2019-11-2

In this post we explore the steps and calculations needed to create a custom frame

Tape Measure

Calculator

Calipers (tape measure is also adequate)

Taking Measurements

The first step is to grab the measurements of the source material. In this case we are creating two frames, which measure:

8"x10", 1" margin

24"x36", 3/4" margin

Calculating Frame Size

The rough frame design we're going to be making today are shown below:

Diagram showing an overview of frame dimensions Diagram showing a cross section of moulding terms

Moulding - The physical structure of the frame

- The physical structure of the frame Frame/Artwork Size - The maximum size of paper that will fit inside the frame

- The maximum size of paper that will fit inside the frame Window/Mat Size - The viewable area of the artwork

- The viewable area of the artwork Moulding Width - The total width of a side of the frame

- The total width of a side of the frame Rabbet - An inset portion of the frame that layers fit into

- An inset portion of the frame that layers fit into Rabbet Lip - The portion of the moulding that the artwork seats into

- The portion of the moulding that the artwork seats into Rabbet Depth - The capacity of the frame to contain layers of backing and glass and artwork

Citations from victorian frame company and frame destination

To figure out all how big everything needs to be follow these steps:

1 - Frame Size

The frame size is the maximum sized artwork that will fit inbetween the rabbets. A larger frame can be used with a mat.

Standard frame sizes (in inches) are:

5x7 - Photographic print size

- Photographic print size 8x10 - Common artwork size, commonly used with a mat to frame a 5x7 photo

- Common artwork size, commonly used with a mat to frame a 5x7 photo 8.5x11 - Standard US paper size frequently used to frame certificates

- Standard US paper size frequently used to frame certificates 11x14 - Commonly used to frame a 8x10 prints with a mat

- Commonly used to frame a 8x10 prints with a mat 16x20 - Larger frame for paintings or a centerpiece of a wall

- Larger frame for paintings or a centerpiece of a wall 20x24 - Large frame

- Large frame 24x36 - Standard poster size

Researched from picture salon and frame usa

2 - Choosing a Window/Rabbet Lip

The window is the visible portion inside of the frame. Usually it is 1/2" smaller than the frame size, allowing for a 1/4" lip.

3 - Moulding Width

There are fewer standards regarding the width of the moulding surrounding the picture, this is based on aesthetic and what tools and materials are available. In this case based on available material a 2" moulding width is used to match the stock on hand.

4 - Rabbet Width/Lip

The rabbet is the step around the frame that holds the backing materials in place. It will obscure the mat slightly and limit the maximum possible window. Most frames use a 1/4" lip though in this case to make manufacturing easier this frame will use 3/8" rabbet width

5 - Rabbet Depth

The Rabbet Depth is how much material will fit inside the frame.

Glass - The transparent material that protects the print

- The transparent material that protects the print Mat - The cut out border around the print

- The cut out border around the print Print - The artwork being displayed

- The artwork being displayed Backing - A structural layer that holds the print in place

- A structural layer that holds the print in place Point - A specialized nail that is hammered into the frame and holds the layers against the rabbet

Each of the layers is measured:

Layer Thickness (inch) Glass 0.10 Mat 0.01 Print 0.01 Backing 0.05 Point 0.15

The total thickness is 0.32" , meaning 0.375" or 3/8" will leave adequate clearance for any future needs

6 - Moulding Height

With a rabbet width and depth of 3/8" we can leave an additional 3/8" of material remaining meaning the total thickness of moulding is 3/4"

Putting it all together

Putting all of those numbers together this is the exact frame profile:

A FreeCAD model demonstrating cross section dimensions

post-editing note: If I had seen this to-scale drawing before making the part I would have narrowed it sooner

Calculating Outsize Size

The outside size is based on a stackup of

Moulding Width - Width of the material

- Width of the material Rabbet Width - Inset amount subtracted from the material

- Inset amount subtracted from the material Allowance - Extra width on the rabbet to allow for inexactly cut prints, backing, and glass

- Extra width on the rabbet to allow for inexactly cut prints, backing, and glass Frame Size - Goal inner size

Adding together the various widths:

step calculation (inches) full formula (moulding width - rabbet width) * 2 + allowance + frame size base moulding width 2" minus rabbet width 2 - 0.375 = 1.625" doubled because two sides 1.625 * 2 = 3.25" plus allowance 3.25 + 0.25 = 3.5" total outside width 3.5 + 8 = 11.5" total outside height 3.5 + 10 = 13.5"

And thus we get:

A FreeCAD model demonstrating profile dimensions

Freecad Document

In the follow up post Making a Frame: Practice this design is brought to life