All of the Magic Pie axle threads I've seen have been M14 x 1.5mm, but M14 threads are available with several different pitches including 1.0mm, 1.25mm, 1.5mm and 2.0mm.
I suggest you check out
this post and then measure the exact pitch of your axle's thread to ensure you purchase the correct threaded nuts.
A thread pitch gauge is the easiest and most accurate way to confirm the exact pitch of a thread:
![](http://www.icscuttingtools.com/imagesMX/products/screw-pitch-guage-001.jpg)
![](http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/0c/29/e8/medium/0900c152800c29e8.gif)
But not many people have access to one of these.
![Sad :(](https://goldenmotor.com/SMF/Smileys/default/sad.gif)
Measuring the distance over ten threads
(between 11 crests) should be accurate enough as shown here:
![](http://goldenmotor.com/SMF/index.php?action=dlattach;topic=3266.0;attach=4646;image)
If yours is 15mm it will be a 1.5mm pitch, in which case these
M14 x 1.5 Nyloc nuts on eBay should fit.
But if yours only measures 12.5mm across ten threads it will be a 1.25mm pitch.
Alan