problem with pressing

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johnnie

Member
Joined
Nov 26, 2009
Messages
18
Location
cumbria, england
Hi everyone, can anyone tell me where I am going wrong when pressing the parts to the Cambridge Hybrid tubes? When I get to just nipping up tight it looks like my ca finish is popping off the barrel slightly and leaving a mark about 2mm around the end of the barrel. My barrels are squared on my disc sander and tubes eased with countersink, then cleaned. Johnnie.
 
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John,
Do you mean the CA you use to glue the tubes in with (dried) or wet CA you are using to hold the nibs and parts on?
 
Not sure if this is the problem or not. Sometimes if you have a little overhang of your CA finish beyond the barrel, when you press fit it puts pressure on the CA finish and sometimes will make it rise up from the wood, leaving a white or cloudy area right next to the piece you pressed in, although I have never seen it perfectly symetrical around the entire tube. If you are not sanding the ends of the finished tube before assembling this could be your problem. Just a thought.
 
Hi Padre, in answer to your question, its the ca finish (10-20 coats of thin) left over night thats doing my head in. This is the bigest pen I have done yet and wondered if the size is a factor. I thank you for your interest. Johnnie.
 
johnnie said:
Hi Padre, in answer to your question, its the ca finish (10-20 coats of thin) left over night thats doing my head in. This is the bigest pen I have done yet and wondered if the size is a factor. I thank you for your interest. Johnnie.
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Cambridge hybrid is a very nice kit and abit on the larger size. It is also a kit that does not leave much material eft after turning to fit the kit. Here is where you need to be dilligent in what you are doing. I will start with your finish. You are using to me way too many coats but if you are compensating for this by over turning the blank then you may get away with it. But remember you are now making what seems like like very little material and making it even thinner. You are adding a surface that does not flex because of the brittleness of its nature.

Next thing to address. Is the tubes being round. I have had on other kits tubes that either have been squashed or something made them oblong and they way I noticed this was when I placed the spacer bar for the barrel trimmer in the tube it would not slide in easily. I now check this all the time before I glue any tube in any blank. Lesson learned the hard way.

Next is the size of the parts and this is where a good set of calipers is so important in pen turning. We can not take it for granted that each tube and each kit part fits exactly. Again a lesson learned the hard way. Need to make sure the fit is not overtight.

Next and lastly is the cleaning of the inside of the tubes before fitting up the parts. Needs to be free of CA and or burrs around the edges from trimming, thus the reamer comes into play. Another valuable tool. Also after doing that many coats of CA you are bound to have buildup on the very edges of the tubes which I like to hit with sandpaper used on the back of a barrel trimmer. A coupl light passes and it will mean a world of difference.

If all this fails then pack all your kits up and send them to me.:smile:
 
Sounds like it could be that tubes that have some type of build up inside from gluing or from so many coats of CA. I am amazed by putting on that many coats, which will make for a very brittle surface with very little, if any, give or flexing. It would help to chamfer the tube before pressing together the parts. Whenever, I have had this type of problem it has been to some minute piece of glue or something on the inside of the tubes.
 
A pressing matter

Thanks all for your information, I take it all on board. I didn,t have a lot of kits John T but I sure wrecked some good looking blanks. Thanks for your time. Johnnie.
 
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