Hello to everyone.I did inspection at my collection and noticed that some tubes T12 have scratches on glass in the middle of the tube?These can be felt under nail.Should I worry,and why this happens,tubes are in box and beetween them is paper,tubes are stable and static(not moving).

I can't say I've noticed, but I almost always use cotton gloves when handling lamps. I picked up the habit when handling quartz lamps, as of course these do not like to be contaminated with oils from bare hands, and it also helps with avoiding fingerprints on the glass, which is another of my pet grumbles. But it doesn't seem like it should happen in normal handling 

Interesting, I have a pair somewhere for handling film negatives but I never thought to use them for lamps. Anyway I got mine from the pharmacy of all places.

I think it's relatively normal.  I have at least a handful of T12 and T8 lamps with scratches, some of which I can feel with my nail as well.  I'd probably find more if I inspected my tubes closer.  I've never had a lamp fail because of them, as far as I know.

Yup, I've had a good number of them as well. 

I have had light scratches on tubes before. Seems to not affect it on tubes except damaging the etches. I have seen some have it from factory. Since yours are on the middle, there should be no problem.

Thanks everyone.I turn on tubes and inspect them,there are no problems,they still hold vacuum.I keep them in box and they are safe.Honestly I was curious to see why is this happening and are there people with same "problem".

could it be the mercury beads inside that roll up and down and take off some phosphor?

I've had scratches on my fluorescent tubes as well, both T8 and T12. I've even had an older T12 34w GE Watt-Miser that had a noticeable crack
near the end cap... still worked as if nothing was wrong.

Scratches on the outer surface are entirely normal and harmless.  It’s a result of modern high speed production machines that throw the glass between the different mechanisms and inevitably cause some damage.  But it is impossible for these external scratches and cracks to grow. 

During manufacture the glass outer surface is heated in a flame containing sulphur dioxide gas, which reacts with the sodium carbonate component to form sodium sulphide dioxide which vaporises, and carbon dioxide.  There is no reaction with the silica component of the glass, so the result is to increase the % silica content - it basically turns the outer skin if the glass into quartz, which is incredibly strong.  The softened glass then passes through a so-called Hitachi blower which freezes the outer skin very rapidly, before the inner surface cools.  When the inside cools it pulls the outer skin into a state of compression - and it is impossible for glass to crack while in compression.  Conversely, the slightest scuff on the inner surface (which is in tension) would cause the glass to shatter.