New here, hoping to learn more about turning pens. Had a question I was hoping I could find the answer to on here. Does anyone know the actual size of the tubing referred to as 8mm used for pencils? I purchased some 8mm brass tubing to try something and it was too large. I measured my 7mm pen tubing and find it is slightly smaller than 7mm, roughly .25mm smaller, so I was wondering if the 8mm brass tubing used for pencils and penmaking is actually slightly smaller as well. Thanks!