Duofold Inner Cap

[brgphilly]

I have been wondering why my Canadian Duofold has a dramatic tendency to dry out. It turns out that the inner cap does not meet the end of the section and I suspect that the resulting gap is the cause of the dry-out. Does anybody know where I can find a replacement inner cap that would meet the end of the section? Alternatively, how can I lengthen the inner cap that I already have? Thank you all, Barry

[Ron Z]

We've seen this in a number of OS Vacumatics and Vac Maximas. The solution has been to machine a bushing that fits snugly in the cap to extend the inner cap, paying attention to ID, OD and length.

[Jamesbeat]

That's weird. Is the inner cap original to the pen?

As Ron Z said, the best solution would be to have someone make an extension.

 

It would be a pretty easy machining job for someone with a lathe.

 

It's actually pretty easy to make a whole new inner cap, as long as the correct threading die is available.

 

I'd consider that only as a last resort because it's best to keep the pen original.

[FarmBoy]

If you are making a new cap you cut the threads on the lathe. Much easier than using a tap.

 

Does the nib crash into the top of the cap? I don't often see a cap where the threads bottom out preventing the section from stopping at the inner cap.

[Jamesbeat]

I'm not sure I agree that single-pointing threads on the lathe is easier than using a die (I presume you meant a die not a tap).

I've made a few of these inner caps in a variety of materials, and using a die is far easier and quicker than setting up for single-pointing the threads.

 

Having said that, I'm sure the threads are some non standard size, so cutting them on the lathe is probably cheaper and more expedient than trying to source the correct die for a one-off job .

[FarmBoy]

The best method to cut threads is likely a matter of perspective. I can certainly agree that unless you have a lathe and the right tooling a tap/die would be easier assuming said tap/die existed or was as close as a hardware store. I've found that in the time it would take me to find a place to order a tap and go through the process I could have cut said thread a few times or more. Still likely a matter of perspective.

I do prefer to cut external (die) thread as compared to internal (tap) threads but I can still hear the machinists I learned from say trust your set up and cut the threads it is only as hard as you want to make it.