Tony's Pens
Member
I have learned that if your pen kit come from Craft Supplies it needs a hair bit small hole for the brass tubing than what is suggest. If it says to use a 7mm drill bit you will find that the pen blank and brass tube has more slack than what you want. I use a size "I" drill bit for all of my pen kits that require a 7mm hole. This is just under sized so the brass tubing will have a better fit. Of course you don't want it tight because you will split the pen blank when you press the kit together. Mine slides in and out with just a tap on my hand. Example: Craft Supplies instructions says to use a 25/64 drill bit for their Cigar pen kit. I use a size "W" drill bit. This makes the brass tubing have a little better fit. I have placed a link below of a Drill Bit Size Chart. You can use it to know what size drill bit to go down to for a better fit for your brass tubs. Scroll down about half the page and you will see the size 7mm and then look right above the previous size and you will see a size "I" bit. Hope this helps and not confusing.
http://www.carbidedepot.com/formulas-drillsize.htm
http://www.carbidedepot.com/formulas-drillsize.htm