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Building wooden furniture doors
and calculating the size of door components

Build or buy

Many woodworkers "outsource" their doors - buy factory made doors for their furniture. Excellent quality doors are available from many vendors. But my choice is normally to build the doors because I can use wood from the same batch as other wood in the project (better color matching), and my volume is small - not worth the effort of placing and order and waiting for delivery.

Spreadsheet for the calculations

Feel free to download this Excel spreadsheet to help with the calculations. (Click on the link to open it, then save it on your machine, or right click on the link and "save target as..."). I saw a similar calculator available on the internet for $25 - if you would like to send me $25, feel free to do so, but this one is free. This page is about how to customize and use this spreadsheet. There are no macros or other programs in the spreadsheet - nothing that could harm your computer.

Customizing the spreadsheet

You will have to turn protection off (under tools) and unfreeze panes (under Windows) to change the setup, but I recommend you turn the protection and frozen panes back on and save the spreadsheet before use, so you don't accidentally change any of the formulas.

Rail/stile width is set in cell N1. Default is 2 inches, which I like in most cases. It is wide enough to provide support and handle hinges, but not so wide that wood movement becomes a problem.

Moulding width is set in cell N2. Most rail/stile cutters cut a simulated 3/8 inch wide moulding in the sides of the rail and stile. Some people would call the overall width 2 3/8 inches, but the calculations in this sheet are made based on separate rail width and moulding width.

Depth of slot - cell N3. Most of the rail and stile cutters I have owned cut a slot equal to the depth of the moulding, but I recently bought a "premium" cutter that makes a deeper slot - 1/2 inch rather than 3/8 - for greater strength as the rails and stiles are glued together. This means the wood to cut the rails need to be 1/4 inch longer.

Extra size... Trim Edge. I like to build doors 1/8 inch larger than required on each side, so when I am done, I can trim the edges on the saw, assuring smooth glue-free end grain on the tops and bottoms, and perfect square on the doors. If I have tear out as I am cutting the profile on the edges of the rail and stile, I can cut 1/16 to 1/8 off the torn-out edge, and cut the profile again (taking the wood I would have later used to square the door). Set cell N4 to the amount you want available to trim, or if you don't want this "feature" set the trim edge to 0.

Many door makers like to cut the edge profile in all the pieces in advance. When figuring the total length needed, the width of the cross-cut saw kerf should be included. That width is in cell N5

If you are using space balls or other pads to keep a raised panel centered, and keep it from rattling, you need to leave room for the compressed space ball. The recommended space for the common 1/4 inch space ball after compression is 5/32, for a little less than 50% compression. If you need 5/32 on each side, overall the raised panel should be 5/16 smaller. Set the size you want raised panels reduced in cell N6. This is only applied to "raised panel" calculations, and only raised panels are included in the overall wood requirement.

Normally glass will be slightly smaller than the opening - most glass shops glue in the glass with silicone rubber, or provide a spacer around the glass. N7 is the amount that the size of the glass is smaller than the opening.

Flat panels are assumed to be plywood or other material. The dimensions of the panel are the same as the opening, and the material required in not included in the total wood required. If you don't want any calculation of the panel size, leave the type of panel (Column E) empty

If a door is too small, there may not be enough room to have an attractive raised panel. If an overall door dimension is less than the dimension you specify in N8, the spreadsheet will give a warning error if you specify a raised panel, and suggest you consider a flat panel.

Don't change the formulas in column O of the setup area... those are calculated once to make other formulas simpler. After the setup is complete, turn "protection" and "freeze panes" back on, and save the "master" copy of the spreadsheet, now that it incorporates your preferences.

Using the spreadsheet

Start by putting the project name in cell F9 and saving the spreadsheet with a file name related to the project. This will leave the master copy of the spreadsheet available unchanged for other projects

Starting in row 12, enter an identifier for the door, and the quantity required of that particular size door. This can be a short name or ID number you can put on the parts, and on the door, during construction.

Normally the stiles go the full height of the doors, and the rails are horizontal between the stiles. Therefore enter the door height as the final dimension of the door in the direction of the stiles, and the door width as the final dimension of the door in the direction of the rails.

From the drop box in column E, choose the calculations for the center panel...

As data is entered, the total length of the rails and stiles (plus saw kerf) are calculated in inches as well as feet and inches. The overall wood required is also calculated in square feet (board feet assuming all parts are less than 1 inch thick). In practice I have found that there is about 25% waste when making doors from normal hardwood, not considering loss for knots and sapwood. You may enter any waste percentage you find useful, and the total wood required will be calculated.

If you print the completed sheet and take it to the shop, you will find the number of doors repeated among the dimensions, to assist you "checking off" the components as they are cut.