Drill bit question

JAG

JAG

Well-Known Member
Hey Dogs! OK so after breaking 2 bits that I had today while trying to drill my handle pin holes in some O1 at 300 RPM, I need to buy some new bits. What kind of bits should I buy and do you guys use a chucked reamer after you drill? Do you countersink the holes as well so you don't have any issues during heat treating?
Any input you can give me would be appreciated!! Thanks!
 
buy the best bits you can afford. You get better holes and less frustration. There is a difference. For metal drilling, look for 135 degree split point. 118 degree bits are good for wood and other material. Jobber or short length bits break less. HSS bits are better than 'carbon' bits. Cobalt (usually M42) are better than HSS. Carbide bits are specialty bits for drilling already hardened material and should only be used for that.

It's odd to hear 2 bits got broken. Can you tell us how that happened and maybe we can help.
For better holes, generally, drill a few thousands smaller and ream to size.

I usually chamfer any dill holes for heat treat stress but I'm not so convinced it is needed.
 
o1 is hard to drill if ya don't anneal it after each forging,I use 3/16 carbide tipped bits at 1100 rpm to drill o1.
 
I tried to drill a small pilot hole first and it worked for the first hole then broke on the second hole. The second bit did the same thing. I think they are some Harbor Freight drills or something!! :eek:
 
By the way Boss, I bought that new knifemaker's vise last week from you and that thing is built like a tank!!
 
Jag get some cobalt bits in the sizes you use the most and only use them for anealled steel. I drill all my stainless with a split tip cobalt bit and I havent wore one out in 50 knives. dont drill a small hole then make it larger with a bigger bit your asking for trouble and will allways result in broken bits or handle material. If your drilling after heat treat CARBIDE is the only ones to get . kellyw
 
Thanks Kelly, I will get some Cobalt bits and will not drill a pilot hole. Thanks for the advice.
Do you just drill your holes or do you chamfer them as well? Jerry
 
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