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Im new to using a circular saw and would like to improve my accuracy, If I have a blade that is 2mm thick do I add this on after the current line that I have marked and then cut down that? Thanks

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    Include the thickness of the blade in the waste. That way you don't need to measure (or really care about) the precise thickness of the blade. – DaveInCaz Mar 17 at 14:28
  • I don't understand the question. There's nothing to add. Obviously if you cut down the center of the line the board you're using will be too short. – isherwood Mar 18 at 15:40
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A circular saw isn't a super precise cutting tool so you'll want to keep that in mind. Lining the notch on the shoe is not going to give you super accurate cuts. Its fine for framing but may not be for other tasks.

To me a cutting guide is the best way to improve your accuracy. They are very cheap and easy to make, and they speed up your work quite a bit.

Here's a link to one of many how-to's: making a cutting guide

cutting guide

If you make your marks on the waste side of the measurement, you can quickly and easily line up the guide to the edge of the mark, and get a pretty darn close to perfect cut quick and easy.

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One always cuts on the waste side of the line with whatever cutting tool that is being used.

Trimming exactly down to size, ie the line, is usually done with something that gives a finer finish. For wood I use a router and usually clamp a guide to the work if possible.

  • Thanks, I am now cutting on the waste side but I was wondering to get as accurate as possible I take it I cut the width of the blade after the line? – ORStudios Mar 17 at 13:12
  • I cut as close as possible, less to remove to finish - often with wood I use a router... – Solar Mike Mar 17 at 13:13
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    @ORStudios When you've drawn your cut line, draw an arrow on the good side of the line pointing toward the waste side (this way you can't inadvertently cut on the wrong side of the line... the arrow always points toward the waste). When cutting, the entirety of the blade should be on the waste side of the board. – stevieb Mar 17 at 14:35
  • A router to cut? The question was about a circular saw. - – Ed Beal Mar 17 at 16:28
  • @EdBeal after you have cut to length with a circular saw, THEN I use a router to give a fine finish... About the only saw I have used that only needs sanding or light chisel work after is a dovetail saw... – Solar Mike Mar 17 at 16:30
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It really dosenot matter, we all may do it slightly different, one answer says make the arrow on the good side, I was taught make the mark on the cut side. What matters is that you cut at the measured point, I use the notch on my saws to get close but actually look at the blade in relation to the cut if it needs to be close. With framing a blade width is not a big deal but you will find once you pick a method, measure 2x and cut once you will get a repeatable length. Make sure to use a Square so your cuts are at a 90 this is more important than a slight length difference in my opinion.

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    Fixed your downvote problem... but am reminded of a good story. Lead carpenter would mark the stud and tell the apprentice to leave half the pencil line. Apprentice found that tough, so cut the line and then ran the pencil lead at 45 degrees along the cut to make it look like half a line. Took the lead about a half a day to figure out he'd been scammed. – Aloysius Defenestrate Mar 18 at 1:11
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It really comes down to what your error tolerance is, and then personal preference.

For coarse cuts, such as those needed for rough framing, you generally don't need to sweat this small detail.

For more precise cutting, you'll want to consider a number of factors, including (a) the actual width of the cut from the saw blade (its "kerf"), (b) the thickness of your pencil marks, and (c) your ability to cut exactly along the intended line.

You can handle (a) and (b) by choosing a convention based on personal preference. For example, that the resulting piece of material should go up to the pencil mark, but should not include it. Once you have that convention in place, it's a matter of adhering to it when making your marks and when positioning your saw blade.

Handling (c) is a whole topic unto itself, but there's no shortage of products, tricks, and internet videos to help you with that part.

If you're coordinating your work with other people, you'd need to make sure you're all on the same page. I don't know if there's some convention regarding this that's widely assumed throughout the construction industry.

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If you need a peice of wood 10cm long from a 20cm peice, you mark your line at 10cm. But your blade will make 2 cuts one at 10cm and one at 9.8cm if measured from the other side. Normally you cut off the waste because the peice you are measuring is what you want. Sometimes you need to add the blade. If you are marking 3 pieces at 10cm off a 40cm peice your first mark is 10cm then 20.2cm and 30.4cm.

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You should measure and mark like someone else is cutting. If your board needs to be 47 1/16" your mark should be straight at that exact length.

Someone who is accurately cutting should cut so that you see the mark but no gap.

That brings up another point. This is why people mark with a pencil. I have worked with guys who mark with a sharpie or marker and it is like why even measure? Your line is 1/8" thick. Where do I cut this?

Marking this with a carpenter's pencil, marking it at the accurate location, and cutting it right is not only an art but an assembly procedure for any crew. If you have a 3 or 4 man crew framing - especially during a build - the guy marking will often not be cutting.

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