When building picture frames, many customers call in and place orders for us to cut their moulding with mitered corners (aka chops). This means that all sides of the destined frame are cut at a 45 degree angle. When the sides are joined, 90 degree angles are formed to create four perfectly-squared corners for a picture frame. This information is nothing new with most of our readers, however, the following information could be something fresh to consider – were you aware there are actually four different ways to order chops, and that three out of the four ways could be considered “EXACT”?
Rabbet Size (with allowance)
Using the rabbet depth line as a destination point (plus a little allowance), this is where the artwork should hit with a little extra room. Allowing 1/8″ allowance is the standard, but you may want to clarify if you would like more or less of an allowance at the time of placing the order. We’ve heard of 1/16″ up to 1/4″ allowance – this all depends on each individual’s project.
Rabbet Size(EXACT – without allowance)
Using the rabbet depth line as a destination point, this is where the artwork should hit exactly – no allowance.
Outside Dimensions (EXACT)
Pretend the frame has already been put together, and the work of art has been placed inside the finished frame. This measurement takes into account the size of the artwork, plus the selected frame width. The requested measurements represent the size of the overall finished project – needless to say, using the projected outside perimeter of the frame as a guideline. Reasons may vary for ordering chops using outside dimensions (ie: this may be the inside portion of a frame combination or perhaps the designer is working backwards using measurements from a particular-sized space).
Sight Size (EXACT)
When using sight size measurements, the size requested is the size of the artwork image to be seen by the viewer, after the framing has been completed. This measurement uses the lip of the picture frame moulding as a guideline. The lip is not labeled on the diagram below, however it looks like the nose of the moulding (locate the line resembling the tip of the nose – right above the rabbet depth line, running vertically).