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EAB (Exchange-A-Blade) Folding Utility Knife

by PvtDBJackson Jan 27, 2016
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Love it. I own several of the Gerber ones I give them out as gifts regularly but I can never find them for sale anymore. Going to print a few out. =]

This thing is awesome! Absolutely love it. Well done!

It is one of the simplest utility knife yet a brilliant design! It works and function perfectly, and I use it for pretty much every thing. Thank you so much....

Love the design, works great first try, my one complaint is how loosely the blade fits into the slot, this could cause some issues with fine detail work with the blade wobbling around like that.

The design, attention to detail is amazing. You really thought through the aspects of 3D printing. How you got the set into the liner-lock/frame-lock spring-tab was incredible.

And I have to say it's probably the single most actually useful 3D print I've ever produced. I love the Gerber EAB, but with one downside, I always lose them! Now I can just print another and another and another.

this design is EXCELENT !!! thanks !

When I printed mine, the hinge the it folds upon was completely merged solid and I was unable to free it to a working hinge. In the process of me trying to free the hinge I snapped the entire thing in half. any ideas on how I can get it to print better?

Any chance on adding a pocket clip to this?

Thanks, great work!

Hi! Would you be able to upload the Solidworks file and .step for this design??? I'd like to play with putting my name onto the side :-)

Awesome! Thanks and have a great day!

Excellent design. It printed perfectly. I wanted to make a thumb push that is held in place by the blade screw. This would make it easier to open one-handed.

Nice work! I ought to print some of these and just leave one on every worktable/desk in my apartment... Because it seems like whenever I want to do something simple like open a box, my real Gerber EAB mysteriously disappears! lol ;D

God I love my EAB... Maybe I should just bite the bullet and get 2-3 more real ones since they're so cheap!

Keep up the good work, functional/useful designs are the lifeblood of 3D printing! :)

I really enjoyed this design and I have been using it for a few days now at work. It is holding up very well and washes off easy. I printed mine in PETG and it came out great. Thank you for the excellent model.

It looks like a person's index finger would be directly below the blade. Have you tested this for strength and safety?

Actually, testing it to the breaking point is probably a very dangerous thing to do because if and when this print splits open.. well..
Might be best to do it with a chain mail glove, but even that might be a bad idea.

Made one in PLA and have been using it all week at work with no issues. The safety 'clip' has gotten loose (still works), so I am making a new one, but other than that it seems pretty safe for light/medium duty and now have to make one for everyone on my team! :)

I have tested it for strength. It has held up remarkably well printed in ABS at a high temperature for maximum layer adhesion. The index finger does sit below the blade, however the finger groove keeps it there and there is more than sufficient material there for safety. I have been carrying and using mine every day for the past few weeks with no signs of degradation. However, as the blade is simply a utility razor blade, I do not put it through abuse that one might subject a true knife to. The design is sufficient as a box cutter, light duty knife, or working with light duty dry wall, etc. Basically, anything you might use one of these knives for: https://upload.wikimedia.org/wikipedia/commons/thumb/c/cf/Box-cutter.jpg/1280px-Box-cutter.jpg this knife will handle, and then some. This just offers it in a convenient folding package.

Thank you for your concern. As with any knife, it is up to the user to be safe.

cool.. I appreciate your design work, and wouldn't want to minimize that. I like it a lot.

The potential safety issue kinda grabbed me. I've snapped blades and broken knives while hanging rock and was glad the knifes were made of steel.

Prints are layered, and thus they easily split apart. The box cutter in the photo was injection molded and is far stronger in every dimension. I second your motion that it's up to the user to use his head, and be safe.

If you look closely at the model and the printed example, it's designed to be printed so that the layers are perpendicular to the blade. Also, when cutting, the force is pushing the blade away from your finger. the only way the 'guard' part between your index finger and the blade could contact the blade, is if you intentionally started putting a lot of force on that guard piece, it's not something that can happen in normal operation.

But yeah, if someone decided to print this on its side, then the layers would be parallel to the blade and you'd have a really bad day...assuming you even got that far without something else breaking... Standing it on its back like that definitely seems like the optimal orientation for printability as well as strength. :D

look.... I don't wanna criticize this thing. I like the design work.

I am intimately familiar with the strengths and weaknesses of plastic. My own projects focus on useful objects and tools. Printed plastic is either appropriate for the project, or it is rejected. I have designed many semi-dangerous but useful things and did not publish them. I designed one with a ceramic blade, and it had no metal at all. (btw kiddies, those ceramic blades are "doped" with something that will set off a metal detector.)

How strong is the locking mechanism? If by twisting the knife, and the front spreads apart a millimeter or two, won't the two little bumps lose their grip and the whole front blade assembly just flies out? I get a tingle down my spine when I imagine actually using this knife.

However, I do like the folding idea. Just that rather than a blade, something else needs to be up front.

The blade assembly cannot be removed from the base of the knife. The front cannot spread apart under twisting since the blade assembly is held in place via a bridged axle that is printed in place. I have added a cross-section view to show the mechanism. The entire knife assembly must be printed as one piece at the same time, it cannot be assembled or disassembled. The lock mechanism is surprisingly strong, and as you apply force to close the blade, it is designed so that the liner lock is driven further into its locking position.

I have still been carrying and using my original knife that I printed back in January with no degradation or failures.

Your built-in support was a pain to remove. I had to press hard with an Exacto and had to be careful. So, using Blender, I removed your 2 support blocks, and let my printer software (Afinia) generate it automatically. Afinia has pretty good support structure routines. It is (usually) very easy to remove.

As I hoped, support on this second print was thin, fragile and was off in a few seconds.
The axle parts were free to move on both prints. Whatever clearances you set worked very well.

The knife is great considering the limits set by the material, process and the design. I wouldn't know how to improve on it.

If I was forced to print an actual work knife, the design wouldn't fold, would have real thick sections, and it would be ugly as sin... but also stronger, and hopefully somewhat safer to use.

The spring keeps the knife open, but doesn't really keep the blade closed. I would not carry this knife in my pocket or hang it on a belt, so I'd nix the belt clip.

Beyond that I am very impressed with the design work. This knife file is the best I've seen among anything I've downloaded from TV, and that I've played around with, and examined to any degree. Everything is straight and square with the world... I sense a professional touch.

axle. My bad for not examining it more closely.
I'm printing one now, and will give it a proper evaluation.
ABS, 0.2mm layers, fine quality.