Push on caps

[hertzogcraig]

Has anyone done any kitless pens with push on caps instead of threaded? I'm just curious if this is doable and if you have, how did you do it? I'm assuming you'd have to use and oring and possibly a detent for the oring.

 

[rixstix]

I have been making threadless caps. No O-ring. No detent.

Locked taper using matching 2 degree taper on the cap and body. Think about how a morse taper holds. Force required to separate cap/body 5-9 pounds. Bubble tight to at least 15 psig. I also taper the end of the body so that the cap is postable (if desired). Cap can be removed by pulling, twisting clockwise or twisting counterclockwise.

I focus on ballpoint & rollerball mainly because my budget doesn't allow for me to keep FP nibs/feeds and due to my location in rural South Dakota. Drilling the section to accept a FP feed would only be using a different thread

Locked taper example

 

[hertzogcraig]

I have been making threadless caps. No O-ring. No detent.

Locked taper using matching 2 degree taper on the cap and body. Think about how a morse taper holds. Force required to separate cap/body 5-9 pounds. Bubble tight to at least 15 psig. I also taper the end of the body so that the cap is postable (if desired). Cap can be removed by pulling, twisting clockwise or twisting counterclockwise.

I focus on ballpoint & rollerball mainly because my budget doesn't allow for me to keep FP nibs/feeds and due to my location in rural South Dakota. Drilling the section to accept a FP feed would only be using a different thread

Locked taper example

View attachment 372030

Awesome, thank you. I'm in the same boat, can't afford triple start tools right now and how uncapping my pens with single start threads. Been wanting to try this for a while now, but didn't have a clue where to start. Guess now I need to figure out how to do the tapers.

 

[rixstix]

Guess now I need to figure out how to do the tapers.

Metal lathe. Angle blocks to set a repeatable angle. TIny boring tool to get inside sub half inch holes.

Multi start tap/die is cheaper than the lathe AND tools.

 

[hertzogcraig]

Metal lathe. Angle blocks to set a repeatable angle. TIny boring tool to get inside sub half inch holes.

Multi start tap/die is cheaper than the lathe AND tools.

Luckily, I already have the metal lathe, bought it before my wood lathe to make pipes. I've just never worked with the angles before. Do you by chance have any pics of the boring tool and blocks that you use?

 

[rixstix]

Boring tool is similar to this one 5/16" right hand boring (there is a 1/4" but the min diameter bore is actually larger than the 5/16")

Boring tool insert is CCGT 21.51 CCGT 21.51
Angle Block set is Angle block set

Inside taper lathe turning Forward

Outside taper lathe turning REVERSE

 

[hertzogcraig]

I'll have to give this a shot in the next few days. That's actually the boring tool I've already got so I'm good there. I'm sure I'll have a lot more questions lol

 

[TonyL]

i like the concept simply for convenience. well-done.

 

[Penultimate]

Greetings, you can buy fountain pen nibs with a snap cap feature. I think I bought some cap parts without the nibs for a roller bal I made. Milan's pens sells some. https://www.milanspens.com/product-page/fh-231
I was successful making my own part from polypropylene but went with the ready made part. With your metal lathe you can turn the edge that engages with the snap cap.

 

[hertzogcraig]

Greetings, you can buy fountain pen nibs with a snap cap feature. I think I bought some cap parts without the nibs for a roller bal I made. Milan's pens sells some. https://www.milanspens.com/product-page/fh-231
I was successful making my own part from polypropylene but went with the ready made part. With your metal lathe you can turn the edge that engages with the snap cap.

Awesome, I'll look at this as well. Thank you