Is the threads pointy? Please reply
Hi Dinupravin... and Rudra, et al,
You really do not feel the threads on the Vac700 as much as you feel the sharp flange, (step-down), for the cap.
The Vac does have an amazing ink supply and it's fun to fill... mine also has a very smooth and nicely controlled wet nib and feed. But I do have to keep the valve open, (so the turning knob is never completely closed, leaving a gap); so if you're a perfectionist, or particular about aesthetics... like somebody I know and love...

...that could be an issue for you. For the time being, I'm trying to "get over it," because the pen is a GREAT writer with an awesome nib. The shape of the pen is a little unusual... and it's on the heavier side with the steel vac mechanism... it doesn't fit as comfortably in the hand as my 580 or 74 does, but it's not a deal breaker, either.
I've had no problems getting it in or out of my shirt pocket, despite it's flared turning knob... but I wear dress shirts... if your wearing a uniform, or have shirts with integral "pen pockets"; you might have issues.
Finally, while the Vac feels solid and well-made,... there is a certain, indescribable "clunkiness" to its material quality... I wish I could put my tactile experience into words... but I can't... "clunkiness" is as good as it gets.

Even though I also get the impression if you threw the Pilot and the TWSBI against a brick wall, the TWSBI would fare better.

Like I said... it's difficult to put into words.
The bottom line: If you can afford both pens, I'd get both pens... they both have their merits. But if I were on a budget and HAD to CHOOSE ONLY ONE... I think I would give the nod to the Pilot 74 equipped with the optional large capacity Con-70 converter.
It's a lighter pen... which helps when you're a student and you have those long writing jags... there's no sharp step... you get a solid gold nib... and you get a pen with respectable, conservative looks, (to me, demonstrator pens have a juvenile vibe going on), that will impress your professors into thinking you're someone who is mature and is to be taken seriously, (which is important when you're starting out... it's what helps you get ahead

)... and finally, the Pilot is a solid performer with a long, distinguished pedigree... so you know you'll be getting a pen with Lexus reliability.
HTH. Be well and enjoy life.
- Anthony
Edited to clarify text.
Edited by ParkerDuofold, 22 March 2019 - 00:25.