Another kitless, threadless cap pen

[rixstix]

Finally comfortable with dimensions. Need to work on the order of operations. It's a bit difficult to hold the cap without threads once it's been parted. If only they made rubber ER32 collets

Didn't think about toolmarks on the insides until I thought I was finished. The cap has an internal taper instead of thread, making a press/twist type of fit. The body is tapered on both ends so the cap is postable.

Now to move to a more figurative blank.

Comments, critique & suggestions for improvement greatly appreciated

 

[Displaced Canadian]

It looks good. How does the friction fit work?

 

[rixstix]

So far pretty good. I've been carrying the first one for a few weeks without hiccup or scratch.

2 degree/4 degree included taper is intended to fit like a morse taper (self locking). It's gradual enough to not be too noticeable on the body ends. Works pressing, clockwise or counter clockwise twist. Much easier to cut once I acquired a boring tool to fit inside a 27/64 hole. In theory, it should be as airtight as a multistart thread for fountain pen design. My fiber tip hasn't had a hiccup yet.

 

[duncsuss]

A recent issue of American Woodturner (the AAW magazine) has an article detailing how to make a custom collet chuck using PVC plumbing compression couplers and turned wooden collets.

Or you could create a thin "collar" using some material like PEEK which will keep the jaws of the ER32 collet from marking your part.

 

[rixstix]

A recent issue of American Woodturner (the AAW magazine) has an article detailing how to make a custom collet chuck using PVC plumbing compression couplers and turned wooden collets.

Or you could create a thin "collar" using some material like PEEK which will keep the jaws of the ER32 collet from marking your part.

What a novel idea.... sorta like a "Duh" moment. Thanks for jogging my brain cells. I might even have a piece of delrin lying around to make the first collar/liner.

Thanks Duncan

 

[derekdd]

I really like the profile of this pen, particularly the tip coming off the lower tube.

Fun blank, also.

 

[duncsuss]

What a novel idea.... sorta like a "Duh" moment. Thanks for jogging my brain cells. I might even have a piece of delrin lying around to make the first collar/liner.

Thanks Duncan

I can't take the credit for it (well, I s'pose I *could* ... ). A Belgian pen maker on FountainPenNetwork described his technique to swage silver cap bands into a groove on his pen caps several years ago - it avoids having multiple layers of material (such as a tenon onto which you slip the band and then follow up with a collar to hold it in place) so the cap doesn't become bulky. He used PEEK, which is ridiculously expensive, but I figured a couple of inches of 3/4" material wouldn't break the bank. I don't know if acetal has the same mechanical properties, but for your application I'd say the only major concern would be ensuring the inside bore is well smoothed - maybe ream or sand to a high grit after drilling.

(FWIW - I tried swaging a couple of times. I need far more practice to make it a real success, you're by definition working blind as you crank the collet chuck tighter to seat the band and it's easy for things to mis-align. The second one was a big improvement over the first - but Richard Greenwald, who was my source of sterling silver bands has retired, not sure if I want to make the leap into silversmithing and make my own.)

 

[rixstix]

@duncsuss yep, I wish I had bought a bit more when I heard Richard was retiring.

Soldering or fusing jumprings made from square wire might be the easiest route but they're not true to the world. There's about a 6° twist due to the nature of the beast.