Pen Cracks....

Re: Pen Cracks....

Fred in NC

>Tony:

There can be several causes.

1. The tube fits too tightly in the hole. This can be caused by wood that is still not dry enough, or has stresses left in it. The tube should slide easily in the blank with the glue on.

2. The end was not square. This is a common cause of many troubles in pen making... it also causes the wood to turn off center.

3. WATCH THIS ONE! After turning the barrels, I clean the inside the the tube at both ends. I use a size D drill bit epoxied in a wood handle. If there is any glue residue inside the tube, the brass can expand a little, and the wood will crack at the ends.

4. When assembling the pen, make sure all fittings go in straight. Pushing the fitting in crooked can also expand the brass tube and cause cracks in the barrel.

Don't ask me how I know !!!

Fred

Re: Pen Cracks....

Greg W. in NC

>Tony,

I suspect the problem is you're using green or wet wood - wood that's not finished drying out. Some woods take forever, or never really get dry (i.e. ebony.) Most of the pens have such little wood left around the tube that if it moves at all from drying, it'll crack. You might try making sure your wood is dry (7- 10%.) Also, if your pens are exposed to drastic humidity changes, that can cause cracking as well, after the pen has been assembled.

The other items Fred mentioned are valid points, but usually those issues will cause cracks upon assembly.

Re: Pen Cracks....

Fred in NC

>Greg:

This what I do with wood like ebony:

1. Drill the hole in the blank.

2. Mount it on a tube... NO GLUE !

3. Rough turn it into a cylinder a big bigger than finished size.

4. Take them out of the mandrel and tube. Let it dry for a few days. The internal humidity now has a place to escape, and also some can escape from the outside.

5. Run the drill through the hole again. If the wood has shrunk, this will slightly enlarge the hole.

6. Glue the tube, square the ends, and turn the pen.

I must say,however, that most of my cracks were due to glue etc. inside the tubes. I did not notice some of these cracks until later, so I blamed the wood.

Burls and ebony are especially prone to cracking. Russ Fairfield uses a slightly larger drill on those, I think he uses a 9/32" drill bit.

Re: Pen Cracks....

DWFII

>Hard as it may be to believe, sometimes the parts--like a finial reciever--going into the pen are just a bit too large for the brass tube. Sure, the part should fit snug, even tight--tight enough to keep it from coming out--but what's the tolerance? A bit too much coating on the part and suddenly it's expanding the brass tube as it is pushed in...and that can happen whther it is pushed in straight or not. Ten to one your cracks start at the end of the blank that has been turned the thinnest and has a very tight fitting part.

I got this tip from a long time pen turner over on Yahoo penturning group: Sand the part down a bit. Sand the tube, inside, down a bit. And if the part ends up fitting a hair loose, use epoxy to glue it in place. Better to do that than loose the pen and the wood altogether. I do that on all my Euro FPs especially at the finial end. I hate cracks.

DWFII

Re: Pen Cracks....

DW

>... also look at the heat that is caused from sanding/finishing. Depending on how you sand and finish your pens, you might notice some serious heat that can cause the pen to crack when it cools off...

my2bits

DW

Thanks all!

Tony - Memphis

>Lots of good info. I was just looking at a mallee burl pen I finished a coouple of weeks ago (beautiful wood). Funny thing is, the bottom is cracked like crazy, but the top is not. Makes me think I did something different. Wonder too if maybe I clamped the blank too hard while drilling, didn't clear the shavings enough and created heat, or both!?! This is a fairly recent phenomena. I'll have to keep messing with it. Thanks again.

Tony