ensso Bolt Fountain Pen Review

ennso Bolt Fountain Pen Review

(Jeff Abbott is a regular contributor at The Pen Addict. You can find more from Jeff online at Draft Evolution and Twitter.)

The idea of a retractable fountain pen is something of a white whale. There are very few options, and it seems every one of these options comes with some serious trade-offs. For something that seems like such a big design challenge, that doesn't stop people from trying. It's also not often that we see new options come onto the scene in this category, so that's why I'm excited to talk about the Bolt from ensso.

On the outside, the Bolt looks like another machined metal pen that uses a simple bolt mechanism to control the retractable refill. The all titanium body is lightweight and feels great in the hand, but it's really surprising to extend the refill and see a slim fountain pen nib emerge from the end of the cone.

ennso Bolt Fountain Pen

At just 5.16 inches (13.2 cm), the Bolt is a really comfortable size both in hand and when storing. The barrel diameter is fairly slim at just 3/8" (9.5mm), similar to most gel pen barrels and a little slimmer than most fountain pens.

ennso Bolt Fountain Pen tip

In most cases, there are two Achilles heels when designing a retractable fountain pen: clip placement and sealing the nib when not in use. There are other challenges when designing a pen like this, but these two seem to be obvious factors with the products we have access to today. The way we hold a pen when writing is unique to each individual. For a pen like the Pilot Vanishing Point or Decimo, the clip placement might make the pen uncomfortable for many people. If you can't accommodate the clip being part of your grip pattern, then it just doesn't work for you.

ennso Bolt Fountain Pen twist

With the Bolt, the clip is an optional accessory that installs on the back of the pen barrel. The unit I have for testing didn't come with the clip, but it's easy to install by using a coin to remove the plain end and screw on the clip end. When using the clip to store the pen upright, this does face the nib toward the ground. I thought that might be an issue since gravity and motion might cause some ink to leak out and stain whatever it's clipped to.

I tried this out by simply carrying the pen around in a pocket with the point faced down. In my testing with normal walking, no ink escaped from the pen, and the nib was clean when I got it out to write. My assumption is that some leakage could still occur depending on the environment and the level of movement you put the pen through. I would certainly be careful about flying with this pen due to the large air pressure change. Either empty the pen before flying or isolate it in a bag to prevent some inky mishaps in your luggage. Overall, though, I really appreciate the clip placement on the Bolt, and I like the optional nature of the clip even more. Even though I don't have a clip to try out, I still think I prefer this pen sans clip. It's more sleek and the bolt mechanism acts as a great stopper to keep the pen from rolling around on flat surfaces when not in use.

Similarly, a fountain pen isn't much use if the tip dries out after a couple of hours while retracted due to a bad seal that lets too much moisture leave the nib and feed. This seems to be the really tricky bit to design and manufacture at scale. Pilot seems to have a good solution, as does Platinum.

ennso Bolt Fountain Pen tip

With the Bolt, I've been incredibly impressed by how well their seal design works. According to their webpage, they spent over a year developing and testing this system, and it's really simple in practice. It's just a small piece of silicone that has a couple of slits that form an X pattern that allow the nib to pass through, but come back together to form a seal over the nib when it's retracted. I've left this pen alone for over a month and come back to use it only to find that it writes almost immediately. Very nice. Also, ensso includes two extra silicone seals with the pen in case the original one (or second) fails. Time will tell how these hold up.

ennso Bolt Fountain Pen tip

One of the concerns I had when looking at this silicone sleeve mechanism is that the contact with the nib and the silicone might cause excessive ink creep on the nib. By ink creep, I mean how ink tends to leak a tiny bit around the slit on the top side of the nib. And if you try to use a paper towel to clean up a tiny dot of ink, you end up dragging a lot more ink onto the nib due to the capillary action of the towel when it hits the slit. I'm happy to report that this just isn't an issue with the Bolt. There hasn't been any ink creep on this nib at all.

ennso Bolt Fountain Pen disassembled

And while talking about the nib, let's just take a minute to admire this custom nib unit that ensso designed. It's reminiscent of the nib units you see in Pilot's offerings, but this one uses a standard international cartridge converter to supply ink. The actual nib and feed are super small — they're like miniatures.

I've really enjoyed using the Bolt over the past couple months. It's a solid performer that has really impressed me and removed any doubts I had about the performance of the retractable nib design. Operating the bolt mechanism is really easy to do one handed, and I really like the amount of resistance the spring provides. I also love how the nib retracts a bit slower than you expect due to the drag of the silicone on the nib unit. It's similar to watching a soft-close drawer finish closing. Satisfying.

ennso Bolt Fountain Pen comparison

The only nitpick I have for this pen is about the feel of the bolt mechanism. It works well, but I don't love the metal-on-metal feel/sound when operating it. This is likely unavoidable since all the parts are metal, but I wonder if a small synthetic bushing would help smooth out the feel and get rid of the minor nails-on-a-chalkboard sound of metal grinding against metal. Or maybe a little dab of carefully applied silicone grease would alleviate that problem. Either way, it's a minor gripe on an otherwise stellar pen.

ennso Bolt Fountain Pen converter

The Bolt is only available in the titanium finish, but you have an option of EF, F, or M nibs (and you can pick up several), along with the option of a clip. The clip is an additional $25 on top of the standard $120 price for the pen. You can pre-order the pen now and expect delivery later this month. If you like retractable fountain pens and like the aesthetic of this pen, you should go for it. It's a solid performer at a great price, and it will hold up to years of use thanks to the titanium material and the extra silicone seals that ensso provide with the pen.

(Brad purchased this pen via the enso Bolt Kickstarter campaign.)


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ennso Bolt Fountain Pen writing
Posted on April 2, 2025 and filed under Ensso, Fountain Pens, Pen Reviews.

Penedex, Your Digital Stationery Companion (Sponsor)

Penedex Pen and Ink Library

Our community is full of wonderful independent makers who turn acrylic rods into elegant, stunning fountain pens. Let me introduce a different kind of independent maker to the community: an app maker. Connor Rose is the independent iOS developer behind Penedex, your digital stationery companion.

Penedex was born out of his desire for a simple, elegant method of keeping track of his personal pen collection. From that idea grew a full-featured organizer and usage tracker for all kinds of pen addicts, whether you’re a student with a few pens in your bag, you have mountains of ink bottles in your closet, or if you’re a pen show fanatic. No matter who you are, Penedex is your modern digital stationery companion for all things pens, inks, and pen shows.

Penedex Pen & Ink Meta Data

With Penedex, you can catalog your pen and ink collection, prepare for a pen show, or check out what stationery stores are in your vicinity. You can add details to your pen and ink entries, such as nib type, pen material, ink color, shimmer, dry time, photos, and more. You can keep a daily log of your pen usage quickly and easily. Penedex will also keep track of how often you use your items and display a range of statistics about your usage. You can also add pens and inks to a wishlist to save for later, like when attending a pen show.

Penedex Show Calendar

If you’re visiting the Atlanta Pen Show this week it’s a great opportunity to try out the Pen Show Planner & Organizer. Add important events to your show checklist, or use the built in budget tracker to make sure your pen show haul won’t blow your budget.

Penedex International Map

Want to find stationery stores near the show? New for 2025 is the Stationery Store Map. Look for local stationers, print shops, or pen stores in your area and internationally.

Check out Penedex for iOS at penedex.com or on the iOS App Store by searching “penedex” or scan the QR code below. The app is free to download.

If you want to say hi you can find Penedex on Instagram @penedexapp or you can find Connor Rose at https://bento.me/connor-rose.

My thanks to Penedex for sponsoring The Pen Addict this week.

Posted on March 31, 2025 and filed under Featured Sponsor.