where to buy tubes??

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beck3906

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Aug 13, 2005
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Belton, TX 76513
Use caution when attempting to use tubes purchased from the local hobby shops. The tube wall thickness may be significantly different than the tube wall thickness used for pen blanks. I found the expensive/hard way that nibs and other items do not insert wll into the hobby shop tubes I bought.

You would be wise measuring the tube walls before investing in the hobby shop tubes.
 

mredburn

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Jul 5, 2009
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Fort Myers FL
THe sierra uses a 10.5mm tube. currently I have found no source for 10.5mm tubing in longer legnths. I have contacted K&S engineering but they have discontinued the one tube tha was close to 10mm. If I want to make a longer tube using the 10.5mm tubes I cut one in half and then solder/glue a 10mm(cigar tubes) tube in place and use that. You can buy the 10mm tubes in 10in lengths from different suppliers. WoodnWHimmsies is one of them. Iused that process in the pen in my signature line to make it 5/8ths longer than a regular Sierra/Wallstreet.
 

snyiper

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St Inigoes, MD
Try McMaster-Carr.com or Smallparts.com May get lucky there or find a differnt material for tubes like aluminum.
 

ed4copies

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IF you are measuring to replace tubes, going by the "hole size" will not get you there, from here.

Measure the OD of the tubing that SHOULD be used, precisely. Then look for that size. THEN look at wall thickness, as was mentioned.

"Close enough" will result in crappy pens.
"Precisely correct" will be difficult to find.

Good luck in your pursuits!!
 

ldb2000

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Sep 11, 2007
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Laurence Harbor, NJ, USA.
The average tube size for Sierra's (and clones) is
.409" or 10.37mm in diameter
.009" or .24mm wall thickness
After measuring several different tubes these are the average of them .
You can't just use any size that's close , it MUST be the right size . This is not an off the shelf size . Get Sierra tubes and glue them in to make the length you need .
 

Smitty37

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hmmmmm

IF you are measuring to replace tubes, going by the "hole size" will not get you there, from here.

Measure the OD of the tubing that SHOULD be used, precisely. Then look for that size. THEN look at wall thickness, as was mentioned.

"Close enough" will result in crappy pens.
"Precisely correct" will be difficult to find.

Good luck in your pursuits!!

I would have thought the ID critical for the pressfittings would be the critical dimension rather than OD which can be compensated for by the drill bit.....But at any rate wall thickness needs to be considered, I recently learned what I suppose a lot of folks already knew, that 7mm pen and 7mm pencil tubes from PSI have a different id...(wall thickness). I suspect that's why some of my pens have been tighter fits than others.
 

ed4copies

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Mar 25, 2005
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Hey Smitty,

You will also find PSI's mandrel is a different 7mm from other mandrels

But you are CORRECT----the ID IS more critical, but most of us don't have instruments that will measure the ID accurately. The thickness of the caliper makes measuring the inside inaccurate.

(Thank you Johnnycnc!!!! for the education!!!)
 

ldb2000

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Laurence Harbor, NJ, USA.
The problem with using a thicker tube is the amount of blank that will be covering it . Most pens don't have allot of thickness left to the ends of the blanks and a thicker tube will leave even less .
 

ed4copies

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Mar 25, 2005
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The problem with using a thicker tube is the amount of blank that will be covering it . Most pens don't have allot of thickness left to the ends of the blanks and a thicker tube will leave even less .


Also a thicker tube will not expand as easily as a thinner one. So, when you press fit the parts, particularly the threaded inserts for the nib, it MAY distort or fracture, reducing it's useful life.

In short, stick with the ones that are made for the kits for minimal difficulties!!!
 
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