Friday, October 19, 2007
The Cut List
Now that we've designed the cabinet, we have to figure out how much wood we will need to make it. Just how do you do that? Each part in your project requires a certain amount of wood. Each has a thickness, a width and a length. When you designed the project, you figured out what all of the parts were and what their dimensions have to be. So you basically create a list of all of these parts, listing where they go in the final assembly as well as their names, thickness, width, length, and what kind of wood you want to use to make them. If you have more than one copy of a part, you can just write down you need so many copies of it, rather than list it multiple times. This list is your cut list. From the cut list you can determine how much wood you need to buy. Once you know how much wood you need to buy, you can estimate how much the materials will cost. And once you know what it will cost, you know just how expensive this hobby can be. Talk about frightening . . . and it's not even Halloween yet! If you use Google SketchUp to design your project, you can actually use it to create your cut list. SketchUp uses the Ruby Script scripting language as an automation tool. There are lots of clever people out there who have the free time to write some cool Ruby scripts for SketchUp (they obviously don't have kids). One of these will generate an exploded view of your project (available at smustard.com for $10). Another will generate a CSV (comma separated values) file containing your cut list that you can import into Excel or some other spreadsheet program. You can download this Ruby script for free here. Once you have your cut list, there's another program that you can use to estimate how much stock to buy. This is called CutList Plus. I do use CutList Plus, which has a "Silver Edition" which costs about $70 to purchase and is more than adequate for my needs. The output that it generates is extensive, because it's intended to be used by someone who is pricing a job & generating estimates. You get additional features with the Gold Edition, but you have to pay more, too. To use software like CutList Plus, you first enter the various sizes and prices of different kinds of stock at vendors near you. You next import the CSV file created by the SketchUp Ruby Script into the program, or you hand enter the cut list if you don't have SketchUp or the cut list Ruby script. The software next determines how many boards you need to buy at what sizes, how many sheets of plywood you need, etc. It even takes waste into account. When it's done with its analysis, the program tells you how much the materials will cost and how to cut each part from the stock. This last bit is a little problematic. Programs like CutList Plus can't take into account the grain of the specific boards you purchase, so it really can't tell you the best way to cut your stock into parts. You have to use a little judgement when laying out the parts for your project from the stock to choose the best looking grain & orient the parts relative to the grain (more on that another time). This basically means there could be more waste from a board than the program computed, and / or you can't cut all of the parts from that board the program computed you could. Still, software like CutList Plus will get you in the ball park, as far as cost and amount of stock you'll need. You just need to remember to buy a one or two boards more than CutList says you need. Having the extra stock also comes in handy should you accidentally trash a part while you're making it (not that I've ever done this myself. This is my story & I'm sticking to it!) Next time, we'll talk about choosing the materials. Fun!