Tag Archives: cut list

Stuck in the Middle

The beginning of your process in building a prop can take awhile with no apparent progress. First, you have a lot of research to get the look and design figured out. You may need to make construction drawings, sketches, or even full-scale layouts. Choosing your materials, deciding on techniques and planning the order of tasks can also take some time. Depending on the type of prop you are building you may need to generate cut lists, construct jigs and templates or draw up patterns. Even just gathering or ordering your materials and parts can take up time. In other words, you can spend hours or even days upon starting a project before the prop itself begins to take shape.

In a similar vein, the end of the process can be a slow ordeal. Filling and sanding, coating and painting, or whatever your finishing touches are usually take a lot more time than you anticipate. I’ve found for projects which require a smooth or pristine finish, the sanding and smoothing part can take longer than the construction of the prop itself. Anyone who has painted can also attest that the preparation of the surface and masking out of areas is the longest part of the process; the actual application of paint is but a blip in the overall time frame of the process. Like the beginning of the process, the end can take a significantly longer amount of time than the construction of the prop.

It is usually the middle which takes the fastest. You spend a few days planning the prop out, than in one afternoon, all the pieces go together like magic. Then it takes another few days to get it to a finished state. It is this middle phase where progress on the prop is the most visual, that is, when it seems you are working the fastest. But a quick construction period can only happen with thorough planning, and a well-made prop can only result from thorough finishing.

Revised drawing showing thicknesses

A Common Error in Making Cutlists

One way to begin with a carpentry project is to make a cut list. You break apart the drawing into all the parts, figure out the measurements for each of those parts, and draw up a list of how big each piece should be. Perhaps the most common error in developing a cut list is neglecting the thickness of the pieces. Let’s say you want to build a cube which is one foot on each side. A perfect cube. A solid cube will be built with six pieces of wood. For this exercise, let us say you will build it with scraps of ¾” plywood you have laying around the shop. If you make a drawing of a cube, you may assume you need to cut six pieces one foot long and one foot wide.

A one-foot cube
A one-foot cube

Wrong!

Let’s look at the drawing again.

The top and the bottom can be one foot by one foot. However, if you make the front and the back one foot by one foot, the cube will end up being one foot by one foot, one and a half inches. See? You need to subtract the thickness of both the top and bottom from the length of the front and the back. In this case, ¾” and ¾” is an inch and a half, so the length of the front and the back would be 10 ½ inches. The width remains one foot.

Revised drawing showing thicknesses
Revised drawing showing thicknesses

The sides need the thicknesses of the materials taken away from both the length and the width. In other words, it will be 10 ½” by 10 ½”. So our final cut list looks like this:

  • 2 pieces at 1′-0” x 1′-0”
  • 2 pieces at 10 ½” x 1′-0”
  • 2 pieces at 10 ½” x 10 ½”

At this point I wish to add a caveat. Plywood does not come in exact measurements. While it is sold as ¾” thickness (or ½” or what have you), the actual measurements vary. Three quarter inch construction plywood is actually 23/32”. In some cases, you may not care about a thirty-second of an inch difference, though in others you may. One sure-proof method for accounting for the actual thicknesses of materials is to hold two pieces on the piece you are measuring and make your mark using them as a guide.

An easy way to account for thicknesses
An easy way to account for thicknesses

Now, in props, there is no reason to try and create a cut list for all the parts at the beginning before you begin working. Sometimes, it is nearly impossible to do all the math to discern the measurements of every single piece. Other times, you need to build a section and look at it so you can visualize the next portion of what you are building. It is not always necessary to have a project completely mapped out in your head at the outset, because better solutions may become apparent as the prop comes into being.

I’ve posted before about the importance of precision in cut lists. You will also find a link to a wonderful series at Popular Woodworking which has a more in-depth look at cut lists.

Precision and Cut lists

Whenever I take on a carpentry project, or a similarly precise prop, I try to get my drawings and plan as precise as possible. For the first pieces I measure and cut, I try and be accurate down to the 32nd of an inch. By the time you get to the end of a project, you will find that the imprecisions of your tools and the imperfections of the materials will give you grief in the form of gaps, overhangs, or pieces not fitting where they should. These problems should be minor enough where a little sanding, wood filler, or sheer muscle power will set everything in order. If you start off with sloppy measuring in the beginning of your project, however, these gaffes will have swelled to horrible and glaring errors by the time you’re putting the last few pieces together.

The folks over at Popular Woodworking recently posted an article about making a cut list, and they put this argument much more eloquently than I just did:

If you miss the mark on one of these numbers early on, then you set off a chain reaction, and turn the remaining parts into a row of falling dominoes. It’s easy to think that a bunch of little errors will cancel each other out, but the opposite is true. All those little errors will congregate at the most visible place on the finished piece they can find. Once there, they will hold a party to mock you.

Check out Making a Cut List Part 1 and Part 2. It has a lot of great ideas on how and when to use and develop a  cut list when building furniture pieces, whether you’re just starting in carpentry, or you’ve been at it for a few years.