I make a lot of non folder knife handles, but I cannot carry them in WA state.
What do you mean you cant carry them?
From:
https://knifeup.com/washington-knife-laws/Conclusion on Washington State Knife Laws
It is illegal to own a switchblade or other spring blade knife in the state of Washington.
It is illegal to conceal carry a dirk, dagger, or other dangerous weapon. It is legal to open carry any type of weapon, so long as it is not carried in a way that may cause others alarm.
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Bruce