Initial sketches of my first pen design

[AdventiveIowa]

Starting to lay out sketches for the brass pen I'm going to make. These are just my initial thoughts, I might change them up a bit when I actually get to turning, I mostly just wanted to figure out what my OD was gonna be.

Going to use a JoWo #6 nib unit. One of the key features I want to build in is a small lip for O-rings on the interface between the section and the body as well as the body to the cap. This is because I'll be making this out of Brass, and I don't want it to come undone. I guess I could put washers in somewhere, but the o-rings will help seal it so it doesn't dry out. To that end, I've sketched in a little space at the base of the tenon and the cap threads. I've also sketched in a flat lip I'll have to drill in at the lip of each interior thread, so it doesn't cut my O-ring.

You may notice that my threads are a little coarse for what's usually seen here: this is my first pen, so I'm trying to use the taps and dies I have on hand, without having to buy too many tools. So the only tap I'm buying for this is going to be the M7.5x0.5 tap, which I know I can get on Amazon for ~$10.

Thoughts are always appreciated, but mostly I want to show progress so I actually commit to finishing the pen.

-Hank


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[Displaced Canadian]

It's wise to start with what you have. Then when you decide to continue you have a better idea of what you really need to buy. Have a pad of paper handy for those "design changes" that will happen and notes for next time. don't be in a hurry, enjoy the process.

 

[Displaced Canadian]

Notes from my last pen.

 

[More4dan]

I would make up a few test joints from some scrap material to test your design to best place your o-rings, and size your o-ring grooves.

You might want to try to get the cap one in the cap so it doesn't show.


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[AdventiveIowa]

Dan,

That's a good idea, I'm looking at the cross section in Fusion 360 (I opened it up last night and reminded myself how aggravating it is to work with) and the gaps I have right now are not square, so I'm not sure how well the o rings will fit.

I'll try to make some practice fits.

-Hank

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[More4dan]

With a cap flush to the body, it's kinda of tight. I believe o ring are made to seal side to side, ID to OD with just interference. You might try a short section of flat on either side of the groove to get the best seal with minimum interference. I've done brass, aluminum and SS pens similar w/o o rings and didn't have issues unscrewing nor drying out. O ring would've necessary for eye dropper fill of the body.


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[Penultimate]

Greetings
Apple Rubber Products has a good design app for getting the right voice sizes.


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