Micromark test roller question

My 2 sets came as pictured.

@jini5 posted:

I have recently bought a new set of rollers from Micromark. After reading previous posts on these test rollers, I was under the impression that the buyer had to install 6-32 nuts on the bottom of the rollers to get them to sit between the rails to avoid wobbling. However mine showed up with brass circular nuts that lock the roller between the rails. I am wondering if this is a new style or possibly a different set offered by Micromark. Has anyone else received the set with the brass nuts. I am considering another set, These seem to lock in between the rails nicely (at least on Atlas track) Not sure how they will do on Gargraves. Heres a few pics

Mine too. I use marx track on my workbench. Fit perfectly, nice and tight.

I received a set last month as well, same as yours. I noticed that they fit snug on O Gauge, but are "loose" on O27. Since the rail bore is different, I assume that is the reason.

If yours fit well on the track you are using, then no need to do anything. But if you experience some wobble, by all means retrofit with the nuts.

Maybe my crest rollers need those round nuts. Locomotives wobble on the crest rollers i have even tho I've added nut's.  If Micro Marks rollers don't wobble please let me know.

I just received my set of Micro Marks as well. I had 6/32 nuts to put on the bottom but mine had the brass looking collars as well. They still wobble a little on a test track with Gargraves but no movement at all when in operation with the weight of a locomotive. The collars will come off if you want to replace them with nuts. I was going to but felt no need to after using them as they worked perfectly with the collars. Laidoffsick did a YouTube video on these and mentioned the use of nuts but I think at the time of the video 4+ years ago Micro Mark rollers did not have these collars. They probably took a note from his video and added these.

Brad