On Thursday, September 24, 2020 at 11:20:48 AM UTC-4, Andrew M wrote:
On Thursday, September 24, 2020 at 6:47:03 AM UTC-7, dpb wrote:
On 9/24/2020 8:00 AM, Leon wrote:
...
Yes most circular saws have arbor locks.
I've yet to see one... ???

A flat maybe, a lock is pretty rare.

--
So an update--the sanding solution worked initially, however once I swapped back to the dado stack and then tried to reinstall the single blade, I had the slippage occur again...Frustrating.

Fortunately, the thin wrench set I ordered from amazon arrived and I was able to use the 7/8" thin wrench on the arbor which held the arbor in place while I tightened the 1-1/16" arbor nut.
This is what I ordered: https://www.amazon.com/Grip-Super-Th.../dp/B001HZQW0Y
Can you tighten the nut with no blade installed? Have you tried adding an additional or thicker washer and then tightening?