Diamond Knurl Rollerball with matching Center Band and Finial

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KMCloonan

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Jun 13, 2017
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Like @sorcerertd (Todd), I have been experimenting with Custom Finials (thanks to John Underhill) and custom center bands, as I have been inspired by several that were posted to this forum.

Todd also mentioned it would be nice to see how others make their center bands. I searched the IAP library, and unless I stink at searching, I could not find much info on the topic (there were a couple on custom finials, but not center bands).

I watched a couple you-tube videos on ring making, figuring it could translate to center bands... And landed with the process below, which can use a lot of improvement, but it was a place to start. Any suggestions/Ideas, etc are welcome.

Here is the original Center band from the Diamond Knurl Rollerball:
Original Center Band.jpg

The ID of the center band is about 0.468", which is basically 15/32. I used a 15/32" drill bit to drill a hole in a scrap of the same blank I used on the pen. The width/Thickness of the center band is about 0.158". I used my bandsaw to cut a 0.160" wafer off of the scrap blank, and I sanded it to the proper thickness.

Ring blank 2.jpg Ring blank.jpg

Then I had to figure out how to turn it. I started with a punch from my punch set as a mandrel, but I could not get a tight fit with the ring blank. I decided to turn my own mandrel out of a spare resin blank to the approximate diameter, with a taper so I can press it on.

Mandrel2.jpg

I then used some hot glue to hold the ring blank in place (I saw others use tape on the mandrel to make a tight fit - that could also work). I used a live center to support the mandrel, as it was a bit wobbly without that.

Mandrel.jpg

I turned the blank down to the final diameter (with a lot of checking with calipers). I then used micromesh to polish it on the mandrel, and then installed it on the pen.
002.JPG 005.JPG 007.JPG

The finial I made was a little thicker than I had planned, but it looks ok, and I did not want to start over. ;)
 
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JohnU

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Jan 31, 2008
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Ottawa, Illinois
That looks great Kevin! Congrats!!!
I like how you made the tapered mandrel for the center band. When I make them, I turn the outer diameter first from a scrap solid piece glued to a wood piece, similar to how I make the finial, then I use a small scraper I made from grinding down a very small screwdriver, and turn the inner diameter and part it off after I polish it. I buff it by putting it on a tapered insertion tool I use when I epoxy tubes in blanks. Your way seems to work just fine, just thought I'd share to give you some ideas. Keep up the great work!!!
 

KMCloonan

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Jun 13, 2017
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Location
Round Lake, Illinois
I was watching some YouTube videos on ring making, and I saw a way to improve my cheapo center-band mandrel, based on the ring maker mandrels.

I cut two kerfs in my mandrel, 90 degrees apart. Now, when I slip a center band blank on the mandrel, and snug up the tail stock live center, the cone tip on the live center expands the mandrel, creating pressure on the center band ring, holding it securely in place. Pretty simple, but it seems to work ok.

A.JPG D.JPG B.JPG C.JPG
 
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