Table 1. Test programme for wood samples.

Testing impact of wood species and direction of wood fibres in relation to kerf on kickback (12 test variants: bolded)	Testing impact of wood humidity on kickback (9 additional test variants: bolded)	Testing impact of wood temperature on kickback (11 additional test variants: bolded)	Testing impact of shape of wood sample surface in contact with guide bar tip on kickback (8 additional test variants: bolded)
W20 T20 1ad; W20 T20 2ad; W20 T20 3ad	W20 T20 3bś; W40 T20 3bś; W60 T20 3bś; W70 T20 3bś	W_ T10 1ad; W_ T0 1ad; W20 T10 1ad; W20 T20 1ad	W20 T20 2bś; W20 T20 2bśr; W20 T20 2bśR
W20 T20 1bś; W20 T20 2bś; W20 T20 3bś	W20 T20 1ad; W40 T20 1ad; W60 T20 1ad;	W_ T10 1bs; W_ T0 1bs; W20 T10 1bs; W20 T20 1bs	W20 T20 2ad; W20 T20 2adr; W20 T20 2adR
W20 T20 1ab; W20 T20 2ab; W20 T20 3ab	W20 T20 1bs; W40 T20 1bs; W60 T20 1bs	W_ T10 3ad; W_ T0 3ad; W20 T10 3ad; W20 T20 3ad	W20 T20 2ab; W20 T20 2abr; W20 T20 2abR
W20 T20 1bs; W20 T20 2bs; W20 T20 3bs	W20 T20 3ad; W40 T20 3ad; W60 T20 3ad	W_ T10 3bś; W_ T0 3bś; W20 T10 3bś; W20 T20 3bś	W20 T20 2bs; W20 T20 2bsr; W20 T20 2bsR
Marking humidity and temperature of kickback samples, e.g., W20T203bsR (humidity 20%, temperature 20 °C)
Marking basic characteristics of wood kickback samples. Note: 1ad = flat sample, place of choice 1 (Figure 3),hard sample:
oak; 2bsr = rounded sample, place of choice 2 (Figure 3), soft sample: pine, large radius of surface having contact with guide bar nose
No.: 1–3	Letter: a or b	Letter: d, b, s, ś	Letter: R, r or —
Choice of kickback samples from wood log (Figure 3):	Sample hardness:	Kind of wood:	Marking curve radius of sample surface (Figure 4):
1	a = hard sample	d = oak	R = big
2	b = soft sample	b = beech	r = small
3		s = pine	— flat surface
		ś = spruce