Pens Cracing During assembly?

[programmergeek]

Ok I am on about my 5th pen and about 3 of them have cracked during assembly. One I cracked because the press what not stright the other one just devloped a crack and the last one tonight was a ebany with a ca finish even used thin CA on the wood to make sure it was had cracked near the center ting during assembly.

What am I doning wrong. Most of the kits I am using are from Rockler 7mm slimline. I have some better kits but I got these to pratice on first. Is it the kit or me. I can understand one every now and then but this si to much.

 

[nava1uni]

You should check and make sure that there is no glue inside the tubing. Do you ream the ends? I have found that this helps when assembling and it helps prevent cracking.

 

[THarvey]

Is it possible you have some glue or epoxy inside the tube? The hardward on the kits is designed to be press fitted. Even the slightest amount of glue inside the tube can cause problems.

Try cleaning the inside of the tube with a small knife or file before turning.

By the way...Welcome to the addiction. Your life may never be the same again.

Tim

 

[NewLondon88]

I think the most common reason for cracking is not removing all traces of glue
in the tubes. WHen you press fit the parts into a tube that has residual glue in
it, there's not enough room for both the glue and the part. So the brass tube
gets pushed out. It expands into the wood, which cracks from the stress.

Before assembly (even before putting the tubes on the lathe) try pushing up through
the tube from the bottom .. use something round with a sharp edge. Most turners
have a favorite tool for this.

When you push up from the bottom, you'll be able to pop out the glue as you scrape
the inside of the tubes. Parts should fit much better afterwards.

ps.. ebony cracks when you look at it wrong.

 

[Wood Butcher]

Not sure where it is cracking or why but I have had some crack due to CA or epoxy glue hardened inside of the brass tube. This makes the part very hard to push in and the extreme pressure generated by too tight of a fit will split the wood or acrylic. Without seeing it that's just an educated guess.
Wood Butcher

 

[bitshird]

Try chamfering the tube before you press the Nibs and finials, also make sure the tubes are clean, no glue, or epoxy, that's what causes most cracks, other than alignment problems, Chamfering will help eliminate a lot of that

 

[Texatdurango]

I would have a very close look at the ends of the blank and make sure the mating pen parts aren't squeezing against the blank itself rather than against the brass tube when you assemble the kit.

This hilites the importance of squaring the ends of the blanks and getting them dead flush with the brass. If one side of the blank is higher than the other, that side will be compressed more than the other when the pen parts are pressed together causing strain on part of the pen.

If you look closely at the assembled pen, even under magnification, can you see a slight gap on one side?

 

[programmergeek]

No spaces In one area it is not quite to the brass by a hair, but that was at the center ring/mechiusum so the press did not hit that. I use a trimmer which is suppose to clean the inside of the barrel by maybe it is not totally, I didn't really check. Can't now unless I can take it apart which is not really possible. Will have to make a cleaning tool forthe insides of the tubes andy sugestions?

 

[bkersten]

No spaces In one area it is not quite to the brass by a hair, but that was at the center ring/mechiusum so the press did not hit that. I use a trimmer which is suppose to clean the inside of the barrel by maybe it is not totally, I didn't really check. Can't now unless I can take it apart which is not really possible. Will have to make a cleaning tool forthe insides of the tubes andy sugestions?

I use a cordless drill with a .38 (7mm tubes), or .45 cal cleaning brush for the Sierra,WallStreet tubes. Really shines them up in no time.

 

[tishtigger]

I use the cheap modeling clay you get at a craft store and before I glue I take some clay flatten it out then use the tube to cut a little clay plug at both ends then i glue. The clay keeps the glue out and after the glue dries I use a skewer to pop the clay out then I do some squaring of the ends and such I haven't had many crack since I started using clay I use the kind of clay that doesn't dry out if I leave it open I think I paid $5 for a 2 pound brick.

 

[mostangrypirate]

everyone has allready mentioned glue. I have also ecountered another problem. I have gotten kits, a batch at a time that were not machined properly. sometimes the parts that are supposed to "press fit" are too large, or the plating added too much to the diameter. you aren't real sure until CRACK!!!!

 

[randyrls]

To join the thread; The brass brushes are a good idea. HF has them and Woodcraft too!

Make absolutely sure you clean all the glue from the inside of the tube. The pen mill will not do the job. Also campher the ends. A (gun) cartridge deburring tool works well for this.

Some materials like Corian will not expand even a little but will crack instead. In that case I gently expand the brass tubes ends before gluing so the fittings are a slip fit, then glue the fittings during assembly.

 

[Munsterlander]

agree with plugging the ends before gluing - i use playdoh, some people use wax, some people use potatoes.

also, when you do check the ends, just know that it takes almost nothing to cause the problem - you might look at it and think it looks fine, but there's still a thin, almost not visible layer in there. gotta get it all out as everyone has stressed. if you plug first, the only thing you'll need wrt glue is an exacto knife.

also, do yourself a favor and get the chamfering tool from AS or somewhere - it really makes a huge difference, particularly if you flatten the end of the brass tube a a bit when you're doing your barrel trimming.

 

[B727phixer]

Is the wood completely dry? I have cracked a couple using green wood.

 

[TellicoTurning]

To join the thread; The brass brushes are a good idea. HF has them and Woodcraft too!

Make absolutely sure you clean all the glue from the inside of the tube. The pen mill will not do the job. Also campher the ends. A (gun) cartridge deburring tool works well for this.

Some materials like Corian will not expand even a little but will crack instead. In that case I gently expand the brass tubes ends before gluing so the fittings are a slip fit, then glue the fittings during assembly.

I'll throw my two cents in too... agree on the glue inside the tubes... I like Tishtigger's idea on the clay.. haven't tried that myself.. usually just clean with a knife. Also like the idea of the brass brushes need to get a set.

On chamfering the tubes... I use a couple of flat bladed screw drivers... if they fit inside the tube and the shoulders hit the edges, a quick turn will take off any burr you've put on when you squared the ends... and no matter how careful you are, you will nick the brass with the pen mill and can leave a slight burr inside the tube..

 

[Rob Eberhard Young]

...or you can use Playdough for the same effect. Always a good idea to plug the brass before gluing.