What kind of sheath is this?

[dougfergy]

Has anyone here ever done one similar and if so, can you share any secrets?  Is there some trick to fitting it together?  I'm thinking about this type sheath for a large Bowie I just about finished and the blade alone is 10 inches long.  With that length blade I'm thinking I will have some kind of time fitting the sheath part through the slot in the back piece.  I'm just kind of bumfuzzled.  I can't find any videos on building one and only a rare photo here and there.  Instead of risking copyright infringement, I drew up a sketch of what I'm talking about.  Don't judge me!  I'm not an artist!

 

[fredk]

Its essentially the same as a Mexican Loop pistol holster.

Wet the rear piece which forms the belt loop and it should be flexible enough to stretch and fit the sheath down thru. When it dries it'll stiffen and shrink a bit to hold the sheath tight in place