Compound sliding /mitre saw accurate cuts

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25 Apr 2022
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Hi guys, I’m struggling to make precise cuts on my mitre saw (mostly simple 90 cuts) do I cut on the pencil line? Just before? Just after?. Accurate cutting is a must for my latest project. Any help/Tips greatly appreciated

Left or right of the line depends purely on which side us to be finished size. If finish piece is on left then cut on the right and vice versa when finish is on the right you cut to left of line.

Re not at 90, is the cut not 90 front to back, or not 90 top to bottom?
Left or right of the line depends purely on which side us to be finished size. If finish piece is on left then cut on the right and vice versa when finish is on the right you cut to left of line.

Re not at 90, is the cut not 90 front to back, or not 90 top to bottom?
Thanks for the reply, the cut is of perfect consistency, it’s just either too long or too short, maybe I need T take blade kerf into account??
A pencil line is about 1/2mm thick.
So you can cut on the left of it, on the right of it, through the middle, or nearly through the middle thus dividing your pencil line into 5.
Left side too tight, right side too slack. Middle either. Through the line on the left of middle just right, through the right of middle still too slack.
You measure out and mark your length.... then you have to cut either to split the pencil line, or just after it on the waste side so you can trim back if its too long.
What make / model is the saw? There'll most likely be a lever on the back to allow it to tilt over sideways and the front section will have a lever to let it turn to the left or right.
You'll need a square that is accurate.
Check the left to right with the square. Some saws have 90, 45, 22.5 as preset notches.
Using your square again ( machine unplugged ) drop the blade to activate the guard / move it out the way and hold the square on the bed and slide it up agaist the blade ( vertically) and adjust as necessary.

Make sure you keep those pinkies away from the danger zone. You can clamp timber in place or use an offcut to apply pressure 👍
If you want to cut multiple parts the same length then use a stop block.
As the others have said measure from the side of the blade (outmost tooth edge). Stop block can be as simple as a bit of wood and a clamp.
I looked at a few clips before finding this guy using a stop safely. You dont want to pinch the wood both sides of the blade.
Making repetitive cuts using a stop block and a miter saw.. - YouTube
It is probably a crude way, but I start the saw but don’t cut and release the power, then lower the blade just far enough to make the tiniest cut. Just as the blade is stopping - not under power. Then I re measure to make sure it is exact.

If you think it may have moved, you can lower the stopped blade to the piece to see if the blade and your mark are still aligned as you need.

If there’s a risk of cutting on the wrong side of the line, mark a small scribble on the bit you’re removing.
I wouldn't condone stopping a slowing blade with material.

If your saw has a laser it might be slightly out of line with the blade. Maybe ignore it. Just drop your (un-powered) blade onto the material and shift whatever you are cutting until the tooth edge is touching the waste side of your pencil line. Lift blade, start and drop into cut. Use a sharp pencil for accurate marking.
personally I measure, mark, mark the offcut with an x, then on the saw I'd be looking to just remove the pencil line with the blade and no more. I don't think that there is a right and a wrong it is just important to measure and cut with the same thought process.

Once I was happy with the length I'd then possibly set up stop blocks for repeating the cuts if needed. You also need to think about sawdust building up on the saw, brush or blow off the surfaces regularly , and take the bottom corners off the stop block so the sawdust can push out of the way and not throw off your measurements and angles. possibly not explaining that well, this video explains...
Lasers can be tricky to set up and if you change a blade the require resetting, some of the more expensive machines have 2 separate lasers.
I have fitted an LED shadow light to my saw, (Bosch)
The light gives a solid line the exact same width as the blade kerf the whole of the line will be removed by the cut
Using a marking knife and my shadow light I can achieve very accurate results time after time, also no adjustment id required when a blade change takes place
Dewalt do a range of saws with a shadow light,
I purchased a small LED light from Amazon and a few mins work with a hot glue gun and I was good to go £7ish
Hope this helps
No mention of the make or model of the saw, if it is not a tight saw then any play will give variable results, my first ever mitre saw was great for fences and sheds but no good for anything needing to be really precise as it just had movement that could not be overcome.
Quite agree @COWS - maybe what I said was misleading. I meant touch the workpiece JUST as the blade is stopping.

If you are careful only the outer parts of the teeth mark the piece, but you know exactly where the cut will be.
with a sharp blade and a decent saw u should be able to cut within 10 thou...
for a fine trim, were talking thou's.....
I touch the wood on a stationary blade then push the wood slighty to *bend the blade*,
then lift the blade keeping the wood still and start the machine up......
depending on feel etc u can cut minute amounts off......been doing this for as long as I can remember....
esp useful when coving ceilings etc when custom angles are needed.....
But sounds like ur not so experienced...? or ur machine is not very healthy.....
My 90 tooth blades get sharpened very reg.....esp if starting a big or accurate job.....
plus have seperate blades for real wood, general man made products and another just for MDF...
even have one for flooring laminate...
u cant trust a new blade even from a decent manuf to be really sharp.......
When I buy a new blade it goes straight to the grinders before use.....

when using stop blocks the stop needs to be moved out of the way or u can experience a jammed wood......
Just shows how ambiguous words can be! Far from impatience, you need to wait until the blade is hardly moving. See post at 07.35 and clarification at 09.55.

However I bow to your greater experience - safety is the priority. I did not intend to suggest bad practice, but a solution that works for me.
On the line if doing 1st fix carpentry / outdoor woodwork.

To the l/r if doing 2nd fix or cabinetry.

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