Never ship a knife with an exposed blade. This is very dangerous to those folks who work in the shipping services and may result in your package being confiscated and you being fined.
If it is a folding knife, and can be closed, fold all blades closed.
If it is a fixed blade with a sheath, you may consider shipping it in the sheath, if the sheath is solid.
If it is a fixed blade without a sheath, or you prefer to not ship the sheath, create a cardboard cover for the blade.
Take a piece of corrugated cardboard (the type shipping boxes are made from). Fold it in half and place the blade’s edge in the crease of the fold. Mark the length one inch past the tip of the blade.
Set the knife aside.
Unfold the piece of cardboard and trim it to length and to a width that is slightly over twice the width of the widest part of the blade. Re-fold along the crease and tape the other side together.
You should now have a cardboard “sheath” that will cover the blade. Very carefully slide the blade into this cardboard cover, with the edge along the fold in the cardboard.
Wrap the closed folding knife, knife with sheath or knife with the cover in bubble wrap or packing paper, taping it together.
Place this bundle in a sturdy box, with plenty of packing material around it so it does not shift during shipping. Once the box is closed, you should be able to shake the box, and your packaged knife should not shift or move abut in the box.
Note that I have been using the word box; I strongly suggest you do not ship your knife packaged in a envelope or bag, or anything that is flexible. If you want to put it in an envelope and then put the envelope in a box, that is fine. The box you use should be solid and of sturdy material (think corrugated cardboard used for most shipping boxes…), not be torn or of flimsy materials (like the material cereal or cracker boxes are made of). The only other type of packaging I can recommend considering are rigid tubes, like those that carpet comes rolled in. If you use a rigid tube, make sure to fabricate a solid end cap for each end, of wood or solid cardboard, and tape it on well.
Think about it this way: you are shipping something of value, maybe only to you, but that is important. Maybe it is a family heirloom, irreplaceable. It may be somewhat fragile. And you certainly don’t want it to poke out of your package in transit. It’s trip may include some bumps, drops or even some knocks; don’t you want to take the time needed to package it so there is the least possibility of damage to your tool, or that your package could come apart during shipping and all that shows up is the empty packaging alone…
So go the extra mile to pack it well, and safely.
It helps to include in the box a print-out of the portion of our correspondence that discusses the work we agreed on.
Also, please make sure to include your actual shipping address, in the box, or in an email, where you would like the knife returned to. If not, I will have to request an address confirmation, which will delay the return shipping of your knife.
Tape the box up well, using solid well made packing tape, covering any open seams, folds or flaps. I suggest avoiding duct-type or electrical tape, as it can get messy and sticky in transit.
Consider not writing anything on the box that states or implies there is a knife in the package. For example, abbreviate my business name to S&SK. This can help deter theft.
I suggest you ship your package with insurance, via the carrier of your preference.
If you choose to ship with certified, or signature on delivery, it will greatly complicate the delivery of your knife. I live out in the country, and am rarely home when the postal service delivers (to my secured postal box). So after they leave a note, I have find a day, and time, when they are open, then drive into town, and wait in line, often for a good bit, to get your package. And none of that is really necessary. If you really prefer to ship that way, please confirm with me first.