You searched and couldn't find the answer??????
I posted the answer before the question was ever asked, when you bought these Konis in the classifieds!!!!
Koni Boge Strut Housing Collar Spacer Gland Nut
Note from my above post that the original Boge collar/gland nuts are recommended over the Bilstein nuts, if it so happens that your Boges have been refreshed with Bilstein inserts at some point.
Seems like Koni customer service is about as useless as their instructions (no words, only hard to comprehend pictures) so contact Paragon Products (jason "at" ***************** "dot" com). Jason Burkett is the Koni expert and he'll get you some of the centering rings. Here's some information I got from him when I was questioning the use of the rings and the top collar/gland nuts. My questions are in regular text and the bold italic are the responses
My front Konis did not come with a gland/collar/spanner nut in the box. The instructions show an internal spanner nut. Even if I did have the internal nut it would not work since my strut tubes have external threads. Sorry if I should have specified external threaded Boge when ordering- I didn't know the Boges varied in thread type. Should I use the original Boge nut or do I need a special nut from you?
The external threaded strut is from a Carrera (84-89) and the intent is that you reuse the nut that's on the strut and use the thick washer Koni supplies. The washer centers the insert and then the female gland nut screw on and holds everything in place.
Unfortunately I don't have the original Boge nut because I replaced the shocks with Bilsteins after buying the car in 2000. I'm sure I could dig one up. It looks like the Bilstein nut may work if I use the 10mm steel ring that was included with the Konis.
That's possible...I'd have to see what you have.
Is that what the 10mm ring is for, to be used under the spanner nut?
Correct.
That's how it appears to me from the Koni instructions. But i'm still unsure since I found other people concerned with the Koni-in-Boge nut not threading all the way down- see attached picture.
That's typical...it can't go all the way down cause it's both centering the insert and holding it in place...if it threaded all the way down the insert would likely be loose in the tube.