Drilling

E

Ellis483

Joined
Jun 16, 2019
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I am retired and just learning, I have some CPM 3v that I have shaped and filed the initial bevels. I have been trying to drill holes in the handle with little luck.
I have tried a number of different bits including a carbide bit without any luck. The bill it’s are straight from Alpha Knife Supply and have not been heat treated.
I have tried my drill press , hand drill , fast and slow with plenty of oil.
HELP
 
In unhardened state? Typically feed pressure. You need to get under the chatter. Drill press is best for rigidity.
 
If it's soft enough to file, drilling shouldn't be a problem. You need to mark your hole location with a punch, clamp it securely and use a drill press. Don't risk breaking your carbide bits, get some 10 pack of cobalt bits from Amazon, preferably M42.
 
Richard338 said:
If it's soft enough to file, drilling shouldn't be a problem. You need to mark your hole location with a punch, clamp it securely and use a drill press. Don't risk breaking your carbide bits, get some 10 pack of cobalt bits from Amazon, preferably M42.
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Thank you both for the advice, I ordered the recommended carbide bits. I have seen conflicting advice on the drilling speed of the drill press, what is the correct call on speed.’ Also, there is not a local heat treating company close that will do small batches. are the places like Texas Knife Makers Supply reliable or any other sugestions. Thank you i really appreciate the help
 
What size twist drill are you using?

Some quick math based on .188" drill diameter and 40 SFM (close to what ive used for drilling D2. CPM shows its typical for 241 BHN in its annealed state)
(3.8197 / Drill Diameter) x S.F.M.
(3.8197)/0.188x40 = 812 RPM

Or if its harder than 250 BHN drop the SFM down to 30 and you get 610 RPM.

Feed rate of say ohhh... around .003-.004" per rev. Feed pressure is key to keep it from vibrating.

edit again: Make sure you centre drill your holes. For drilling I like to use rapid tap or a similar product.
 
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Use lube/coolant. I use liquid dish soap for a hole or two
 
There are speed charts that depend on the material and size of the bit. I just leave mine on one of the slower speeds as it's a bit of a pain to change the belts around.
For heat treatment, Peters is a big commercial place in PA. They've done a lot of 3V for me. Not the cheapest for small batches, but that's where I send mine.
 
Jarod Todd can heat treat single blades. I use Bos Heat Treating at Buck Knives, but for larger batches. Peters is good, not sure what they charge for a single blade though? Some of the guys here may be able to do it for you? Where are you located?

Texas Knife Supply only tempers to 58 rockwell and the cryo is done the next day (according to their website), so it may not be as beneficial. I tried to get TKS to do some steels to 60 HRC and they said they wouldn't.
 
See if you can find the spade type bits for glass and stone (not the wood spade bits!!). I've used those to open up holes even in hardened steel in the drill press.
 
Ensure there is no garnet stuck in the hole from the water jet - there shouldn't be, but that stuff will end a twist drill's life in a heart beat.
 
A step drill is pretty forgiving going through thin stock, opening up holes.

Your pilot holes are probably big for your 3/8" drill, are you getting chatter?

On my 3V blades I put .320" holes in with no problem in a drill press .


The Only holes I have trouble with is when I'm drilling power hacksaw blades. Hardened at 64-66HRC. Ugh!
 
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3/8" diameter is a heck of a hole. I wonder if you're not work hardening before the bit breaks through. Are you drilling pilot holes? I'd say use a drill press, but your average drill press will likely still be pushing the speed limit even at the lowest setting. A pilot hole will help though.

I recently drilled 100's of 1/8" holes into some .070 CPM3V with the same HSS drill bit without a single issue. Minimal cutting oil was used, but I did use some Moly-D.

What type of cutting oil are you using? If you want a good, cheap cutting oil, get a gallon of Sulphur based cutting oil from your nearest big box store's plumbing section. It's normally used for threading pipe. It's about $25 for a gallon and will probably last you the rest of your life.
 
Natlek said:
What kind of drill bits you use for drilling in power hacksaw blades ?
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I use the cheapo carbide tipped ones from ebay. Twist and sharpened for metal, will do 5-10 holes before they are pepsi. I will not bother with sharpening masonry bits or buying expensive carbide any more, since these are like 1 euro a piece.
 
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