Loose tuning keys

[Swills]

Here’s a thing. I’ve changed the tuning keys on my Bass Centre Detroit and the holes drilled for the generic tuning keys are bigger than the replacements. 
 

I’ve measured and made sure I’ve got the same sized replacements, which are 1/2, however they are noticeably loose in the headstock hole.
 

I’ve noted that there isn’t a counterbore but I expected the sleeve and nut to be nice and snug.
 

Has anyone any advice for making the fit a little tighter? 

[Doctor J]

Get some aluminium tape from screwfix and run a thin strip around the bit of the ferrule which isn't quite snug enough.

[WubWub]

It doesn't even have to be aluminium tape, literally anything that is the correct thickness, even paper. The backplate and nut of the tuner will stop it falling out. 

[Swills]

Bosh!