Canadian Woodworking

Miter trimmer

When cutting miters with a table, miter, or band saw it’s not uncommon to end up with miters that don’t mate perfectly together, or that tear out. You could use a hand plane and a shooting board to clean up the cuts, but if you’re not careful, you might still round over the edges of the miters.

The Miter Trimmer is an archaic looking tool that resembles a paper trimmer (or guillotine). But don’t let the look fool you – this tool enables you to cut glass-smooth, perfectly fitting miters quickly and efficiently.

Using a Miter Trimmer is a cinch. Pre-cut your stock slightly oversized, about ⅛” will do. If you have a lot of pieces to trim, do the pre-cutting on the table saw, otherwise pre-cut them with a handsaw. Then trim the miters with the trimmer. It’s as simple as that. For angles other than 45º loosen a pin stop and move the arm to the required angle. Use a bevel square to set the angle. For compound miters cut a block of wood to the desired angle and slip it under your stock for the second cut. Remember, this is a shearing machine – don’t use it to make through cuts. It will trim stock up to 6″ wide and 4″ thick. When using the Miter Trimmer, hold the stock flush against the pivoting arm and push the handle with your other hand. Use a slow, smooth and steady motion rather than a quick and jerky movement.

The trimmer is made from machined cast iron, weighing in at about 30 pounds, which provides for a lot of stability in use. The business ends of the trimmer are the high-speed steel blades. Treat them with respect, they are very sharp. Machine screws hold the blades in place, and make for quick removal when they need to be rehoned (only hone the bevels) or re-sharpened: it’s best to send them out to a blade sharpening service. The blades are angled to provide a shearing cut. A simple rack and pinion gear moves the blades (regularly clean the debris out of the track and spray it with a lubricant, such as WD40).

miter trimmer

The unit I tested needed a slight adjustment. I set up one of the blades to cut at 45º and the other at 90º. To adjust the pivoting arms at exactly 45º, simply loosen the set screws that hold the pin stop assembly in place and re-adjust. Check your angle with a protractor or miter square. Then cut two pieces of stock, checking their fit. Readjust the pin stop if necessary. To adjust the other pivoting arm for a perfectly flush cut, loosen the screw on the eccentric brass washer, and turn the washer until the gauge stops at 90º, tighten the screw and make a test cut. Again, readjust if necessary.

miter trimmer
Adjusting the eccentric washer for a perfect 90º
miter trimmer
Adjusting the pin stop assembly

I made perfect cuts on a variety of softwood and hardwood. As you might expect, take thinner cuts on harder woods. You literally want to ‘shave off’ the wood.

This is a great tool for furniture makers, finish carpenters, door makers, cabinetmakers, picture frame makers, in fact, anyone who wants perfectly made miters.

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Carl Duguay - [email protected]

Carl is a Victoria-based furniture maker and the web editor at Canadian Woodworking & Home Improvement.

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