Randy_
Member
There is some discussion currently about the tubes for the two Sierra kits and if they are interchangeable or not. The main reason for the question is that the Sierra Button Click is a relatively new kit and spare tubes are not yet available.
I just got some click kits from BB and measured them up to see how they compare with the tubes from the Sierra twist kit. The short answer is the tubes from the two kits are different and not completely interchangeable.
Both tubes have the same ID/OD in the neighborhood of 0.390â€/0.408â€; but the lengths are different. The twist tube is about 2.208†long and the click tube is about a 1/4†longer at 2.423â€.
Now, most folks know that the click pen will accept either a standard Parker refill or a uni-ball 65873 refill while the twist pen will “ONLY†take the Parker. Since the uni-ball refill is about 0505†longer than the Parker refill one might immediately jump to the conclusion that the two tubes should differ by that amount. I did and I was wrong. The wild card, here, is that the propelling mechanism is different for the two kits so the pen geometry is different as well. To a certain extent, the length of the refills is immaterial. Based solely on refill length, you would expect the twist kit tube to be 0.5†shorter than the click kit tube. But since there is only about a 1/4†difference in tube lengths, it is apparent that the twist transmission is not quite so efficient in the use of the long-axis space.
What all of that means is if you mess up a tube from a click pen kit, you can’t just snag a tube from a Sierra twist kit and move on. You have two options to resolve the problem and both require a little extra effort. To keep the click pen in its original configuration so that it will accept either refill, you will need to cut the twist tube in half. Then you can insert the two pieces into a blank from each end and leave a short untubed section in the middle of the blank. According to my calculator, the untubed section will be a little more than 0.215†long if you cut everything perfectly. You would be safer to cut the blank a little longer than the required 2.423†so you have a bit extra for squaring the ends.
If you don’t care to retain the option of using the uni-ball refill and want to use the pen as strictly a Parker pen, you can use a blank that is about 1.918†long. This means you need to trim about 0.290†from a standard twist tube or make up a slightly longer blank and then trim it to the correct length.
I think all of the numbers are accurate; but, if someone else would like to double-check these figures, that would be great. I would not recommend that anyone use these exact figures as we all know there is some variation from kit to kit. If you have the need to make up a click right away and have messed up a tube, you should probably measure all of your parts to be sure there are no differences between your kit and mine.
To tell you the truth all of the above sounds like a heck of a lot of work to me for not much benefit. It was fun to take the measurements and interesting to do the calculations and I needed the measurements for my pen chart, anyway. But, if it were me, I would just buy another kit to make up and throw the tubeless one in a drawer until Bill gets his spare tubes in stock and then just buy a couple of replacements.
Obviously, using a twist tube can work for those who are so inclined; but I think most of us would be better off taking the easy out!!
I just got some click kits from BB and measured them up to see how they compare with the tubes from the Sierra twist kit. The short answer is the tubes from the two kits are different and not completely interchangeable.
Both tubes have the same ID/OD in the neighborhood of 0.390â€/0.408â€; but the lengths are different. The twist tube is about 2.208†long and the click tube is about a 1/4†longer at 2.423â€.
Now, most folks know that the click pen will accept either a standard Parker refill or a uni-ball 65873 refill while the twist pen will “ONLY†take the Parker. Since the uni-ball refill is about 0505†longer than the Parker refill one might immediately jump to the conclusion that the two tubes should differ by that amount. I did and I was wrong. The wild card, here, is that the propelling mechanism is different for the two kits so the pen geometry is different as well. To a certain extent, the length of the refills is immaterial. Based solely on refill length, you would expect the twist kit tube to be 0.5†shorter than the click kit tube. But since there is only about a 1/4†difference in tube lengths, it is apparent that the twist transmission is not quite so efficient in the use of the long-axis space.
What all of that means is if you mess up a tube from a click pen kit, you can’t just snag a tube from a Sierra twist kit and move on. You have two options to resolve the problem and both require a little extra effort. To keep the click pen in its original configuration so that it will accept either refill, you will need to cut the twist tube in half. Then you can insert the two pieces into a blank from each end and leave a short untubed section in the middle of the blank. According to my calculator, the untubed section will be a little more than 0.215†long if you cut everything perfectly. You would be safer to cut the blank a little longer than the required 2.423†so you have a bit extra for squaring the ends.
If you don’t care to retain the option of using the uni-ball refill and want to use the pen as strictly a Parker pen, you can use a blank that is about 1.918†long. This means you need to trim about 0.290†from a standard twist tube or make up a slightly longer blank and then trim it to the correct length.
I think all of the numbers are accurate; but, if someone else would like to double-check these figures, that would be great. I would not recommend that anyone use these exact figures as we all know there is some variation from kit to kit. If you have the need to make up a click right away and have messed up a tube, you should probably measure all of your parts to be sure there are no differences between your kit and mine.
To tell you the truth all of the above sounds like a heck of a lot of work to me for not much benefit. It was fun to take the measurements and interesting to do the calculations and I needed the measurements for my pen chart, anyway. But, if it were me, I would just buy another kit to make up and throw the tubeless one in a drawer until Bill gets his spare tubes in stock and then just buy a couple of replacements.
Obviously, using a twist tube can work for those who are so inclined; but I think most of us would be better off taking the easy out!!
