Tonearm recommendation

No, not what I meant at all. I am well aware of the VTF/VTA interaction you describe and appreciate the need to adjust the two iteratively. First time I observed this was on my old TriPlanar and the effect was not subtle (from recollection 0.5G or more going from my initial VTA/SRA setting to where I finally settled)

What I am referring to is that the small counterweight on the Kairos is rather loosely threaded and thus with gross movement of the arm (i.e. moving it on and off records) it may wander slightly. I've never seen this happen but have merely observed that when I recheck VTF it has sometimes shifted despite my having made no adjustments. Maybe I should add a small dot of locking compound to the thread and all will be well.

I am surprised. I did think about a tonearm part problem when I read your original findings, but I guess I assumed due to its cost/low production, that a part as critical as this would be addressed. But then I believe that I also read this week, something about another expensive tonearm’s part actually changing its shape....
Hard to believe.

Maybe I should add a small dot of locking compound to the thread and all will be well.

Personally I would not accept this kind of solution. If it was me its going back to the manufacturer. I realize that depending on where one lives, in relation to where something is made; could prove challenging from a logistics and time period.

If anything I would try something non permanent first. Maybe a tiny dot of Blue Tac - but Blue Tac also dampens.

To be clear, I’m talking about changes in VTF of +/- 0.05g here so nothing that’s going to do any long term damage to anything. It may be just as much room temperature interacting with the damping in the cartridge, who knows and it’s certainly nothing I’ve ever heard an issue with on listening. Also if I was that bothered I could simply take off the smaller counterweight and adjust only the main weight which has a locking screw, that way no concerns

Personally I find VTF the least important parameter in tonearm setup, unlike alignment, SRA and Azimuth the difference between being perfectly on (to +/- 0.01g say) and accurate to +/- 0.1g has never seemed that big, at least with my Air Tight PC-1. For example on going from the TriPlanar to the Kairos I was able to go from 1.85g to 2.05g, the former had been necessary to get the cartridge to be open and lively on the TriPlanar wheras with the much better controlled Kairos I could take up the VTF into more of the typical manufacturers recommended range and get a better sound without losing energy. And lets not mention my other cartridge the Miyajima Zero which tracks at a whopping 3.5g and shifting things 0.5g or more is no big deal

folkfreak, "changes in VTF of +/- 0.05g"!?!

While I don't pretend to have expertise in such things it seems reasonable that many LPs (i.e. not being perfectly flat) will cause more variation in VTF than that.  As a folk freak, hill and gully rider?

A friend who worked as an engineer in the aircraft industry has a favorite saying, "Don't worry about picking the fly sh*t out of the pepper."

A friend who worked as an engineer in the aircraft industry has a favorite saying, "Don't worry about picking the fly sh*t out of the pepper."

Good one Pryso  :^)

I have this Technics SL1200 that I have loaned out over the years. It has a black Grado on it. It was returned to me a few months ago and it's there staring at me so I got curious. From my earlier post I set it at its lowest VTA setting and took VTF reading, then went to the highest VTA setting. The difference in VTF was about .15 gms. ( 2.00 gm to start and then it dropped to about 1.85gms) But the overhang was way out.
I have tried this in the past on the Dynavector DV505, but you need to be careful with that tonearm. If not careful when adjusting VTA, the heavy arm could come down on its column and maybe toast the cartridge.