I have a Peter Lynn Suspension Buggy with custom 2-piece rims that a previous owner installed. I am systematically replacing all the bearings, nuts and bolts on the buggy. Especially the rear axle since they are NOT SS.

My understanding is that the PL axle is 15mm. Looking at the bearings on the 2-piece rims they show 6202-2RS.

I bought 6202-2RS bearings which have the dimensions: 35mm OD, 15mm ID, 11mm width. When I tried to put the existing axle bolt through this bearing, the threads would barely fit and the shoulder (i.e. part without threads) would not fit.

I went back to the original bearings and saw that "6202-2RS 5/8". I missed the 5/8" portion. So, maybe they are 5/8" (a 5/8" bolt DOES fit through the original bearings). I have now bought bearings which have the dimensions: 35mm OD, 15.875mm (0.625") ID, and 11mm width. They arrive in a week.

I brought the mystery bolt to ACE hardware to try to find a mate. I tried 5/8-11 and 5/8-18 nuts and neither matched. A 16-1.5mm and 16-2.0mm nut was tried and one would not thread far and the other was loose when installed (I cannot remember which was which)

Q1: If this is a 15mm bolt, why would a 16mm nut fit on it? This leads me to think it is SAE.
Q2: If this is SAE and neither a 5/8-11 or 5/8-18 will fit, what could it be? McMaster does not list anything but 5/8-11 or 5/8-18.
Q3: why is 15mm NOT listed in McMaster Carr as a bolt size?
Q4: Do you have ideas on how I can determine the size of this bolt?


If you have a 15mm bolt can you take a few measurements? ID at threads, ID at shoulder, Thread-pitch (count the # threads per inch or per 10 mm) is what I would need to at least rule OUT this possibility.

Thanks!
Paul