Cracking blanks

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M. Newell

Member
Joined
Feb 1, 2012
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32
Location
Green Bay, WI
Hello everyone,

I've made hundreds of pens with no problems. Lately when putting pens together i'm cracking the acrylic blanks. Store bought blanks and home made. Any ideas welcome.
Thanks in advance, Mike
 
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Glue residue left inside the tube is the usual culprit. Some people will use a file or abrasive on a dowel to remove a little from the inside of the tube to reduce the press fit.
 
I just looked closer at some blanks that i had ready to turn. Even though i used a barrel trimmer there was still a small amount of glue in the tube.

Thank you all for the ideas.
 
Reaming out the brass tubes by 1 - 2 thou just before assembly has been a blank-saver for me. Sometimes the brass hardware pieces are plated, increasing their thickness. Here's a picture of a set of adustable reamers that I have found extremely worthwhile.
After reaming you may have to use epoxy to hold the pen parts together.
 
Some parts are just plain too tight to press. When you press in a part, it expands the tube a tiny bit creating the press fit.
I file/sand the inside of the tube so the part slips in almost of the way and add a touch of epoxy with a toothpick. Not enough to squeeze out.
Acrylics and other blanks don't like to expand when the tube is swelled. They say uncle with a crack. Most wood is more forgiving.

On the other hand, I have seen parts so loose that they slide in by hand and need glue to hold them in.
 
M. Newell said:
I just looked closer at some blanks that i had ready to turn. Even though i used a barrel trimmer there was still a small amount of glue in the tube.

Thank you all for the ideas.
Click to expand...

I plug my tubes with non-hardening clay from an art supply store to keep epoxy out of the tubes.
 

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qquake said:
M. Newell said:
I just looked closer at some blanks that i had ready to turn. Even though i used a barrel trimmer there was still a small amount of glue in the tube.

Thank you all for the ideas.
Click to expand...

I plug my tubes with non-hardening clay from an art supply store to keep epoxy out of the tubes.
Click to expand...

I got a pound of dental base wax on eBay (probably a "lifetime supply") for $12.00. It works great for plugging tubes. I tend to go heavy on the epoxy, so it's a necessity for me.

I have learned that HARD WAY that if a pen component is going together "too hard" to stop and find out why--ruined a nice Atrax barrel this way.
 
mecompco said:
I got a pound of dental base wax on eBay (probably a "lifetime supply") for $12.00. It works great for plugging tubes. I tend to go heavy on the epoxy, so it's a necessity for me.

I have learned that HARD WAY that if a pen component is going together "too hard" to stop and find out why--ruined a nice Atrax barrel this way.
Click to expand...

I used to use base wax, but the clay works better for me. The base wax used to get hard after a while.
 
Great help! Thank you all!

Magpens where did you get that set of reamers? Looks like time for some new tools....break my heart

Im definately going to Michaels for some clay.

Thanks again everyone.
 
I clean out my tubes with a smaller piece of brass tubing.. The smaller tubing is usually given a sharp end and a little flare with a 3 or 4 flute countersinking reamer.
 
Some tips

I use a thin pass of grease on the inside of my tubes before sticking them to my blanks. so any CA or epoxy that enters the tubes will easily slip off when using my reamers to square the blanks. Moreover, be very careful when pressing the pen parts. Pressing them in at an angle will cause cracks. Some kits i got had this problem where the pen parts press in tight on the tubes thus causing the tubes to expand and causing the cracks. A little sanding for the pen parts with 150 Grit sandpaper solved this problem. Good luck.
 
Pens

M. Newell said:
Hello everyone,

I've made hundreds of pens with no problems. Lately when putting pens together i'm cracking the acrylic blanks. Store bought blanks and home made. Any ideas welcome.
Thanks in advance, Mike
Click to expand...

Is it possible your drill bit has worn a little bit...???
 
Lately I've had some problems with slimlines, I got a batch of Gun metal and a few chrome that were just a little to heavy on the plating and would cause my pens to crack during assembly.

I also found the batch to have the clip snap off at the top, I called Both suppliers and they replaced the clips for me but still 60 clips out of 100 pens was not easy to swallow, specially since clients started to complain.
 
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