With the Mitertite system, mitered door and window casings can be screwed together as a unit, allowing trim carpenters to install pre-assembled casings. Once you get used to this technique, it can improve the quality of your work and save time.
Overall I'm impressed with the Mitertite, but it does have a few drawbacks. The learning curve is steeper and setup takes longer than starting out with most new tools. You have to be patient, and you really do have to read the instructions. It also helps to use Mitertite with a large work surface – a sheet of plywood set out on sawhorses, at the very least.
The basic tool is an "assembly plate," a unique pocket-hole jig that holds two pieces of mitered casing together for drilling and assembly with a pocket-hole screw. The rocker clamp on the assembly plate holds both pieces of casing together for drilling and assembly. The rocker clamp feet can dent casing if you're not careful, so you might want to protect the work. I also found it helpful to use another clamp on the outside of the miter; I borrowed a clamp from my Kreg jig.
Over time, mitered casings usually open in the inside corner of the miter. The Mitertite system addresses this with a micro fence that you fit to your saw and set to overcut the miters by 1/10 degree (this splays out the legs of a door casing by 1/5 degree on each side). Having miters cut that are 1/5 degree wider than 90 degrees would not seem to matter much, but the reveal at the bottom of a doorway will be doubled. As a door casing set is installed, the splayed legs are pulled in, compressing the inside of the miter. This works because the screw holding the outside of the miter together forces the inside of the miter together without opening the outside.
The micro fence has a set screw, which allows the side of the auxiliary fence closest to the blade to be pushed away from the saw's fence just a few thousandths of an inch. This provides for the miters to be overcut by 1/10 degree. Once the micro fences are calibrated and their mounting blocks are attached to fit your saw's fence, the micro fences are set for dedicated use with that saw only. This presents a problem for carpenters who, like me, use a variety of miter saws. I would need several sets of custom-calibrated micro fences. The micro fence could use some refinement; better provision for attachment and adaptability for use on multiple saws would be nice, in my opinion.
Stretch clamps are provided to help pull the miter together and keep the two members making the joint from rotating around the single pocket screw. The stretch clamps are a great product all by themselves and will find other uses apart from the Mitertite application.
Mitertite claims to be "fast, tight, and permanent." It certainly is capable of making tight joints that can be expected to fare well over time – but the "fast" claim must be qualified. Initial setup aside, the tool still requires setting up a Mitertite workstation with an assembly table on the job site. However, this system then allows efficient pre-assembly of casing sets, which can be installed quickly as units. This is great if everything goes right the first time. Disassembly and recutting are to be avoided; one mistake and time gains are wiped out. So measure carefully and check openings for squareness.
Another time-consuming step is cutting plugs and installing them for situations where the holes drilled in the head casings are visible from above. A plug-cutter is provided for this. Fortunately this is not an overly common task, and if back-banding is part of the casing style, the holes are covered by molding.
Mitertite is an innovative product that will be appeal to serious trim carpenters. It's a tool that asks the user to adopt a casing pre-assembly system that can be a paradigm shift. If you already use pocket-hole jigs to pre-assemble flat 1-by casing sets, or if you like using clam or spring miter clamps, this system is a logical extension and is worth considering. It has a few rough edges, but the resulting tight joints and long-term stability of the miter – plus the assembly-line efficiency possible with the system – seem well worth the $297 price.
Brian Campbell owns Basswood Architectural Carpentry in Winona, Minn.
COLLINS TOOL CO.