Tube length tolerance??

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Jimbes

Member
Joined
Jan 13, 2017
Messages
12
Location
Erie, Colorado
CSUSA Jr. Statesman II. I bought some replacement tubes to have on hand if I needed to make some while waiting for kits to arrive. I just messed up one by going a bit too strong on my bandsaw while trying to get close to truing up the tube to the blank. Then I started measuring.

I have a difference of 2mm in kits from CSUSA. Two tube sizes: 48mm/53mm measured on digital Mitutoyo calipers. Others are 48/55 (all the replacement tubes), and 50/53 (brand new kit just received yesterday).

I expect tolerances for different kits might be more or less critical, but I'm wondering if a couple millimeters on the length of the tubes is "normal".

My screw up ended up at 46/55 and I'm wondering how that might effect my final product. I think it won't matter much (other than making the pen 2mm shorter) for this kit (i.e. the end cap doesn't touch the writing part). I am to deliver 4 "identical" pens to a customer, so I'm not sure this will be "tolerable" to me. :)

Jim
 

magpens

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Joined
Feb 2, 2011
Messages
15,913
Location
Canada
48mm/53mm are the correct tube lengths for the two tubes of a Jr. Statesman.

Lengths different from those by as much as 2mm would be pushing the limits of acceptability in my opinion and I think you should question the supplier.

As far as functionality goes, for a rollerball the 2mm may not matter. . There is a spring in the end cap which can take up some slack for a tube length with is too long. . You could even stretch the spring a little if you had to. . For a tube length that is too short, that spring will be compressed a bit more than it normally would, and, again, things should be OK.

You do need to be concerned a bit about the overall appearance of the pen though.

Another concern is the length of the cap tube ... you don't want the rollerball tip contacting the inside of the cap finial.
You can check for that possible problem using your calipers.
 

its_virgil

Member
Joined
Jan 1, 2004
Messages
8,101
Location
Wichita Falls, TX, USA.
There are lots of Juniors being sold. Jr. this and Jr. that. some have tube lengths the same as the original Jr. Gent/Statesman Version II and others have a longer barrel tube(the smaller diameter). When ordering Jr tubes I ask which junior. Some vendors say it doesn't matter but those are not my thoughts. I stick with the vendors that sell both sets and know the difference. It is more difficult to keep up with all of the tube sizes these days. Even some of the charts and lists floating around have incorrect sizes. Maybe a typo...maybe not.
Do a good turn daily!
Don
 

Edgar

New Member Advocate
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Feb 6, 2013
Messages
6,890
Location
Alvin, TX 77511
There are lots of Juniors being sold. Jr. this and Jr. that. some have tube lengths the same as the original Jr. Gent/Statesman Version II and others have a longer barrel tube(the smaller diameter). When ordering Jr tubes I ask which junior. Some vendors say it doesn't matter but those are not my thoughts. I stick with the vendors that sell both sets and know the difference. It is more difficult to keep up with all of the tube sizes these days. Even some of the charts and lists floating around have incorrect sizes. Maybe a typo...maybe not.
Do a good turn daily!
Don

Most such errors are indeed typos - some on our part and some in the supplier documents that are the primary source for our information. I have a list of several corrections that need to be made, but I'm sure there are more that we aren't aware of yet.
 
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