Miter Cuts: Tips and Frustrations

In last issue’s eZine editorial, Rob confessed to having problems cutting miters. In the true spirit of misery loves company, it turns out he is not alone. – Editor

“Hate is not strong enough when it comes to miter joints. I am about to buy some expensive composite decking, and the pattern my wife has decided upon calls for numerous miter joints. I anxiously await to read on how–to tricks to get accurate miter joints.” – Al Phillips

“I chuckled when reading your post about the frustrating miter joint(s).  Being an ol’ woodshop teacher, you think I’d have it ‘down pat’ by now, but I fall into the same category with you. I think I’ve built 4-5 jigs over the years, but I have fairly good luck with one of them. I have to admit it’s not ‘right-on’ but between an old  45-degree drafting triangle, a deck of cards and some file cards I usually get it close enough for a passing grade. I sandwich the cards between the frame and the rail on the jig and usually alter the angle enough to get it close, but as you know … the correction is x4!! The best way around it all: when someone asks you to make a frame … send them to Hobby Lobby!” – Frank Cackowski

“Rob, I always look forward to your blurb at the beginning of the WJ eZine. They always seem to be on the mark. I am just getting  more serious about woodworking after I retired. After going through the cutting board phase, I’m now working on keepsake boxes. By far, the mitered corners are the hardest thing to get right. I can’t say how glad I am that even you have problems with miters. I thought it was just me.” – Greg Mansker

“I, too have trouble with miters! I have been woodworking for 30 years and sometimes I struggle to get gapless miters! I am eager to see what your readers have to say!” – Denny Grant

Cutting miters has even put some friendships to the test. – Editor

“I have my own troubles with that, hired a friend to assist on one project, he insisted on drawing a chop saw to the end of its travel on the tubes and pushing the blade into the cut. That failed miserably despite repeatedly checking the miter with a gauge blade to fence. So, never do that. After my good buddy had trashed a stick of material with his ‘technique’ I cheerfully shared a beer with him and sent him on his merry way. Checked the saw later by gauging the angle (despite preset click, never trust that there) and used the saw as manufacturer intended by dropping the blade into the material and pulling it through and, voila, far better results. My friend is still a friend but no longer remotely interested in his bizarre ‘technique.’” – Paul Sherman

But, it seems that some woodworkers have found miter cutting techniques that do work for them. – Editor

“Every time I go to make a miter cut that really means something, I check my miter gauge for accuracy and I also make sure the square is accurate.  That can be really frustrating to cut a good piece of wood that does not fit and find out that there is a problem with the square.  One of my most reliable squares I found was not square.” – Frank Kay

“I scribe lines at 30, 45, & 90 degrees left and right with a drafting square on the saw table.” –  Bob Peter

“Cut your miters on the table saw or chop saw then pull out your miter plane and shootimg board! True up the saw cuts in one or two passes of the miter plane and you will have perfect miters every time!” – Clint Struthers

“I think that it is really important to have a set of scrap pieces to try the cut. Measure the corner to see if your corner is an accurate 90° or whatever.
I recently had to cut a mitered frame that had a 3″ front rail, 2″ side rails and a 1″ back rail. The miters were straight miters from the outside corner to the inside corner so it meant some acute angle cuts. I used a layout with the miters drawn in, a protractor and lots of test cuts.” – Chris Barker

And, for some, commercial jigs and gauges have been the answer. – Editor

“I’ve struggled with this as well, but no more.  I took a page from the machinists in the world and bought a NOGA magnetic gauge holder and dial indicator.  The first order of business is to get your blade parallel to the fence with as much accuracy as you can muster.  I then used a precision square, which I clamped to my miter gauge head with the miter gauge at 90 degrees to blade.  I then adjusted the miter gauge head until I had less than 0.001″ of deflection over 8.5″ of travel.  Once that is complete, you can swing the miter gauge over to 45 degrees and then check the alignment again using the 45 degree angle on the square.

“Excessive?  Maybe.  But on the other hand, I’m confident that when I set the miter gauge to an angle, I’m getting the angle I expect. The Incra miter gauges help with this as they have detents for every degree of rotation and a vernier for sub-degree settings.

“My only regret is that I didn’t realize how useful the NOGA/dial indicator combination would be until after I finally broke down and bought it.  Should have done it years ago.” –  Dr. Smith

“This is probably overkill, but I do cut my miters only once. Obviously, the table saw needs to be well tuned-up. First, I use a digital ‘tilt’ box to make sure the blade is precisely set 90 degrees to the table top. I have the luxury of having two Incra miter gauges with long fences.  Use stop blocks to insure that matching sides are exactly the same length. Set one gauge at 45 degrees (to the blade) in the left miter slot using a precision engineering 45 degree angle.  Set the other gauge at 45 degrees in the right slot, again using the precision angle. Then use a precision engineering square between the two miter gauges to confirm they are exactly at right angles to each other.  Tweak the setup as necessary to insure accuracy.  Cut one side of each miter using one gauge.  Cut the other sides using the other gauge, with a stop block to get matching lengths. Sounds like a lot of work to do the setup.  But once you’ve done it several times, it only takes a few minutes. Much less time than having to recut all your joints. Guess thiss is an extreme case of ‘Measure twice, cut once.’”- Ken Kuszynski

“The Osborne EB-3 miter gauge. Dead accurate right out of the box, accurate, positive detents every 5 degrees and at 22-1/2 and 67-1/2 degrees. Miters are child’s play and even octagons fit first time.” – Ralph Bagnall

“I have found the plastic miter sled from Rockler to be very accurate.” – Bernie L

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