm. I use them on cpm154 at 61rc.
 
Another trick is to use a carbide ball endmill. If your drill press and chuck are in good solid condition and not wobbly then it should work like a charm. The issue with carbide drills is thy are brittle because thy are drill shape. The inlet time I ever found its worth using carbide drills was when drilling 500holes in a 316 stanless valve diffuser. Other then that I use 4flute ball endmills. Just peck at it and slowly make the hole. The flutes don't have much clearance on ball endmills that's why you peck at it. Take small bites and keep the chips cleaned out. Hell thats how I remove broken taps. I use ball endmills and drill the center of the tap out and use a dental pick to pick the teeth out of the threads. And that's HSS so I think thy should work just fine on Aeb-L
 
jdm61 said:
I have some hardened AEB-L kitchen knife blades and I have decided that I want to put bolsters on one or two of them. What kind of drill bit or end mill should I use to drill 1/8 inch holes and what is the process for drilling them?
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There can not be cheaper way than this , and safe too ..............67 Hrc HSS , take a minute to drill hole .

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PS. It s best to drill from both sides .When Drill bits make a small hole from one side , just continue from other side of handle .......
 
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i have drilled post heat treated tangs with a colbolt bit. However since I was using a forge at that time, the tang was probably not as hard as the blade.
 
You can get number, letter and fractional size carbide drills from MSC and ENCO. I would get a solid carbide straight flute and drill into a backer.
Carbide also likes to be run fast. An 1/8" bit I would not run between 600 and 1000 at minimum and peck.
 
be aware there are a few kinds of carbide drill bit

The most common is for soft abrasive materials like circuit boards and reinforced plastic. These won't work in hard steel, they break down.

There are carbide drills designed for hard materials. They're often a conventional drill design or a straight flute. They're expensive and have a narrow processing window.

There are concrete cutting masonry bits. They can be sharpened on a Blaze belt into something that cuts reasonably well.


Carbide works best in a rigid setup, so a mill or good drill press is helpful. Trying to do this with a hand held drill motor doesn't work great. <--- wear good eye protection

I use old ball endmills for stuff like this. They break down, but I keep old junk around just for this sort of thing. If you want some I'd be happy to send you a few.
 
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