This blade isn't like the others in their line up. To remove blade Screw off the handle portion. It should be broken down into two pieces now.

Now holding the dull side of the blade (make sure to hold it with a piece of leather or material the blade won't cut through to protect yourself) twist the collar assembly and blade in opposite directions (may have to use some elbow grease. I had to twist kinda hard for mine).

The collar should slide off and blade should come out. You can now slide old blade out and replace it

Assemble it back together (No need to twist the collar again just replace the blade, slide collar back on and hold everything in place as you twist the collar/blade and handle together. Make sure it's tight.)

I assume since I do leather work meaning lots of repeated cutting through thick leather it made my blade a little harder to remove.

Also I would suggest fiskars #2 blade instead of X Acto. For my purposes they are a bit more durable and sharper but your results may vary.

Excellent quality knife but the "safety" cap is loose and doesn't stay on. Plan on buying a separate safety cap or improvising your own.

My daughter is working on school project. She has to make a diorama. She decided that it needed to be bigger than a shoebox size so we had to take a bigger cardboard box and cut it down to size. Then we had to cover it with paper and cut out windows and a door and make other cuts. I really was not sure how we were going to go about doing this. I made some of the bigger cuts with a knife and that was okay but I knew that to make the cuts to the windows and the doors we were going to need something that worked better.

Then I remembered that when I was younger my brother made some models out of balsam wood and he used an x-acto knife to do the cuts. When I was researching different options I saw that there was a number 1 blade and a number 2 blade. I opted for this one, the number 2 blade because I wanted something a bit more heavy duty to handle the cardboard (which was, in a couple of places, double thick due to how he box was constructed).

The x-acto knife is very sharp - too sharp for my daughter to do these cuts herself - so I had to do it. It worked great! Nice clean precision lines that cut through everything.

My only complaint is that when trying to cut through some very thick parts the blade kept falling out. Once it got stuck in the cardboard itself and a couple times it just fell out and fell to the side. I was able to pick it up and put it back in but even though I was trying to tighten the blade in as much as possible it kept happening. I think it is because the blade was no longer as sharp at that point and/ or because I was trying to cut through something so thick that it was at the limit of what the blade could handle. In either event, after I got the blade in I was able to keep going. And, when I tried to cut through something thinner after that it did not fall out again.

The blade comes with a cap which I think is extremely important. No one wants to stick their hands in a drawer and get stabbed or cut with something as sharp as this. It is essentially a razor blade with a handle!

All in all, if you have a project and you need to cut through cardboard, paper, fabric, and other products like that and you want to have precision cuts then this is for you.

Works well and the thicker handle is much nicer.

Plan to use it to remove a fractured protective cover on my iPhone.