Pen barrel cracked

[Nick Fournier]

So, I'm pretty new to turning and turning pens in general, but I have a question. Of the pens I've turned, one of the pen barrels has recently developed a crack. Does anyone know why or how that happens? Could it have started when I inserted the cap into the pen?

The picture below tries to show the crack, it starts at the top of the barrel and continues down. Since it's the first pen I have turned, I'd like to save it -- so I was going to try and use CA glue to hold it together.

Any suggestions on how to prevent this in the future would be appreciated.

[George Clark]

Was the wood dry?

[David Christopher]

maybe you got it too hot while sanding

[Nick Fournier]

I believe it was dry. It was a random purpleheart blank I had picked up in a group of blanks. It wasn't a large blank, so but I don't think there was a crack after I drilled it.

[Ken Fitzgerald]

A couple of ideas....

1. as stated it could just be the wood wasn't dry

2. there was a burr at that end of the barrel and when the cap nut or cap was pressed in, it caused the barrel to swell at that end and caused the wood to fracture.

3. too much heat during finish, buffing etc. could help cause it too.

[Fred Omer]

Nick, I would agree with Dave that it could have cracked from the heat build up from excessive sanding. Another possible cause could be if you did not get the inside of the brass tubes cleaned out completely, you could have caused it to crack because the brass was expanding once you pressed in the parts. I always use a chainsaw file to clean them out once the glue has set up after gluing in the tubes. Hope this helps. Fred.

[Bernie Weishapl]

Ditto what Ken said. I had one crack on me one time from a burr inside the barrel. When I pressed in the part it cracked.

[David Drickhamer]

It's possible there was some CA inside the tube or you may have started seating the cap crooked.

[Nick Fournier]

I figured it could be any of those -- I'm thinking it was most likely an assembly issue. At this point, I really don't have a good assembly method, I just use two blocks of wood and try and push. Unfortunately, that tends to eventually involve a hammer.

I think I need to find a better way to assemble, but don't want to spend the money for a pen press.

[Jeff Nicol]

One thing I have learned is that Purple heart is brittle and will have fine hairline cracks in it that sometimes don't show themselves until a finish is applied. All of the suggestions so far are spot on, but before you are ready to apply the finish on the mandrel put some lacquer thinner or acetone or DNA one to see if there are any flaws that show up. Then this is the time to get out the thin CA and cover the whole thing to stablize the pen tubes.

On the putting the pens together, I have used the Quick clamps with the little pistol grips to slowly sqeeze the parts together and the rubber on the jaws protect the pen parts. The thing is to maintain straightness of the parts when pushing them together, if a piece is crooked that will create pressure and crack things very easily.

Good luck and keep working at it,

Jeff

[bob svoboda]

I cracked one with too much pressure while pressing the end on the cap.

[Paul Douglass]

It could also be it just cracked. I've made around 100 pens and maybe 3 have cracked. I have always figured it was one of the reasoned mentioned above or just part of life.

[Tom Seaman]

I chuck a bolt with a flat head in my drill press and use that to press pen parts together. Just use something hard (like a maple block) underneath it to keep it from digging in.

[David E Keller]

I chuck a bolt with a flat head in my drill press and use that to press pen parts together. Just use something hard (like a maple block) underneath it to keep it from digging in.

Ditto... It works great.

[Mark Hix]

If the blank is hanging over the lip of the tube, it could cause it to crack when you assemble it....along with the reasons above. I would wager a small sum that the reasons you got were from those of us that have experienced them.

There are alot of ways to press the parts together. I use my vise on my bench. You can use a clamp or make a simple pen press out of scrap wood.