Doing the countersink/bore is definitely easier with a thicker liner and a good idea
. I made my first folder with teflon washers and no counterbore on the blade or liners, just a real tight fitting pivot bolt (.0005 clearance). A lot of hand fitting too, but beware if you open it up as you don't want all those little bearings going all over.LOL I would definitely use the sealed bearings and maybe will on the next folder I decide to make versus the teflon/bronze washers.