Home-brewed Acetal Pen

[Ravenbsp]

I made this pen from acetal rod stock, also known in DuPont land as Delrin. The bands and final are hand made from aluminum rod, the clip is a left-over from another kit, but seemed to go nicely with this pen.

I made this for an army officer who wanted a pen that would stand-up to just about anything, but not primarily metalic, because he said he would be likely to bend it. I don't even want to think about the abuse its going to get. I've used acetal in other apllications and its very tough, resilent material with a high breaking point. It doesn't really polish to a "glassy' finish, but in his opinion that would have been a negaive anyway.

It has a slimline transmision . The nib has a really nice tolerance. The the ball-point extends and retracts easily with no side-to-side movement when used. Sorry if I'm getting long winded, but it seemed like it took forever to make this one-off prototype and while I think it looks ok, I think that it is a little aesthetically lacking. At any rate, comments are welcome.

 

[Thumbs]

Nice Work! We've been told that you can't glue delrin. How is this all held together?[?]

 

[arjudy]

Nicely done.

 

[JimGo]

Very nice Bryan! Can we see some bigger pics? I'm anxious to see it all together.

Thanks for sharing!

 

[terrymiller]

looks nice is acetal an acrylic or type of metal.

 

[woodscavenger]

Can you give us a little more info on the nib/band section? Very nicely done BTW!

 

[Ravenbsp]

Thank you for your replies. Here is a larger picture, I've built a light tent, but am still doing a lot of trouble shooting.

Your'e right, delrin is pretty darn smoothe and inert stuff. But I found that by sanding the tubes and the inside of the blanks before using thick CA glue things held together quite well.

Delrin (acetal) is a sort of armor plating of the plastic family. I've used it in other apps and have succesfully run delrin tubes over with my car (and no, I'm not going to try this with this pen, though the before and after pix could be interesting...). The stuf machines very well, better than acrylics. It turns best with slow speeds and very sharp tools. Don't be aggressive with your tools, the stuff will more likely grab the tool from your hand before it will blow out the blank.

Here is a roough sketh of how I made the nib:

I used my metal working lathe to turn a small length of acetal to the same OD of the rest of the pen and then cut a tenon of about 0.25". I used various fractional, numbered or letter drill bits to achieve the indicated tolerances. The construct was then press-fit/glued into the bottom tube along with the aluminum band. The lower portion was then turned using traditional turning tools, a skew gouge I believe.

 

[Spike]

I like it. It has a tactile look. nice job.

 

[Rifleman1776]

Very interesting. I have worked a lot of Delrin and had the glueing problem mentioned. I wondered about that. It is bendable and armor tough, should hold up alright. Have you considered no tubes, just drilling the size of the tube ID?

 

[Ravenbsp]

I considered that, but there is just enough springiness int he material that I would worry about a tight enough fit, assuming I could get the machining tolerances right. I tried to dislodge the super-glued tubes and they hold steady. Even without the glue they are a pretty tight fit.

 

[Johnathan]

Great looking pen, I don't think it's lacking at all. Sometimes less is more! It looks like something from a great old black and white film, you could call it the Bogart![8D]