Is there some sort of trick to keying a canvas?

First time working with a canvas big enough to need keys.  As I understand, they help tighten the canvas, which would be extremely helpful!   It's tight, but sensitive to humidity changes.

The keys keep falling out.

Is there some sort of trick to this?


https://en.wikipedia.org/wiki/Tightening_key

Ah ha!

I put mine in the wrong way, with the slant pointing away from the corrner.



I'm morning how many hours of my life (3) I lost to this problem.

Nope, that way of putting the keys in was just as bad.  They all fall out!

jacksons suggests we can use keys either way

Here is my theory

1. The staples they used over the join to attach the canvas is preventing it from stretching

2. The glue they used to neaten down the corrners of the canvas is preventing it from stretching

Or

3. The keys are too smooth.

One and two seem hard to fix.  So I focused on 3 and appled some hide glue (because easily reversable) to one side of each key and will leave it to dry.  This isn't to glue the key in place.  Instead, this liquid hide glue seems to stay slightly tacky for about 4 days and might provide enough friction when I insert them tomorrow.

Didn't work. Keys are too thin.

New theory.  Keys are too small or wrong shape.

User error is still on the table