Ok, I received the SW1 and rod. Put it together, leveled, calibrated. All good. Really nice quality, the app is super easy to navigate. I really appreciate the thought that went in to making this.
So, I started measuring, and it seems like all my measurements are coming out 6-8 points higher than I expect. A Head Pro Tour 2.0 that my friend measured at 329 on a 3-in-1 swingweight machine came out at 336 on the SW1. A Yonex VCP 310 (2019 edition) that I have measured with the manual method at around 322 came in at 330. A VCP 330 (2018 edition) came in at 338, but I was expecting 332 from my own manual measurements. My son's Ezone 100L, which I haven't measured before, showed up as 317 (TW lists the average at 310). I have a few more examples I could list. And it's certainly true that all the other methods of prior measuring might have been inaccurate, but it's striking that all the values I'm generated from the SW 1 are showing up high. What's going on?
I rechecked the calibration, and even did it once more (along with a re-leveling) on a different surface. The swingweight measurements are consistently coming in at the same numbers -- so the machine is definitely consistent. But it also seems consistently high. Not sure what I might be doing wrong. I am releasing with a light hand, I don't have any unusual air currents passing through the room.
Any suggestions on what might be going on here?
I wanted to give a quick update. After noticing that I was getting high swingweights, relative to what I was expecting, @bfroxen
helped troubleshoot the issue, including just sending me a new calibration rod. Great customer service. Anyway, I think I'm now getting accurate results, and the machine is extremely consistent in the number it outputs for a given frame. I'm not sure if I'm getting accurate twistweights yet, but here are a couple of my results. Out of excessive care, I made sure to level the racquet before each measurement. I don't think this really is necessary for swingweight -- the results don't seem to vary in significant measure.
VCP 310 Blue (3 gms at 10/2, leather grip plus OG, gut 1.3 /Ghostwire 1.22): 323 SW, 13.0 TW
VCP 310 Green (Stock with gut 1.3 /Ghostwire 1.22): 323 SW, 13.2 TW
I'm quite pleased that I had these two frames so well matched in terms of swingweight and, apparently, twistweight (but the static and balance are actually quite different, because one is stock while the other has a leather grip and weight in the hoop).
Head Pro Tour 2.0, stock, fb gut 1.3: 334 SW, 13.47 TW
Head Pro Tour 2.0, stock, gut 1.3 /Ghostwire 1.17: 329 SW, 13.49 TW
The swingweights on these PT2.0's are as I had expected, but I was surprised that the twistweights are only around 13.5. TWU lists this twistweight as 14.9!