This is a list of pen and refill hacks that I know of. If there are any that you are aware of that are not listed feel free to let me know. Most will require a spacer to fill in the backspace. I use plastic tubing that I’ve gotten with some of my Karas Kustoms pens, but the extra plastic on the back of a standard ballpoint refill (like a Bic Stic) will work just as good and the length of the spacer will vary depending on the refill, just measure enough to lengthen the non-stock refill to the stock refill. I’ve included some pictures to give an idea of the lengths of the spacers needed for the Lamy rollerball pens.
The Schmidt P8126/P8127, any Pilot G2 sizes, Pilot FriXion, Uni-Ball Signo 207, Uni-Ball Jetstream, Zebra Sarasa Clip, Pentel OH! Gel, and Pentel EnerGel refills will work, though a spacer will be required. The Signo 207 and Jetstream tip will extend a little farther out than the others but shouldn’t affect how it writes. If this bothers you, just trim a little bit of plastic off the back of the refill. Mont Blanc rollerball and FineLiner refills will work with a small spacer. The tip of the Mont Blanc refills won’t stick out as far as some other refills, and I think this is due to the threading on the Mont Blanc refills, but this shouldn’t affect the usability of the refills. Pilot Precise V5/V7 RT, and Pilot V-Ball RT (Pilot Greenball) refills with a spacer should also work though I haven’t tried them. (Pilot FriXion and Uni-Ball Jetstream hacks submitted by Michael Green)
Any Pilot G2 size, Pilot FriXion, Uni-Ball Signo 207, Uni-Ball Jetstream, Zebra Sarasa Clip, Pentel OH! Gel, and Pentel EnerGel refills will work with a spacer. The Signo 207 and Jetstream tip will extend a little farther out than the others but shouldn’t affect how it writes. If this bothers you, just trim a little bit of plastic off the back of the refill. Mont Blanc rollerball and FineLiner refills will work with a small spacer. The tip of the Mont Blanc refills won’t stick out as far as some other refills, and I think this is due to the threading on the Mont Blanc refills, but this shouldn’t affect the usability of the refills. Pilot Precise V5/V7 RT, and Pilot V-Ball RT (Pilot Greenball) refills with a spacer should also work though I haven’t tried them. The Schmidt P8126/8127 refills will NOT fit. The P8126 refill is wider than the stock refill and the tip won’t come through the nose cone of the pen. I think the P8126 hits the metal tension ring inside the barrel and that this is what stops it. (Pilot FriXion and Uni-Ball Jetstream hacks submitted by Michael Green)
The Schmidt P8126/P8127, any Pilot G2 sizes, Pilot FriXion, Uni-Ball Signo 207, Uni-Ball Jetstream, Zebra Sarasa Clip, Pentel OH! Gel, and Pentel EnerGel refills will work, though a spacer will be required. The Signo 207 and Jetstream tip will extend a little farther out than the others but shouldn’t affect how it writes. If this bothers you, just trim a little bit of plastic off the back of the refill. Mont Blanc rollerball and FineLiner refills will work with a small spacer. The tip of the Mont Blanc refills won’t stick out as far as some other refills, and I think this is due to the threading on the Mont Blanc refills, but this shouldn’t affect the usability of the refills. Pilot Precise V5/V7 RT, and Pilot V-Ball RT (Pilot Greenball) refills with a spacer should also work though I haven’t tried them. (Pilot FriXion and Uni-Ball Jetstream hacks submitted by Michael Green)
Any Pilot G2 size, Pilot FriXion, Pilot V-Ball RT (Pilot Greenball), Uni-Ball Signo 207, Uni-Ball Jetstream, Zebra Sarasa Clip, Pentel OH! Gel, and Pentel EnerGel, refills will work with a spacer. The Jetstream refill will need to be trimmed some in order for the nock to lock in place. Mont Blanc refills, and Pilot Precise V5/V7 RT refills with a spacer should also work though I haven’t tried them. I don’t own a Tipo so at this point I’m not sure if the Schmidt P8126/P8127 refills will work or not. (Submitted by Michael Green)
The Uni-Ball Signo DX (UM-151) refill will fit, it just needs to be trimmed to the same length as the Pilot Hi-Tec-C. This hack is for the regular Render K, not the Render K G2 model. The Uni-Ball Jetstream refill can be hacked to fit the regular Render K. To do this, the collar on the Jetstream refill needs to be sanded down to fit into the Render K body and a spacer will be needed to fill in the backspace. Cutting the collar can achieve the same result as sanding it down but for some reason cutting the collar off seems to affect how the refill writes so it is better to sand it down. (Jetstream hack submitted by Aaron Stanley)
The Uni-Ball Signo 207, and Pentel Energel refills will fit. The tip on the Signo 207 will extend a little further than the tip of the Pilot G2 tip but shouldn’t affect how it writes. If this bothers you, just trim a little bit of plastic off the back of the refill. The EngerGel refill fits a little more snugly in the body of the Render K G2 so you may have to twist the refill a little bit as you insert it into the body of the Render K G2 but it will fit. The tip may extend a little further as well, but again shouldn’t affect how it writes.
The Uni-Ball Signo 207, Pentel Energel, Zebra Saras Clip, and Pilot Precise V5/V7 RT refills will fit. There are a couple of different ways to get the refills to fit. All of these refills have a large hole at the back of the refill instead of a plug (the Precise V5/V7 RT has a plug but it’s shaped differently than the G2 plug so it has the same issues as the other refills listed.) which causes the clicky mechanism to go into the hole and not extend the refill. One way to solve this problem is to fill in the hole with glue, a plug from a Pilot G2, pieces of tape, etc. all of which can still cause issues getting the refill to extend. The simple solution is to trim the aforementioned refills to the length of a Parker Ballpoint style refill and use the black plastic spacer that Karas Customs includes for use with Parker Ballpoint style refills. (You still use the spring for the Pilot G2 refill.) (Hacks submitted by various people but I can’t remember the names, sorry.)
Yes, the lowly Bic Clic can be hacked with a better refill, in this case the Pilot Hi-Tec-C Slim Knock refill. The Hi-Tec-C Slim Knock refill is shorter than the Bic Clic refill so a spacer will be needed to fill in the backspace and the tubing of the Bic Clic refill is perfect for this. Simply cut enough tubing to lengthen the Slim Knock refill and tape the two pieces together. Due to the clicky action of the pen, taping the two pieces together ensures everything works as it should. (Submitted by Chase Nordengren)
This isn’t a refill hack per se, but more of hacking two pens, the Karas Kustom Retrakt and Karas Kustoms Bolt, together. I believe I first saw this on Instagram but can’t remember. There are a few simple steps to make a ReBolt and the guys over at Nock Co have done a blog post on it, so instead of posting everything here, I’m simply going to link to their post.
The Pentel EnerGel refill will fit the TechLiner. Simply trim the collar on the refill a small bit so the magnet seats fully onto the refill. (Submitted by Jeffrey Bruckwicki) The Uni-Ball Jetstream will fit without any modification but I have heard of ink flow problems attributed to the magnet not playing nicely with the hybrid ink. (I’ve seen a few people mention this hack but the only person I can think of now is Ian Hedley so sorry to those of you whose name I can’t remember)
The Uni-Ball Signo 207, Uni-Ball Jetstream, Pilot G2, and Pentel EnerGel refills will fit. Simply trim them to the same length as the Schmidt P8126/8127 refills. (Pentel EnerGel hacked borrowed from Mike Rohde. Other hacks submitted by various people but I can’t remember the names, sorry.)
There are a couple of different hacks that I am aware for the Fisher Space Pen. Both hacks were done with the Fisher Bullet but I don’t see a reason why they wouldn’t work with the entire line of Fisher pens. The first hack uses the Uni-ball Style Fit refill. Ana at The Well-Appointed Desk did a post about this hack so I’m going to link to her postThe other hack uses the Pilot Hi-Tec-C Slim Knock refill. For this hack, you leave the Fisher spring in place, add the Slim Knock spring into the barrel (yes, two springs) and toss the Hi Tec C Slim Knock refill in and you’re done. If you notice any wiggling of the tip when writing, you can add some washi or scotch tape to the end of the refill just above the tip. (Pilot Hi-Tec-C Slim Knock hack and photos submitted by Aaron Stanley)
TOP: Lamy M66 BOTTOM: Modified Schmidt 8126
RED ARROW: the Schmidt refill was modified by cutting down the ferrule of the point as shown. The remaining “flange” is about the same thickness as the Lamy cartridge. A razor knife or razor blade works well with patience.
BLUE ARROW: the end caps have been switched. The Schmidt refill now holds the Lamy’s original cap. A small pair of needle nose pliers removes the caps easily. I did not put a micrometer to them, but they seemingly fit perfectly.
GREEN ARROW: That adapter is made from the shipping protective cover/seal that comes on each Schmidt 8126. Cut off approximately 4mm and slip it over the Lamy end cap.
The outer edge of the end of the gray plastic adapter (furthest from the tip of the cartridge) needs to be chamfered (the edge rounded off) to work properly and some minor sanding need to be done the get the correct length for the adapter. Too short and the tip does not protrude past the nose of the pen enough, and if too long the cartridge will not lock in the extended position.