Black streaks during hand planing

[tibi]

Hello,

I have started to plane white oak and I have noticed black streaks on the wood. It looks like some metal contamination from my beloved no.5 hand plane. Also, the area behind the mouth continually turned black. I cleaned it with sandpaper but, it started turning black again. I have vacuumed the plane and also made sure that I do not cary leftover particles from the sharpening to the plane.

What might be the cause of this issue?

Thank you.

 

[thetyreman]

could be mineral streaks in the wood itself? or something to do with the tannin inside the wood.

 

[niall Y]

The wood probably isn't as dry as you think it is. This is a problem when working with green oak as all the steel tools turn black because of the tannin- this can then rub off on the wood.

 

[Sgian Dubh]

Tannin in the wood, iron and water are the cause. Common with tannin rich woods, metal planes, and sweat or other sources of water. It's not a problem to worry about. Final polish prepping of the wood removes any black marks. Black marks on the soles of planes can be ignored. Slainte.

 

[tibi]

Thank you very much all, you are right. This is air-dried oak (I am about to use it as my workbench top) and yesterday I trimmed 150 mm off. It has a moisture content of up to 15% near the center. I am again a bit wiser

 

[okeydokey]

Its a workbench top