Every pen turner has experienced it- after going through the entire pen turning and finishing process, you start to press a pen kit component into your beautiful pen barrel and CRACK! It splits! This has got to be one of the most frustrating experiences known to pen turners. I would like to share a few ideas on how to avoid cracked pen barrels during assembly.
Clean your pen tubes
I can tell you from my own experience that one of the most common causes for cracked pen barrels is glue residue left in pen tubes. Even the most minute spot of glue left in your pen tube is enough to expand the brass tube beyond its intended size and crack the thin wood of the pen barrel. So it is imperative that you get your pen tubes absolutely clean.
The best method I have ever used to get my pen tubes totally clean is to run a shotgun bore brush through the tube. To do this, I chuck the bore brush (which comes with a shotgun cleaning kit) in my drill press and then swab out the tube carefully on both ends.
Ever since I started using this method I have drastically reduced cracked pen barrels during assembly.
Chamfer your pen tubes
Another technique for reducing cracked pen barrels is to chamfer the ends of your pen tubes. I don’t always do this every time I turn a pen, but if I’m particularly worried about it, I will use this method. By “chamfer” I mean to bevel the ends of the tubes to make them slightly larger on the ends. The purpose of this is to enlarge the opening of the pen tube so that the component fit more loosely for the first bit of the tube.
The easiest way to do this is to use a countersink bit in your drill press or by hand. It doesn’t take much pressure from the bit to remove brass from the tube, so use a light touch.
You can see from the pictures below how the countersink bit bevels the end of the pen tube.
Use a larger drill bit
Often it helps to use a slightly larger drill bit so that your pen tube fits more loosely in the blank. Obviously you have to be careful not to make the hole too large, but sometimes just a few thousands of an inch can make the difference between a cracked pen barrel and a successful project.
Press pen kit components straight
I suppose this should go without saying, but you must be very careful not to get your pen components started even slightly crooked as you assemble the pen. Take your time to make sure the component is in line with the pen before applying much pressure.
Got anything to add?
These are some of my best tips to avoid cracked pen barrels during assembly. Now I would like to hear from all of you and learn what tricks you use to avoid cracking your pen barrels. Maybe you can help your fellow pen turners avoid this frustrating problem. Please email me and let me know your tips and I will certainly consider posting them. I look forward to hearing from you.