@Glenacius_K , I’m about to epoxy my maple KNack back together. It came apart after lots and lots of play. I’m planning on using 8 playing cards for the gap, like you’ve recommended.
For the response holes, do you recommend lining up the holes or offsetting them?
Would either orientation affect play in any noticeable way?
Sorry it came apart mate, but it can happen. Usually only the ones with wood glue instead of epoxy.
An 8 card gap is fine. I use red cup bicycle cards.
No need to line up the response holes, but line up the grain in both halves.
One more question:
Should I apply epoxy to just the end of the axle or a bit on the sides as well?
I figure I get one shot at this, so I want to get it right 
Just a thought from an old guy.
Epoxy is very good but it is PERMANENT.
I have repaired some old wooden yoyos. I have had good success with Elmer’s white glue (or equivalent). It is pretty much permanent but NOT to the paint where it is destructive if you ever need to do maintenance again.
YMMV
If I went the non-epoxy route, is there any reason for a white glue over a wood glue?
In my experience the white glue holds better and longer. I was using wood glues first without success, like they would dry out with only a few weeks of play. I’ve had to repair several vintage 3 piece designs as the old glue had dried out so much and they became brittle. I live in a dry climate, so it may depend on your local environment.
This Trickster needed a glue job.
I’m in Kansas, so a lot of weather variation. That’s part of why I’m leaning toward epoxy due to frequent humidity and temperature changes from week to week. But maybe I’ll try white glue first and see how that goes.
White glue is a wood glue.
Unless you SOAK the joint in water it will stay intact. Humidity changes would not be sufficient to compromise the joint.
I recently lived in Manhattan, KS for seven years. High humidity was never an issue, usually the opposite. I ran multiple humidifiers at h ome and in the office as well as both music stores.
Houston is another story. My white glued yoyos have no problem with the joints and we are usually melting here…
