Hello, this is Fountain Pen Researcher (Eureka admin).
Today, I completed the slim asymmetrical prototype.
After completing the prototype, currently actual use test is taking place.
After some inial testing, I immediately found some problems that needs improvement.
1) When I first tried to fill the ink,
the ink did not fill in so well, so I learned that it can only be filled with a syringe (efficiently).
The thin needle injects the ink thinly, so it goes in well.
eye dropper injected thick ink, so there was a problem with the surface tension, which hampered proper ink filling.
2) The cap must have a perfect seal.
In the first attempt, the cap did not seal well, so when I filled the ink from the back, a lot of ink came out inside the cap.
If the cap is perfectly sealed, even if you open the back cap and inject ink, ink flow to the nib is almost stopped.
If ink flows out from the back to the nib, an equal amount of air must be displaced.
If the cap is airtight, the ink cannot flow out.
3) The more precise the tolerance of the sealed part is, the better.
I realized that I need to be even more strict with tolerance management than with typical models.
The current goal is to keep the tolerance of the main sealing parts within 0.03mm.
If possible, I want to aim for almost zero tolerance...
4) Since the cap seal is very important, I plan to change the current single seal to dual.
Also, I think I need to increase the screw tightening length.
I plan to develop two types of caps: plain and faceted.
In the case of the faceted type, the part where the cap ends is very tricky.
I will try to improve that.
This project seemed to be an easy one, but it is much more difficult than the other models.
But since I started it, I will try to perfect it and upload the finished product.
Thank you.
The photo below is a prototype that has not been polished.
