I've never used a zip tie. I found some old pics that I took to help a friend out, that had the same problem as you. Maybe these pics will help you out as well. It was when I was doing a Boomer52 scale swap on a HAP40 Endura.
Depressing the lockbar, push the pivot pin out. Pull blade and washers out.
Totally disassembled. Here's where I'll wipe everything real good with a microfiber cloth. Drop of oil on moving parts and washers.
Assemble everything back together as you see below, except for the lockbar barrel, I forgot to remove it in this pic.
This is where I adjust blade tension and center the blade up. When the blade is centered up, tighten all handle screws and loctite your pivot.
Now everything is re-assembled except for the lockbar itself and the lockbar barrel. The spring is in, but you can't see it.
Put the lockbar back in and push the barrel in, it will touch the lockbar and will not go in any further.
Turn it over as seen below and push the lockbar in with both thumbs and at the same time, push the barrel nut against something from the bottom. Use your thumbs to shift the lockbar left or right a little bit to line up the holes. Once the hole lines up, the barrel will push right through. This will eliminate the need for a zip tie.
Done! Easy peasy!
I always loctite this lockbar screw. Don't over-tighten as it may affect the action of the knife.
Centered and solid with no blade play!
Hope this helps!