## Friday, January 21, 2011

### Making Cabinet Doors - Without the Tricky Math

The first time I made cabinet doors, I just about had a heart attack.  The amount of planning, and the exactness needed to have everything come together, was daunting!  Knowing that I needed to figure the sizes of all of the pieces was WAY worse.  "How do I figure out the size of the panel.  How long are the rails?  Those were math equations that had me questioning my dimensions and sanity until the project was complete.

Well, with a bit of practice, and some trial and error, I have finally come up with a simple way to make doors without any complicated math.

The internet is filled with tutorials on how to make doors.  You will find everything from proportions, to molding profiles, to seasonal movement.  However when I stumble upon those articles, almost all of them glaze over the most important part.  Making the pieces the correct size.

I've built well over a thousand doors in the last few years.  Sometimes it's just two, and sometimes it's 87.  There are A LOT of pieces that all need to machined to the correct dimension.  For example.  The current project I am working on has 829 individual pieces of wood that will comprise the final number of finished doors.  ANY miscalculation in these dimensions can be very costly in labor, material, and to the work schedule.

A while back I created a very simple spreadsheet that takes all of the math out of the equation.  Enter the overall size of the door.  Then enter with width of the rails and stiles, and POOF!!  Your done.  The spreadsheet does the rest.  It gives you the size and quantity of every piece in the door.

Below is a simple screen-shot from the program.  It is a bare bones program that works.  No need to buy any complicated programs or spend a bunch of time sitting at the computer when we would all rather be working in the shop.  I generated this cut-list in about 30 minutes.  That included double checking the numbers in the shop with finished face frames.

Please allow me to explain the 'math' part quickly.  Once you have your overall door size, determining the individual parts is not hard.  HOWEVER, its really important to eliminate the possibility of human error.

The basic equation for rail length is **overall width-minus two of the stile widths, plus two of the tongue lengths.
• example 1: 12" wide door, with 2 1/4" stile widths, with a 3/8" tongue length= 8 1/4" rail length
• example 2: 22 3/8" wide door, with 3" stile widths, with a 1/2" tongue length=17 3/8" rail length

Door panels are basically the same except you need to allow for some seasonal movement, so in most cases I choose to keep 1/16" on all four sides of the panel.  Don't forget you have to do the same math for the height as well.
• example 3: 12" wide door, with 2 1/4" stile widths, with a 3/8" tongue length=8 1/8" wide panel
• example 4: 22 3/8" tall door, with 2 1/4" top stile width, and a 5" bottom stile width, with 1/2" tongue =16" tall panel

As you can see, the math is pretty simple.  It is a far cry from understanding some crazy physics equation.  However, there are pleny of opportunities for the brain to take a quick break and provide some REALLY wrong numbers.

If you send me an email, I will happily send you the file for your computer.  I created it in Open Office.  (a program that does just about everything Microsoft Office does.  Except it's FREE)  Just let me know what spreadsheet program your working with and I'll format it up for you.

With a bit of practice, and a bit of tinkering around, you'll be back in the shop in no time flat.  In my next post, I take the cut-list to the shop and see how I did.

Do any of my woodworking reader have a preferred method for making a cut-list for doors?