The Art of Sneaking Up on the Perfect Length

Have you ever needed to cut a board on your miter saw to say, exactly 12 inches?  After careful setup and cutting, just to be sure, you measure and you find your cut is really 12 inches + oh... a smidgeon.  Rats, now what? I guess if you have plenty of time to kill, you could sand it. Or perhaps you could decide you're gonna 'fix it'.  Brimming with confidence, you stride back to the miter saw to trim that smidgeon off. Only then do you discover you actually trimmed 2 1/2 smidgeons off, and now all your board is good for is practicing your jump shot into the scrap bucket.

My personal record for doing this is 3 times for want of a single board. (At this point I decided to call it a day and went to a local bar.)

Great care is not always enough. Psychology may be at play here. We sure enough don't want that board to be 11 and 15/16.  So it's a natural tendency to say 'if I miss, I want to miss long'.  But missing a little long is only useful if we have a way to truly 'fix it'.

Sometimes, such as in the case of the first photo below, you will really, really need a cut to be perfect.  And there is a solution; I just wish I remembered where I first read this technique. I'd like to give attribution as it has surely saved me plenty of heart-ache.   But alas, the aging process of my brain continues unabated.

So here is how you can sneak up to a perfect length cut with a miter saw.

- The face of a saw blade is a tiny, predictable bit narrower than the blade's cutting teeth. It turns out to be just about 1/32nd of an inch (1/64th on each side).  So to use this fact when it just has to be perfect, 1st intentionally cut the piece slightly over length. 

 - Next, with the power off, pull the miter saw blade down.  Be very careful here not to inadvertently start the saw, especially if your trigger is built into the handle. 

 - With the power off, the blade down, fingers off the trigger, butt the board up against the face (not teeth) of the blade. See photo 2 below.

 - ABSOLUTELY DO NOT start the saw in this position.  With the power still off and a firm grip on the board raise the blade.  It should just scrape the board on the way up.  With the board still locked in position -all the normal safety rules apply here- make your cut. 

 - You'll find that you trimmed just about a 64th off, likely all as sawdust. Now measure or test for fit. It may take a few passes depending on how much you over-cut, but that is the point of sneaking up on it. Soon you will have that board at the perfect length.

Note: I have not used a sliding compound miter saw and thus cannot tell you if these instructions would apply to that type of miter saw.  If you have such a saw, please be careful and look for any safety issues that might apply to using a technique similar to this with that type of saw.