# Curved Surfaces on Fountain Pen



## comiris (Jan 9, 2013)

Hi Guys,

I want make a similar shape to the lamborghini FT. 

Metal lathe can do so much. Can I adapt a lathe for example to make a 4 axis?

What machine or tool do I need to create shapes like this for aluminium?

Input will be grateful!!


----------



## mredburn (Jan 9, 2013)

off center turning


----------



## mredburn (Jan 9, 2013)

Although you can mount a lathe on a mill, the motor usually is built for turning speeds not for stepper functionality.  I believe that there is one brand Tormach
Duality Lathe is the only one I have found that tries it


----------



## The Penguin (Jan 9, 2013)

research "therming"


----------



## BradG (Jan 10, 2013)

That really looks uncomfortable to hold


----------



## Robert111 (Jan 10, 2013)

BradG said:


> That really looks uncomfortable to hold



+1 Yeah, seems more a design exercise than usable pen.


----------



## Chuck Key (Jan 10, 2013)

BradG said:


> That really looks uncomfortable to hold



The first finger, middle finger and thumb seem to form a triangle when holding a pen.

http://www.penturners.org/forum/f14/cross-section-pen-photo-no-2-added-14917/index3.html


----------



## LagniappeRob (Jan 10, 2013)

I was wondering the same thing when seeing the off-center chuck in the PSI catalog. 
Then I found their youtube video of using it.
The Off Center Chuck System at Penn State Industries - YouTube

Check out starting at 2:15 for multi-sided.

BTW, they're being added to Amazon at a much lower price. Not in stock yet, but available to pre-order. Probably shouldn't do this since Amazon will change their prices on a whim, but here ya go:  PSI Woodworking CSC600 Off Center Wood Lathe Chuck System - Amazon.com


----------



## LagniappeRob (Jan 10, 2013)

Looking at the pen, I think it would be of more interest to Mazda RX-7 and RX-8 owners. It looks a lot like the rotors in our engines.


----------



## BradG (Jan 10, 2013)

Chuck Key said:


> BradG said:
> 
> 
> > That really looks uncomfortable to hold
> ...


 
Well i guess that depends on how you hold a pen. for me, that really wouldn't work


----------



## Joe S. (Jan 10, 2013)

My idea: get a large plywood disk mounted on the lathe, easily done with a faceplate. Drill a hole near the edge taking care to have it a square as possible. Make a closed end mandril out of a bolt or somthing and screw the pen part in. To add balance use some kind counter weight.

I've never done anything like this, but it might work with a little refinement.


----------



## comiris (Jan 10, 2013)

Chuck Key said:


> BradG said:
> 
> 
> > That really looks uncomfortable to hold
> ...



This is the same conclusion I came to but slimmer version. Under 10cm. 

I made some clay mock ups and it really does feel comfortable.

Few Papermates and especially Lami Safari FT (since 1980) incorporate this type of design.


----------



## NewLondon88 (Jan 10, 2013)

comiris said:


> Chuck Key said:
> 
> 
> > BradG said:
> ...



There's lots of pens using this design, and they are rather comfortable.
I usually snag one at the bank when i see them.. then I change the
refill. :tongue:


----------



## comiris (Jan 11, 2013)

Chuck Key do you have more pics of your cool lathe setup?

Ideally I want to repeat the process to exact tolerance. I was thinking also 3 axis cnc machining (may have to turn the aluminium rod 2-3 times by hand)


----------



## comiris (Jan 11, 2013)

comiris said:


> (may have to turn the aluminium rod 2-3 times by hand)



My hand is acting like the 4 axis, rotating for the 3 axis cnc.


----------



## Haynie (Jan 11, 2013)

Outside not so hard.  Inside of cap no idea


----------



## BradG (Jan 11, 2013)

Haynie said:


> Outside not so hard. Inside of cap no idea


 
good point.... any ideas anyone?


----------



## duncsuss (Jan 11, 2013)

BradG said:


> Haynie said:
> 
> 
> > Outside not so hard. Inside of cap no idea
> ...



Perhaps the "lost wood" technique?

Write up here


----------



## Dulos (Jan 11, 2013)

I know this is a lousy picture.  I took it with my IPad.   hopefully u can see I made a triangular pen on my lathe as a prototype a while back. The only way i could make it work was to make it a closed end pen.  It is now the pen I carry. It is quite comfortable to use. It is a long of process to make it work, but I think it could be a cool pen to make. If you want more info on how I did it, just let me know.

I do think the lost wood technique could work for the cap.


----------



## bigevilgrape (Jan 11, 2013)

Robert111 said:


> BradG said:
> 
> 
> > That really looks uncomfortable to hold
> ...



I'm not sure without holding it, but I get triangle shaped  wood pencils when I had to do a lot of proofs for math exams. I found the triangles to be much more comfortable then the standard wooden pencils.  I use the "standard" taught in school grip.


----------

