Hunters, fishermen, backpackers, hikers, ranchers, carry small sheath knives around our small town all the time without LEO's saying anything. You call the DA or ask a cop and they will say absolutely not because they don't want to be liable if you do something stupid. So why do you want to carry a fixed blade instead of an ordinary folder? It is against the law to carry any size of knife as a weapon here but there are no restriction on knives that are required as tools. The critical point being will you have a real reason to need it as a tool if they ask.
"I trust it more" or "I think it requires less maintenance" or just "I like fixed blades" is actually all the reason you need so long as you follow that part about it being a tool. A cop isn't going to see you in the grocery store and just start giving you a hard time over it. Get in a fight at a bar with it on you, that would probably be a different story.
As far as the length limit goes, it is incorrect to say there isn't one. What the actual problem is, some counties defer to the statutory law ( which doesn't define a length
, while others have their own length restrictions. Counties on the West side of the Cascades especially. Try to Google around some more, I once found a list of all the county length limits, but I'm on my smartphone now so can't search right at the moment.
The other thing is that say you actually have a cop made at you because you've been bad, and he has found your knife. In this state it's more common for them to check the length against the palm of their hand. If it's longer than their palm is wide it's a "dangerous weapon". However, the good news is that, you've got to already be doing something wrong for a cop to be searching you and considering it a "dangerous weapon" rather than a tool. No cop is just gonna stop you on the street or even if they're writing you a simple ticket and ask to see it and check the length, if they even see it at all.
I've had more than my fair share of tickets... Not once has a cop ever asked me if I had a weapon on me. If they had I would always say "Nope just my knife." So unless you're often stopped, asked to leave your vehicle and terry searched, I really wouldn't worry too much.
Plus, as Sidehill said, it's really not unusual to see guys with fixed blades on them. I think though that over in Seattle and that kind of metropolitan area it would be a bit less of the norm.