Drilling out laser cut holes

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Apr 2, 2013
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If I was to have some blanks laser cut, but for the pin holes have a pilot hole cut instead of full size. How difficult would it be to expand these holes to the correct size? Assuming the holes would now be hardened by the laser cutting process.
 

Stacy E. Apelt - Bladesmith

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Just laser cut them oversize. Unless you are threading them, pin holes don't need to be exact. If you actually need precision holes, use a carbide drill bit followed by a carbide reamer.
 

Bill Siegle

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You can also have hole locations on blanks merely laser pierced and drill them out later. You’ll have a very tiny hole in an exact position that has not had enough heat exposure to harder the steel.
 

JTknives

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After laser cutting all parts from harden-able steel need to be fully annealed.

This is not true, I don’t know where you heard this.

Carbide will drill it out no problem. A little trick if the hole is just a tad on the small size then chuck up a carbide burr in your drill press and open up the hole. All the blades we cut here I center Mark with the cnc and then drill after. I use a carbide drill to spot drill the hard mark then drill to size with standard drill bit. Just remember to grind your profile a little bit to remove the HAZ. On the blanks we cut I usually recommend our customers remove .02 from the profile. The HAZ is less then that but better to much then to little.
 

JTknives

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You can also have hole locations on blanks merely laser pierced and drill them out later. You’ll have a very tiny hole in an exact position that has not had enough heat exposure to harder the steel.

The inside surface of the tiny hole will still be glass hard. We us to do this on the plasma and stopped and switched to just spot marking as it was easier to drill.
 

Daniel Fairly Knives

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I just cleaned up 225 laser cut blanks with one very used 120 belt, one drill bit and a few old chamfer bits. I'd try to drill them out with a decent cobalt bit.

Fiber laser... not many holes. Nitro-V air hardening steel.
 
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JT, you got NO wasted metal in that plate - almost full blades. Congrats on a well thought out process.
 

Daniel Fairly Knives

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225 as this one only has a lanyard hole. They were only a few thousandths under though so probably not too helpful here.
 
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225 as this one only has a lanyard hole. They were only a few thousandths under though so probably not too helpful here.
That is real interesting. Usually, the clean up passes are the worst because the nitriding/carbiding is so thin and only the corner of the drill makes contact. That can be mitigated by gas mix and dialing in the set up. Sounds like you got a good laser outfit.
 

kuraki

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My standard practice is to laser cut .007" undersize and ream to finished size after heat treat with a carbide reamer.
 

Daniel Fairly Knives

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My standard practice is to laser cut .007" undersize and ream to finished size after heat treat with a carbide reamer.

I do the same prior to heat treat with my waterjet cut framelocks. How many blades are you getting per reamer? Sounds good after ht/double disc grinding.
 
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This is not true, I don’t know where you heard this.

Carbide will drill it out no problem. A little trick if the hole is just a tad on the small size then chuck up a carbide burr in your drill press and open up the hole. All the blades we cut here I center Mark with the cnc and then drill after. I use a carbide drill to spot drill the hard mark then drill to size with standard drill bit. Just remember to grind your profile a little bit to remove the HAZ. On the blanks we cut I usually recommend our customers remove .02 from the profile. The HAZ is less then that but better to much then to little.

I didn't hear it, it's based on my 20 years of experience making and selling knives. But hey, you're the expert, go ahead dulling your expensive carbide drill bits.
 
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