Most costly kitless rollerball for me

[rixstix]

Prototype, work-in-progress on kitless rollerball with magnetic cap. Comments and/or suggestions welcome; especially if it prevents me from reinventing a wheel.

My wife said I shouldn't post this because it is a non perfect prototype, work in progress but I figured that there may be comment or suggestion that could help things along or possibly prevent me from reinventing the wheel. Right now, this is the most costly pen I've worked on when I add tools, blanks, parts & other rope, soap & dope used for the various number of experiments and tests.

The body & cap each have 8 neodymium magnets. Note to self drilling precision needs significant improvement. Note to self about individual magnets polarity. Note to self magnet set depth in holes. Backfilling magnet holes needs help. Magnets jump like fleas if you don't have them in the correct position and are impossible to find once they jump.

Cap thickness is determined by magnet length. I'm not a fan of the huge cap. The smaller magnets purchased were wrong polarity, so I proceeded using larger magnets. The smaller magnets will reduce cap diameter by a bit over 1mm.

I'm happy with the rollerball section. Section threads m9 x .75

Refill: Pilot V7-RT gel by special request.
Pair of smokey olive alumilite blanks from Exotic Blanks for the body & cap.
Short piece of Volkonskoite blank from McKenzie Penworks for rollerball section.
Overall length: 5 inches
Cap length: 2.125"
Cap Width: 0.56"
Body length: 3.25"
Body width: 0.5"
Section length: 1.44"

 

[magpens]

Well ..... first reaction is "Good for you ! ... And, thanks for showing !! ... It's both rare and also helpful to see a project at this stage. "

Now, please check your diameters .... Cap Width: 0.56" and Body width: 0.5" .... these don't seem to jibe with the pictures, IMHO.
The difference in the stated numbers is only 60 thou on the diameter, or 30 thou on the radius .... the pics suggest a bigger difference to me.

Thanks for providing the details you have given .... rather helpful for others ( including myself ) planning similar projects.

 

[sorcerertd]

That's a beautiful pen, but the oversized cap does kind of stick out like a sore thumb to me. The colors are great. Had to laugh at your "notes to self". Once those little suckers get stuck on something they are rough to get off, too. Especially if they aren't big enough to get a grip on.

I know nothing about kitless pens other than what I have seen and read here, but for what it's worth...
Neodymium magnets are really strong. Are you sure you really need 8 in each piece? Also, I assume they are shaped in such a way that they can't just be reversed? What about a metal band around the inside of the cap instead of magnets? The magnets in the body should be plenty strong enough to hold it in place.

 

[rixstix]

Now, please check your diameters .... Cap Width: 0.56" and Body width: 0.5" .... these don't seem to jibe with the pictures, IMHO.
The difference in the stated numbers is only 60 thou on the diameter, or 30 thou on the radius .... the pics suggest a bigger difference to me.

Cap diameter is 11/16" Darn those steel pocket scales when the caliper is outside.

 

[magpens]

Cap diameter is 11/16" Darn those steel pocket scales when the caliper is outside.

YES !! . That's more like it ! . . 11/16" = 0.69"

 

[rixstix]

Neodymium magnets are really strong. Are you sure you really need 8 in each piece? Also, I assume they are shaped in such a way that they can't just be reversed? What about a metal band around the inside of the cap instead of magnets? The magnets in the body should be plenty strong enough to hold it in place.

They're not very strong when you're talking 1.5mm diameter and 2mm long. I'm still working on a band but sourcing sizes that work has been problematic. Just found a couple of neo ring magnets that I think I can embed into the section at the middle step and use another ring in the cap.

 

[sorcerertd]

They're not very strong when you're talking 1.5mm diameter and 2mm long. I'm still working on a band but sourcing sizes that work has been problematic. Just found a couple of neo ring magnets that I think I can embed into the section at the middle step and use another ring in the cap.

Lord, I'd need a lot of magnification to work with those. Sounds like you have a plan b. I'll just watch and learn, then.

 

[magpens]

Regarding the magnets ..... just for comparison .....

.... a very similar design is the PSI Vertex Supreme ...... FP or RB pen with purely magnetic cap to body retention.

Of course, I do not know the "engineering" details of the design, but the magnetic attraction force is quite strong. . I've made these pens.

I believe the design consists of magnets on one side and steel band on the other but I could be wrong.

 

[magpens]

I'm still working on a band but sourcing sizes that work has been problematic. Just found a couple of neo ring magnets that I think I can embed into the section at the middle step and use another ring in the cap.

@rixstix
I am very interested in this concept. . . Hope you will continue to report the results of your "Research and Development". . Thanks.

 

[rixstix]

Regarding the magnets ..... just for comparison .....

.... a very similar design is the PSI Vertex Supreme ...... FP or RB pen with purely magnetic cap to body retention.

Of course, I do not know the "engineering" details of the design, but the magnetic attraction force is quite strong. . I've made these pens.

I believe the design consists of magnets on one side and steel band on the other but I could be wrong.

Yes, you are correct. I've deconstructed 2 Vertex Supreme for prototypes that worked out quite nicely. They do use magnet and chrome plated steel band. It's the chrome plated, rustproof steel band that is problematic for me. I am hoping the next magnet order will let me embed the magnet into the section and take the place of a Vertex Supreme steel band.

With the order today, I just crossed the 4 digit line with tools, parts, kits to deconstruct, blanks and more rope, soap and dope. Someone around here might get a bit grumpy pretty soon.

 

[magpens]

Yes, you are correct. I've deconstructed 2 Vertex Supreme for prototypes that worked out quite nicely. They do use magnet and chrome plated steel band. It's the chrome plated, rustproof steel band that is problematic for me. I am hoping the next magnet order will let me embed the magnet into the section and take the place of a Vertex Supreme steel band.

With the order today, I just crossed the 4 digit line with tools, parts, kits to deconstruct, blanks and more rope, soap and dope. Someone around here might get a bit grumpy pretty soon.

@rixstix

Are you serious ?? . . . 4 digits ?? . . . Are you building a house in Couer d'Alene ??

But if you get into trouble . . . just say (quietly) you know a guy (not me) who is up past 5 digits for the last decade or so !! ...... BUT ... Shhhhhhhh !!!
It just might work to help bale you out !!!

 

[rixstix]

I had a lot of "specialty tools", dies, taps, drill bits, full set of ER32, and so on that I just had to have to make things easier or maybe just in case.. Nickels and dimes add up very quickly. You know, blanks aren't cheap. Nor are pen kits that just get deconstructed for parts. I have tentative permission for a new lathe if I sell 3 of the 5 that are in service right now.

Can't build a house here right now due to labor and material shortage.... IF you have dirt to build it on.

 

[Aurelius]

They're not very strong when you're talking 1.5mm diameter and 2mm long. I'm still working on a band but sourcing sizes that work has been problematic. Just found a couple of neo ring magnets that I think I can embed into the section at the middle step and use another ring in the cap.

I would suggest against ring magnets. They are usually polarized with a single pole inside and a single pole outside. You won't get a lot of pull from a configuration like that. If you already have a way to embed the small disk magnets into the body, your best bet woud be to put small magnetic steel pieces opposite the magnets in the cap. The reason you want individual pieces is that way you will fully magnetize the steel and get the strongest hold. If the field has to come back through a solid ring of metal, it creates small regions that are aligned the opposite way.

 

[rixstix]

I would suggest against ring magnets. They are usually polarized with a single pole inside and a single pole outside. You won't get a lot of pull from a configuration like that. If you already have a way to embed the small disk magnets into the body, your best bet woud be to put small magnetic steel pieces opposite the magnets in the cap. The reason you want individual pieces is that way you will fully magnetize the steel and get the strongest hold. If the field has to come back through a solid ring of metal, it creates small regions that are aligned the opposite way.

The next version will have the 8 body cylinder magnets alternating polarities in order to keep them from jumping out of their holes before they can be glued. RE ring/tube magnets: I have options for field to be polarized across the diameter of the ring/tube or in line with the length of the ring/tube.

DUH moment here when I read your comment about the small steel pieces. Drill rod will fit that description nicely. TNX

 

[Displaced Canadian]

Good drill bits are worth what you pay for them. Getting the cap smaller and closer to the size of the body will help the look. I like the look of the front section. A more solid color might not look as transparent. What you are trying to do isn't a simple thing. I would say so far so good.