The early coffins were generally made by the local cabinet maker or carriage maker.
The coffin takes on the "shape" of the human body. The first part to be made was the bottom and was measured to fit the feet of the deceased. From there, it widens to accommodate the hips, then wider still to accommodate the shoulders. Then the coffin narrows to fit the head.
This way, when the viewing was finished, if the ground was frozen, and the body needed to be kept in the barn or shed for the winter, it was stood on end and the shape of the coffin ensured that the person did not collapse inside while waiting for the ground to be thawed enough to allow burial.
The inside of the coffin was painted with pine tar, a sticky substance from the pine tree which has a pungent pine odour. The smell stopped the smell of decomposition from taking over the house. As well, the tar was a natural preservative that slowed the decomposition of both the body and the wood. Pine tar was often used in medicines and stopped the spread of any diseases that the body may have been carrying (like cholera, small pox and typhus).
The door of the coffin was sealed shut with pine pitch. This is a thinner pine material, which looks like sap and is very gummy. It is a fairly strong adhesive. This, too, prevented any diseases from being “leaked” from the casket should the body need to sit for a time before being buried. It was also helpful for keeping the coffin closed on long, bumpy wagon rides to alternate villages for burial.