There are fixed blade belt knives, and there are jack knives/clasp knives. These come in a variety of shapes and sizes. Second hand will usually be less costly than new, and these second hand knives are well worth looking out for at your local second hand dealer.
A repro clasp knife.Clasp knives are generally not that costly even new from living history traders. If you are on a budget, stay away from custom made knives. If you are going to purchase a new or custom knife, make sure you do your research first as to style.
A repro clasp knife.Second hand butcher knives of the 18th century style are still available at dealers and markets. Stay away from stainless steel, only purchase carbon steel. Carbon steel is usually recognisable by it being a duller finish than the usually shiny look of stainless.
Two original butcher knives. One I found at a second hand dealer's, and the other I found at a local maket.Handles on 18th century knives were pinned, not riveted, but handles can be replaced where they have been riveted.
This too is an original blade, and I bought it without a handle.
This one I found second hand as is. I made the sheath. This is now my legging knife.
This was my Fathers craft knife, and that is what I use it for now. The blade shape could be changed on a knife like this.
An original Gully knife.
A Gully knife custom made for me by my close friend the late Geoff W. Howarth of Tamworth NSW Australia. 9 inches long closed.
Above: Pinned. A metal rod or nail is used and peened at both ends to secure it.
Above: These are brass rivets. Most if not all modern butcher knife handles are secured by rivets. As you can see they are much larger than the pins.