automatic probe punch

[gibbon]

I saw some years ago an autmomatic punch device that delivers a spring loaded punch at a consistent force. It was used to record the resistance at 10mm intervals of a steel probe entering a tree. This could be using in a simialr way to a resitograph to map areas of decay. Are these still available? if not where could I find a device which delivers a consistent force to use in a similar application?

[Marcus B-T]

Google destructive wood testing, telegraph poles. They are available still on the net I used one in some research trouble is that you only find decay near the surface or you drill quite large holes in the trees, which sort of defeats the object.

[gibbon]

Sorry no luck still, do you have a link? Surely to could make up a narrow probe .5mm wider than a narrow twist drill? Or is there some other reason why it would need to be a larger hole?