Consumers often assume that the piece of wood dictates how beautiful the finished piece of lumber is, but the millwork is another deciding factor. The highest quality board can quickly be ruined by poor cuts in the mill. That is why quality control is important in millwork.
Mills need to focus on the blades, feed rates and board support in their facilities to ensure that their finished products are as beautiful as the boards they use to create them. Machines need to be carefully tuned on a regular basis to ensure that they are working well and not damaging the wood. The J. Gibson McIlvain Company (site) understands this and focuses on quality control in its mills in addition to a focus on choosing the right basic materials prior to processing.
J. Gibson McIlvain is not the only entity keeping an eye on millwork quality control, however. The Architectural Woodwork Institute (AWI) has standards in place as well, and mills have to meet these standards in order to meet certification. For instance, the AWI dictates that 21 to 22 knife marks per square inch of material is the maximum allowed. Interestingly, this standard still creates a finished product with very clearly visible knife marks once it is finished.
At J. Gibson McIlvain, the company found that their machine was making about 13 to 15 knife marks per inch. When these products were finished and installed, the knife marks were clearly visible. This was not acceptable to discerning customers.
In order to combat this problem, the company went through a painstaking process of adjusting and readjusting their machines to cut down on these knife marks. The process involved several subtle changes, but the end result was a properly milled board that had few visible knife marks. This type of tuning has to be done on a regular basis in order to turn out the highest quality finished products. When working with highly discerning customers and the high quality boards that J. Gibson McIlvain has, this process is absolutely necessary.
This fine tuning process is not a “fix it and forget it” step. The machines have to be constantly adjusted and tweaked to prevent knife marks. The final product needs to be regularly inspected to ensure that there are not further adjustments that need to be made. In fact, sometimes adjustments are required simply when switching from a hard species of wood to a softer species, because each type of wood reacts differently to the milling process.
Not all mills will put the effort into maintaining this level of quality control. They will do what is necessary to maintain AWI standards and nothing more. Customers who are interested in finished pieces with as few knife marks as possible need to find a high quality mill from which to purchase their pieces.