Compound sliding /mitre saw accurate cuts

[NosamLuap]

Lots of good advice already. The only thing I can add is to ask how you're measuring the line? You might get better results by NOT using a tape measure - e.g. if you want several pieces 'the same length' of 300mm, is it more important that each one is 300mm, or is it more important that each one is the same, and maybe 4 at 302mm is OK... in which case, don't measure, use a stop. If you need to accurately 'match' something, can you use that something as the measure? e.g. can you place the first piece on the saw, touching the blade, then set a stop, and then use that stop to cut your next piece?

You definitely need to account for blade kerf, and knowing which is the 'waste side' of your wood, and knowing which side of your line to cut, is critical. I find it helpful to mark which side is 'waste' when I mark the line. If you're chasing real accuracy, then a mechanical pencil can be more accurate than a regular one if not regularly sharpened, and a marking knife can be more accurate still.

 

[imageel]

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......
LET THE BLADE DO THE WORK....
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......

I used this technique when cutting parquet flooring and it is super easy using this technique to 'creep' up to a knife-line or whatever.
One challenge I had when cutting the parquet was that even with a small square it was very difficult not to get parallax errors when marking up a gap in the blocks, and using this technique it was super easy to incrementally take slivers off across the grain and achieve a tight fit. I can't remember now the precise difference between the blade thickness versus the carbide tip's offset but I did measure it so as to easily get a feel for how much would be removed if I butted the work-piece against the blade body and then perform a plunge cut - in practice even though I have a dial caliper it's difficult to measure since on the factory blade fitted to my Evolution saw has offset tips and the likely error in performing the measurement/calcs using shims is probably greater than the offset or likely (albeit small) run-out on the blade.
It's simple to get pretty close by marking up a scrap piece and performing some test cuts to get the ballpark feel of it and as Clogs noted once you find to step cut produced you can cut marginally over by deflecting the blade!

 

[Spectric]

if you want several pieces 'the same length' of 300mm, is it more important that each one is 300mm, or is it more important that each one is the same,

In many cases both, but by using a stop once you get the first one correct then you can cut as many more of the same length as you like. This is how I always do it for multiple pieces rather than trying to measure each one and end up with variation.