I looked all over the web for a printable head scratcher.  Finally decided to make my own.  This one can be printed at 10% infill. You will need to print 6 bars .  I am using a 6x6 build plate and all 6 of these fit on the plate at once.  I would suggest that you print the bars with skirts.  My first attempt at printing the bars, they warped a little near the end of the print and made a mess.  When I printed them with 4 shell skirts they stuck to the build plate and printed fine.   I made these bars to fit easily into the handle and you will need some CA or epoxy to glue them in.   I used 5 minute epoxy and when when the glue dried I did an acetone vapor on the whole thing and it turned out beautifully.   One more thing and this is important:  Lightly sand the tips so that they don't scratch your skin!