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How to Avoid Cracked Pen Barrels

On October 8, 2010, in Pen turning, by Eric Anderson

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.

Pen tube cleaning

Use a shotgun bore brush to clean pen tubes

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.


Countersink bit for pen tube
Countersink bit chamfers pen tube


You can see from the pictures below how the countersink bit bevels the end of the pen tube.


Squared pen blank
Pen tube before chamfering



Pen tube chamfered
Pen tube after chamfering


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.

5 Responses to “How to Avoid Cracked Pen Barrels”

  1. Mark says:

    Great idea using bore brushes to clean the tubes.
    What do you use for slimline’s?

  2. […] of pen tube a bit before assembly. Here's a link to an article that talks about this very problem: Cracked Pen Barrels- How to Avoid Them Hope his helps! __________________ […]

  3. Dave Eurich says:

    I’m new at pen turning. I’ve only done maybe 200 pens. I’ve never had a wood Pen Barrel crack but I used to crack the plastics a lot at first. Three things I do have pretty much eliminated that problem. I drill a slightly larger hole. Use a small rasp file inside the tube to remove CA and burs from the ends. Then last just before pressing into the tube I have a small cup of glass cutting oil that I keep a Q-Tip in. I run a very light swab inside the end of the tube. The pieces seem to glide right in. I don’t know why I decided to try the glass cutting oil other than I had it and it’s pretty thin. I didn’t want a heavy oil or to use to much that would run in the tube. Maybe others could try it or tell me if it’s a bad thing.

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