SG 250 Wheel sideways imbalance / T8 owners in Tyrol, Salzburg or Wels?

[Thomas S.]

Hello,

I started grinding again after a long break.

I (again) noticed a "large" sideways imbalance. It's actually always been there, but now it "bothers" me more. In the Tormek manual page 164 it says +/- 0.5mm (total 1.0mm). The stone was not used very often and was pulled off two or three times (diameter approx. 246mm).

I also looked at Beaker's link in the topic "There is a regulation for mounting the SJ-250" and tried it.
I tilted the machine on the side of the leather wheel and put the grinding wheel horizontally on the "standing" shaft and fixed it. I also loosened the stone several times, twisted it a bit and tightened it again. The result has not changed significantly.

Now I'm not sure if this is an operator error (clamping error), inaccuracy from the stone, or a bent shaft.

I lightly "polished" the stone with the SP650 on the receiving surface, also thoroughly cleaned the nut, washer and shaft!

Experiment 1: I switched on the machine, put a permanent marker on the case and slowly approached the stone. This marked the "biggest" imbalance. I then switched off the machine, loosened the stone, twisted it a few degrees and tightened it. Repeat the test with a different colored permanent marker. I repeated this process 5 times on the inside and outside. The result was that the largest "imbalance" was always marked in the same quarter of the disc. So, in my opinion, I can rule out a "bent" shaft. It is also interesting that the largest deflection is offset from the inside to the outside by 180°.

Experiment 2: I looked for the points with the two largest and the smallest distance between the grinding wheel (inside) and the housing and measured them 4 times. The stone was re-clamped between each measurement.

Results:
1: 6.2mm / 6.3mm / 5.2mm = diff. 1.1mm
2: 6.0mm / 6.1mm / 5.4mm = diff. 0.7mm
3: 6.4mm / 6.5mm / 5.2mm = diff. 1.3mm
4: 6.1mm / 6.2mm / 5.5mm = diff. 0.7mm
Two results are OK, two less.

Maybe there is a T8 owner in the forum who lives near Innsbruck (Tyrol). I'm also in Salzburg and Wels every now and then for work. It would be cool if someone there was willing to swap the discs for a quick test and see if it made a difference.

But maybe I'm just being too picky?

Best regards
Thomas

[RichColvin]

Thomas,

I do not mean to come across as rude, but I must ask: if the cutting surface is not varying (especially after truing the surface), why does the side-to-side movement matter?

Rich

[Thomas S.]

Hello Rich,

you're probably right and I'm getting into something that isn't actually a real problem. The more you "get angry", the greater the imbalance 😉
What could possibly be annoying is that you drag too far towards the handle and "wobble" into it. Of course you can also protect it with tape or stop grinding earlier.

I should probably just sharpen and mess with it less (like I used to).
Maybe I shouldn't expect too much when it comes to lateral rotation?


Thanks
Thomas