If you are fortunate to own a piece of furniture with this type of drawer joint you are in luck. This easily dates your piece to between 1870 – 1900. This method of drawer joint was invented by Mr. Charles Knapp of Wisconsin and he patented the first joint making machine in 1867. The example shown in this photo is a drawer in a Victorian Eastlake dresser – owned by none other than my husband. He forbade me to sell it.
