First off, I should have switched to scalpels long ago. For me, I find they have a far better feel than X-acto style hobby knives. The also never need tightening and seem sharper.

This sturdy case holds a standard No. 3 scalpel handle with a No. 11 blade. The hinged cap slides up and rotates away to allow the scalpel to easily slide out.

This is remixed from Nleinad's great case on Thinigverse. I removed the extra blade compartment to slim down the case a bit and it didn't fit the blade packs I have. The notch in the cap / lid was also removed, and two stops added to secure the cap when closed.

Requires an M3 x 10mm bolt and hex nut (nyloc is preferable).

To assemble, align the two parts and insert the M3 bolt from the cap side through the body. Add the nut and tighten enough to be secure, but loose enough to allow the cap to slide without too much effort. If you use a regular hex nut, add a drop of CA glue to inside of nut's end to prevent it from backing off.